Stable version 0.7.0

This release is dedicated to RetroArch: the second best way to make your
PC feel like a 16bit system (right after building ShellCheck with GHC)

.compile_binaries

@@ -0,0 +1,82 @@
+#!/bin/bash
+
+_cleanup(){
+  rm -rf dist shellcheck || true
+}
+
+build_linux() {
+  # Linux Docker image
+  name="$DOCKER_BASE"
+  DOCKER_BUILDS="$DOCKER_BUILDS $name"
+  docker build -t "$name:current" .
+  docker run "$name:current" --version
+  printf '%s\n' "#!/bin/sh" "echo 'hello world'" > myscript
+  docker run -v "$PWD:/mnt" "$name:current" myscript
+
+  # Copy static executable from docker image
+  id=$(docker create "$name:current")
+  docker cp "$id:/bin/shellcheck" "shellcheck"
+  docker rm "$id"
+  ls -l shellcheck
+  ./shellcheck myscript
+  for tag in $TAGS
+  do 
+    cp "shellcheck" "deploy/shellcheck-$tag.linux-x86_64"; 
+  done
+
+  # Linux Alpine based Docker image
+  name="$DOCKER_BASE-alpine"
+  DOCKER_BUILDS="$DOCKER_BUILDS $name"
+  sed -e '/DELETE-MARKER/,$d' Dockerfile > Dockerfile.alpine
+  docker build -f Dockerfile.alpine -t "$name:current" .
+  docker run "$name:current" sh -c 'shellcheck --version'
+  _cleanup
+}
+
+build_aarch64() {
+  # Linux aarch64 static executable
+  docker run -v "$PWD:/mnt" koalaman/aarch64-builder 'buildsc'
+  for tag in $TAGS
+  do
+    cp "shellcheck" "deploy/shellcheck-$tag.linux-aarch64"
+  done
+}
+
+
+build_armv6hf() {
+  # Linux armv6hf static executable
+  docker run -v "$PWD:/mnt" koalaman/armv6hf-builder -c 'compile-shellcheck'
+  for tag in $TAGS
+  do 
+    cp "shellcheck" "deploy/shellcheck-$tag.linux-armv6hf"; 
+  done
+  _cleanup
+}
+
+build_windows() {
+  # Windows .exe
+  docker run --user="$UID" -v "$PWD:/appdata" koalaman/winghc cuib
+  for tag in $TAGS
+  do 
+    cp "dist/build/ShellCheck/shellcheck.exe" "deploy/shellcheck-$tag.exe"; 
+  done
+  _cleanup
+}
+
+build_osx() {
+  # Darwin x86_64 static executable
+  brew install cabal-install pandoc gnu-tar
+  sudo ln -s /usr/local/bin/gsha512sum /usr/local/bin/sha512sum
+  sudo ln -s /usr/local/bin/gtar /usr/local/bin/tar
+  export PATH="/usr/local/bin:$PATH"
+
+  cabal update
+  cabal install --dependencies-only
+  cabal build shellcheck
+  for tag in $TAGS
+  do 
+    cp "dist/build/shellcheck/shellcheck" "deploy/shellcheck-$tag.darwin-x86_64";
+  done
+  _cleanup
+}
+

.dockerignore

@@ -0,0 +1,6 @@
+*
+!LICENSE
+!Setup.hs
+!ShellCheck.cabal
+!shellcheck.hs
+!src

.ghci

@@ -0,0 +1 @@
+:set -idist/build/autogen -isrc

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+#### For bugs
+- Rule Id (if any, e.g. SC1000): 
+- My shellcheck version (`shellcheck --version` or "online"): 
+- [ ] The rule's wiki page does not already cover this (e.g. https://shellcheck.net/wiki/SC2086)
+- [ ] I tried on shellcheck.net and verified that this is still a problem on the latest commit
+
+#### For new checks and feature suggestions
+- [ ] shellcheck.net (i.e. the latest commit) currently gives no useful warnings about this
+- [ ] I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related
+
+
+#### Here's a snippet or screenshot that shows the problem:
+
+```sh
+
+#!/your/interpreter
+your script here
+
+```
+
+#### Here's what shellcheck currently says:
+
+
+
+#### Here's what I wanted or expected to see:
+
+

.gitignore

@@ -1,4 +1,4 @@
-# Created by http://www.gitignore.io
+# Created by https://www.gitignore.io
 
 ### Haskell ###
 dist
@@ -12,4 +12,11 @@ cabal-dev
 .cabal-sandbox/
 cabal.sandbox.config
 cabal.config
+.stack-work
 
+### Snap ###
+/snap/.snapcraft/
+/stage/
+/parts/
+/prime/
+*.snap

.prepare_deploy

@@ -0,0 +1,65 @@
+#!/bin/bash
+# This script packages up Travis compiled binaries
+set -ex
+shopt -s nullglob
+cd deploy
+
+cp ../LICENSE LICENSE.txt
+sed -e $'s/$/\r/' > README.txt << END
+This is a precompiled ShellCheck binary.
+      https://www.shellcheck.net/
+
+ShellCheck is a static analysis tool for shell scripts.
+It's licensed under the GNU General Public License v3.0.
+Information and source code is available on the website.
+
+This binary was compiled on $(date -u).
+
+
+
+      ====== Latest commits ======
+
+$(git log -n 3)
+END
+
+for file in ./*.exe
+do
+  zip "${file%.*}.zip" README.txt LICENSE.txt "$file"
+done
+
+for file in *.linux-x86_64
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.linux.x86_64.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in *.linux-aarch64
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.linux.aarch64.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in *.linux-armv6hf
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.linux.armv6hf.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in *.darwin-x86_64
+do
+  base="${file%.*}"
+  cp "$file" "shellcheck"
+  tar -cJf "$base.darwin.x86_64.tar.xz" --transform="s:^:$base/:" README.txt LICENSE.txt shellcheck
+  rm "shellcheck"
+done
+
+for file in ./*
+do
+  sha512sum "$file" > "$file.sha512sum"
+done

.snapsquid.conf

@@ -0,0 +1,14 @@
+# In 2015, cabal-install had a http bug triggered when proxies didn't keep
+# the connection open. This version made it into Ubuntu Xenial as used by
+# Snapcraft. In June 2018, Snapcraft's proxy started triggering this bug.
+#
+#     https://bugs.launchpad.net/launchpad-buildd/+bug/1797809
+#
+# Workaround: add more proxy
+
+visible_hostname localhost
+http_port 8888
+cache_peer 10.10.10.1 parent 8222 0 no-query default
+cache_peer_domain localhost !.internal
+http_access allow all
+

.travis.yml

@@ -0,0 +1,66 @@
+
+sudo: required
+
+language: sh
+
+services:
+  - docker
+
+matrix:
+  include:
+    - os: linux
+      env: BUILD=linux
+    - os: linux
+      env: BUILD=windows
+    - os: linux
+      env: BUILD=armv6hf
+    - os: linux
+      env: BUILD=aarch64
+    - os: osx
+      env: BUILD=osx
+
+before_install: |
+  DOCKER_BASE="$DOCKER_USERNAME/shellcheck"
+  DOCKER_BUILDS=""
+  TAGS=""
+  test "$TRAVIS_BRANCH" = master && TAGS="$TAGS latest" || true
+  test -n "$TRAVIS_TAG"          && TAGS="$TAGS stable $TRAVIS_TAG" || true
+  echo "Tags are $TAGS"
+
+script:
+  - mkdir -p deploy
+  - source ./.compile_binaries
+  - ./striptests
+  - set -x; build_"$BUILD"; set +x;
+  - ./.prepare_deploy
+
+after_success: |
+  if [ "$BUILD" = "linux" ]; then
+    docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD"
+    for repo in $DOCKER_BUILDS; do
+      for tag in $TAGS; do
+        echo "Deploying $repo:current as $repo:$tag...";
+        docker tag "$repo:current" "$repo:$tag" || exit 1;
+        docker push "$repo:$tag" || exit 1;
+      done;
+    done;
+  fi
+
+after_failure: |
+  id
+  pwd
+  df -h
+  find . -name '*.log' -type f -exec grep "" /dev/null {} +
+  find . -ls
+
+deploy:
+  provider: gcs
+  skip_cleanup: true
+  access_key_id: GOOG7MDN7WEH6IIGBDCA
+  secret_access_key:
+    secure: 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
+  bucket: shellcheck
+  local-dir: deploy
+  on:
+    repo: koalaman/shellcheck
+    all_branches: true

CHANGELOG.md

@@ -0,0 +1,394 @@
+## v0.7.0 - 2019-07-28
+### Added
+- Precompiled binaries for macOS and Linux aarch64
+- Preliminary support for fix suggestions
+- New `-f diff` unified diff format for auto-fixes
+- Files containing Bats tests can now be checked
+- Directory wide directives can now be placed in a `.shellcheckrc`
+- Optional checks: Use `--list-optional` to show a list of tests,
+                   Enable with `-o` flags or `enable=name` directives
+- Source paths: Use `-P dir1:dir2` or a `source-path=dir1` directive
+                to specify search paths for sourced files.
+- json1 format like --format=json but treats tabs as single characters
+- Recognize FLAGS variables created by the shflags library.
+- Site-specific changes can now be made in Custom.hs for ease of patching
+- SC2154: Also warn about unassigned uppercase variables (optional)
+- SC2252: Warn about `[ $a != x ] || [ $a != y ]`, similar to SC2055
+- SC2251: Inform about ineffectual ! in front of commands
+- SC2250: Warn about variable references without braces (optional)
+- SC2249: Warn about `case` with missing default case (optional)
+- SC2248: Warn about unquoted variables without special chars (optional)
+- SC2247: Warn about $"(cmd)" and $"{var}"
+- SC2246: Warn if a shebang's interpreter ends with /
+- SC2245: Warn that Ksh ignores all but the first glob result in `[`
+- SC2243/SC2244: Suggest using explicit -n for `[ $foo ]` (optional)
+- SC1135: Suggest not ending double quotes just to make $ literal
+
+### Changed
+- If a directive or shebang is not specified, a `.bash/.bats/.dash/.ksh`
+  extension will be used to infer the shell type when present.
+- Disabling SC2120 on a function now disables SC2119 on call sites
+
+### Fixed
+- SC2183 no longer warns about missing printf args for `%()T`
+
+## v0.6.0 - 2018-12-02
+### Added
+- Command line option --severity/-S for filtering by minimum severity
+- Command line option --wiki-link-count/-W for showing wiki links
+- SC2152/SC2151: Warn about bad `exit` values like `1234` and `"foo"`
+- SC2236/SC2237: Suggest -n/-z instead of ! -z/-n
+- SC2238: Warn when redirecting to a known command name, e.g. ls > rm
+- SC2239: Warn if the shebang is not an absolute path, e.g. #!bin/sh
+- SC2240: Warn when passing additional arguments to dot (.) in sh/dash
+- SC1133: Better diagnostics when starting a line with |/||/&&
+
+### Changed
+- Most warnings now have useful end positions
+- SC1117 about unknown double-quoted escape sequences has been retired
+
+### Fixed
+- SC2021 no longer triggers for equivalence classes like `[=e=]`
+- SC2221/SC2222 no longer mistriggers on fall-through case branches
+- SC2081 about glob matches in `[ .. ]` now also triggers for `!=`
+- SC2086 no longer warns about spaces in `$#`
+- SC2164 no longer suggests subshells for `cd ..; cmd; cd ..`
+- `read -a` is now correctly considered an array assignment
+- SC2039 no longer warns about LINENO now that it's POSIX
+
+## v0.5.0 - 2018-05-31
+### Added
+- SC2233/SC2234/SC2235: Suggest removing or replacing (..) around tests
+- SC2232: Warn about invalid arguments to sudo
+- SC2231: Suggest quoting expansions in for loop globs
+- SC2229: Warn about 'read $var'
+- SC2227: Warn about redirections in the middle of 'find' commands
+- SC2224/SC2225/SC2226: Warn when using mv/cp/ln without a destination
+- SC2223: Quote warning specific to `: ${var=value}`
+- SC1131: Warn when using `elseif` or `elsif`
+- SC1128: Warn about blanks/comments before shebang
+- SC1127: Warn about C-style comments
+
+### Fixed
+- Annotations intended for a command's here documents now work
+- Escaped characters inside groups in =~ regexes now parse
+- Associative arrays are now respected in arithmetic contexts
+- SC1087 about `$var[@]` now correctly triggers on any index
+- Bad expansions in here documents are no longer ignored
+- FD move operations like {fd}>1- now parse correctly
+
+### Changed
+- Here docs are now terminated as per spec, rather than by presumed intent
+- SC1073: 'else if' is now parsed correctly and not like 'elif'
+- SC2163: 'export $name' can now be silenced with 'export ${name?}'
+- SC2183: Now warns when printf arg count is not a multiple of format count
+
+## v0.4.7 - 2017-12-08
+### Added
+- Statically linked binaries for Linux and Windows (see README.md)!
+- `-a` flag to also include warnings in `source`d files
+- SC2221/SC2222: Warn about overridden case branches
+- SC2220: Warn about unhandled error cases in getopt loops
+- SC2218: Warn when using functions before they're defined
+- SC2216/SC2217: Warn when piping/redirecting to mv/cp and other non-readers
+- SC2215: Warn about commands starting with leading dash
+- SC2214: Warn about superfluous getopt flags
+- SC2213: Warn about unhandled getopt flags
+- SC2212: Suggest `false` over `[ ]`
+- SC2211: Warn when using a glob as a command name
+- SC2210: Warn when redirecting to an integer, e.g. `foo 1>2`
+- SC2206/SC2207: Suggest alternatives when using word splitting in arrays
+- SC1117: Warn about double quoted, undefined backslash sequences
+- SC1113/SC1114/SC1115: Recognized more malformed shebangs
+
+### Fixed
+- `[ -v foo ]` no longer warns if `foo` is undefined
+- SC2037 is now suppressed by quotes, e.g. `PAGER="cat" man foo`
+- Ksh nested array declarations now parse correctly
+- Parameter Expansion without colons are now recognized, e.g. `${foo+bar}`
+- The `lastpipe` option is now respected with regard to subshell warnings
+- `\(` is now respected for grouping in `[`
+- Leading `\` is now ignored for commands, to allow alias suppression
+- Comments are now allowed after directives to e.g. explain 'disable'
+
+
+## v0.4.6 - 2017-03-26
+### Added
+- SC2204/SC2205: Warn about `( -z foo )` and `( foo -eq bar )`
+- SC2200/SC2201: Warn about brace expansion in [/[[
+- SC2198/SC2199: Warn about arrays in [/[[
+- SC2196/SC2197: Warn about deprected egrep/fgrep
+- SC2195: Warn about unmatchable case branches
+- SC2194: Warn about constant 'case' statements
+- SC2193: Warn about `[[ file.png == *.mp3 ]]` and other unmatchables
+- SC2188/SC2189: Warn about redirections without commands
+- SC2186: Warn about deprecated `tempfile`
+- SC1109: Warn when finding `&`/`>`/`<` unquoted
+- SC1108: Warn about missing spaces in `[ var= foo ]`
+
+### Changed
+- All files are now read as UTF-8 with lenient latin1 fallback, ignoring locale
+- Unicode quotes are no longer considered syntactic quotes
+- `ash` scripts will now be checked as `dash` with a warning
+
+### Fixed
+- `-c` no longer suggested when using `grep -o | wc`
+- Comments and whitespace are now allowed before filewide directives
+- Here doc delimters with esoteric quoting like `foo""` are now handled
+- SC2095 about `ssh` in while read loops is now suppressed when using `-n`
+- `%(%Y%M%D)T` now recognized as a single formatter in `printf` checks
+- `grep -F` now suppresses regex related suggestions
+- Command name checks now recognize busybox applet names
+
+
+## v0.4.5 - 2016-10-21
+### Added
+- A Docker build (thanks, kpankonen!)
+- SC2185: Suggest explicitly adding path for `find`
+- SC2184: Warn about unsetting globs (e.g. `unset foo[1]`)
+- SC2183: Warn about `printf` with more formatters than variables
+- SC2182: Warn about ignored arguments with `printf` 
+- SC2181: Suggest using command directly instead of `if [ $? -eq 0 ]`
+- SC1106: Warn when using `test` operators in `(( 1 -eq 2 ))`
+
+### Changed
+- Unrecognized directives now causes a warning rather than parse failure.
+
+### Fixed
+- Indices in associative arrays are now parsed correctly
+- Missing shebang warning squashed when specifying with a directive
+- Ksh multidimensional arrays are now supported
+- Variables in substring ${a:x:y} expansions now count as referenced
+- SC1102 now also handles ambiguous `$((`
+- Using `$(seq ..)` will no longer suggest quoting
+- SC2148 (missing shebang) is now suppressed when using shell directives
+- `[ a '>' b ]` is now recognized as being correctly escaped
+
+
+## v0.4.4 - 2016-05-15
+### Added
+- Haskell Stack support (thanks,  Arguggi!)
+- SC2179/SC2178: Warn when assigning/appending strings to arrays
+- SC1102: Warn about ambiguous `$(((`
+- SC1101: Warn when \\ linebreaks have trailing spaces
+
+### Changed
+- Directives directly after the shebang now apply to the entire file
+
+### Fixed
+- `{$i..10}` is now flagged similar to `{1..$i}`
+
+
+## v0.4.3 - 2016-01-13
+### Fixed
+- Build now works on GHC 7.6.3 as found on Debian Stable/Ubuntu LTS
+
+
+## v0.4.2 - 2016-01-09
+### Added
+- First class support for the `dash` shell
+- The `--color` flag similar to ls/grep's (thanks, haguenau!)
+- SC2174: Warn about unexpected behavior of `mkdir -pm` (thanks, eatnumber1!)
+- SC2172: Warn about non-portable use of signal numbers in `trap`
+- SC2171: Warn about `]]` without leading `[[`
+- SC2168: Warn about `local` outside functions
+
+### Fixed
+- Warnings about unchecked `cd` will no longer trigger with `set -e`
+- `[ a -nt/-ot/-ef b ]` no longer warns about being constant
+- Quoted test operators like `[ foo "<" bar ]` now parse
+- Escaped quotes in backticks now parse correctly
+
+
+## v0.4.1 - 2015-09-05
+### Fixed
+- Added missing files to Cabal, fixing the build
+
+
+## v0.4.0 - 2015-09-05
+### Added
+- Support for following `source`d files
+- Support for setting default flags in `SHELLCHECK_OPTS`
+- An `--external-sources` flag for following arbitrary `source`d files
+- A `source` directive to override the filename to `source`
+- SC2166: Suggest using `[ p ] && [ q ]` over `[ p -a q ]`
+- SC2165: Warn when nested `for` loops use the same variable name
+- SC2164: Warn when using `cd` without checking that it succeeds
+- SC2163: Warn about `export $var`
+- SC2162: Warn when using `read` without `-r`
+- SC2157: Warn about `[ "$var " ]` and similar never-empty string matches
+
+### Fixed
+- `cat -vnE file` and similar will no longer flag as UUOC
+- Nested trinary operators in `(( ))` now parse correctly
+- Ksh `${ ..; }` command expansions now parse
+
+
+## v0.3.8 - 2015-06-20
+### Changed
+- ShellCheck's license has changed from AGPLv3 to GPLv3.
+
+### Added
+- SC2156: Warn about injecting filenames in `find -exec sh -c "{}" \;`
+
+### Fixed
+- Variables and command substitutions in brace expansions are now parsed
+- ANSI colors are now disabled on Windows
+- Empty scripts now parse
+
+
+## v0.3.7 - 2015-04-16
+### Fixed
+- Build now works on GHC 7.10
+- Use `regex-tdfa` over `regex-compat` since the latter crashes on OS X.
+
+## v0.3.6 - 2015-03-28
+### Added
+- SC2155: Warn about masked return values in `export foo=$(exit 1)`
+- SC2154: Warn when a lowercase variable is referenced but not assigned
+- SC2152/SC2151: Warn about bad `return` values like `1234` and `"foo"`
+- SC2150: Warn about `find -exec "shell command" \;`
+
+### Fixed
+- `coproc` is now supported
+- Trinary operator now recognized in `((..))`
+
+### Removed
+- Zsh support has been removed
+
+
+## v0.3.5 - 2014-11-09
+### Added
+- SC2148: Warn when not including a shebang
+- SC2147: Warn about literal ~ in PATH
+- SC1086: Warn about `$` in for loop variables, e.g. `for $i in ..`
+- SC1084: Warn when the shebang uses `!#` instead of `#!`
+
+### Fixed
+- Empty and comment-only backtick expansions now parse
+- Variables used in PS1/PROMPT\_COMMAND/trap now count as referenced
+- ShellCheck now skips unreadable files and directories
+- `-f gcc` on empty files no longer crashes
+- Variables in $".." are now considered quoted
+- Warnings about expansions in single quotes now include backticks
+
+
+## v0.3.4 - 2014-07-08
+### Added
+- SC2146: Warn about precedence when combining `find -o` with actions
+- SC2145: Warn when concatenating arrays and strings
+
+### Fixed
+- Case statements now support `;&` and `;;&`
+- Indices in array declarations now parse correctly
+- `let` expressions now parsed as arithmetic expressions
+- Escaping is now respected in here documents
+
+### Changed
+- Completely drop Makefile in favor of Cabal (thanks rodrigosetti!)
+
+
+## v0.3.3 - 2014-05-29
+### Added
+- SC2144: Warn when using globs in `[/[[`
+- SC2143: Suggesting using `grep -q` over `[ "$(.. | grep)" ]`
+- SC2142: Warn when referencing positional parameters in aliases
+- SC2141: Warn about suspicious IFS assignments like `IFS="\n"`
+- SC2140: Warn about bad embedded quotes like `echo "var="value""`
+- SC2130: Warn when using `-eq` on strings
+- SC2139: Warn about define time expansions in alias definitions
+- SC2129: Suggest command grouping over `a >> log; b >> log; c >> log`
+- SC2128: Warn when expanding arrays without an index
+- SC2126: Suggest `grep -c` over `grep|wc`
+- SC2123: Warn about accidentally overriding `$PATH`, e.g. `PATH=/my/dir`
+- SC1083: Warn about literal `{/}` outside of quotes
+- SC1082: Warn about UTF-8 BOMs
+
+### Fixed
+- SC2051 no longer triggers for `{1,$n}`, only `{1..$n}`
+- Improved detection of single quoted `sed` variables, e.g. `sed '$s///'`
+- Stop warning about single quoted variables in `PS1` and similar
+- Support for Zsh short form loops, `=(..)`
+
+### Removed
+- SC1000 about unescaped lonely `$`, e.g. `grep "^foo$"`
+
+
+## v0.3.2 - 2014-03-22
+### Added
+- SC2121: Warn about trying to `set` variables, e.g. `set var = value`
+- SC2120/SC2119: Warn when a function uses `$1..` if none are ever passed
+- SC2117: Warn when using `su` in interactive mode, e.g. `su foo; whoami` 
+- SC2116: Detect useless use of echo, e.g. `for i in $(echo $var)`
+- SC2115/SC2114: Detect some catastrophic `rm -r "$empty/"` mistakes
+- SC1081: Warn when capitalizing keywords like `While`
+- SC1077: Warn when using acute accents instead of backticks
+
+### Fixed
+- Shells are now properly recognized in shebangs containing flags
+- Stop warning about math on decimals in ksh/zsh
+- Stop warning about decimal comparisons with `=`, e.g. `[ $version = 1.2 ]`
+- Parsing of `|&`
+- `${a[x]}` not counting as a reference of `x`
+- `(( x[0] ))` not counting as a reference of `x`
+
+
+## v0.3.1 - 2014-02-03
+### Added
+- The `-s` flag to specify shell dialect
+- SC2105/SC2104: Warn about `break/continue` outside loops
+- SC1076: Detect invalid `[/[[` arithmetic like `[ 1 + 2 = 3 ]`
+- SC1075: Suggest using `elif` over `else if`
+
+### Fixed
+- Don't warn when comma separating elements in brace expansions
+- Improved detection of single quoted `sed` variables, e.g. `sed '$d'`
+- Parsing of arithmetic for loops using `{..}` instead of `do..done`
+- Don't treat the last pipeline stage as a subshell in ksh/zsh
+
+
+## v0.3.0 - 2014-01-19
+### Added
+- A man page (thanks Dridi!)
+- GCC compatible error reporting (`shellcheck -f gcc`)
+- CheckStyle compatible XML error reporting (`shellcheck -f checkstyle`)
+- Error codes for each warning, e.g. SC1234
+- Allow disabling warnings with `# shellcheck disable=SC1234`
+- Allow disabling warnings with `--exclude`
+- SC2103: Suggest using subshells over `cd foo; bar; cd ..`
+- SC2102: Warn about duplicates in char ranges, e.g. `[10-15]`
+- SC2101: Warn about named classes not inside a char range, e.g. `[:digit:]`
+- SC2100/SC2099: Warn about bad math expressions like `i=i+5`
+- SC2098/SC2097: Warn about `foo=bar echo $foo`
+- SC2095: Warn when using `ssh`/`ffmpeg` in `while read` loops
+- Better warnings for missing here doc tokens
+
+### Fixed
+- Don't warn when single quoting variables with `ssh/perl/eval`
+- `${!var}` is now counted as a variable reference
+
+### Removed
+- Suggestions about using parameter expansion over basename
+- The `jsoncheck` binary. Use `shellcheck -f json` instead. 
+
+
+## v0.2.0 - 2013-10-27
+### Added
+- Suggest `./*` instead of `*` when passing globs to commands
+- Suggest `pgrep` over `ps | grep`
+- Warn about unicode quotes
+- Warn about assigned but unused variables
+- Inform about client side expansion when using `ssh`
+
+### Fixed
+- CLI tool now uses exit codes and stderr canonically
+- Parsing of extglobs containing empty patterns
+- Parsing of bash style `eval foo=(bar)`
+- Parsing of expansions in here documents
+- Parsing of function names containing :+-
+- Don't warn about `find|xargs` when using `-print0`
+
+
+## v0.1.0 - 2013-07-23
+### Added
+- First release

Dockerfile

@@ -0,0 +1,36 @@
+# Build-only image
+FROM ubuntu:18.04 AS build
+USER root
+WORKDIR /opt/shellCheck
+
+# Install OS deps
+RUN apt-get update && apt-get install -y ghc cabal-install
+
+# Install Haskell deps
+# (This is a separate copy/run so that source changes don't require rebuilding)
+COPY ShellCheck.cabal ./
+RUN cabal update && cabal install --dependencies-only --ghc-options="-optlo-Os -split-sections"
+
+# Copy source and build it
+COPY LICENSE Setup.hs shellcheck.hs ./
+COPY src src
+RUN cabal build Paths_ShellCheck && \
+  ghc -optl-static -optl-pthread -isrc -idist/build/autogen --make shellcheck -split-sections -optc-Wl,--gc-sections -optlo-Os && \
+  strip --strip-all shellcheck
+
+RUN mkdir -p /out/bin && \
+  cp shellcheck  /out/bin/
+
+# Resulting Alpine image
+FROM alpine:latest
+LABEL maintainer="Vidar Holen <vidar@vidarholen.net>"
+COPY --from=build /out /
+
+# DELETE-MARKER (Remove everything below to keep the alpine image)
+
+# Resulting ShellCheck image
+FROM scratch
+LABEL maintainer="Vidar Holen <vidar@vidarholen.net>"
+WORKDIR /mnt
+COPY --from=build /out /
+ENTRYPOINT ["/bin/shellcheck"]

LICENSE

@@ -1,21 +1,33 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
-                       Version 3, 19 November 2007
+Employer mandated disclaimer:
 
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+  I am providing code in the repository to you under an open source license.
+  Because this is my personal repository, the license you receive to my code is
+  from me and other individual contributors, and not my employer (Facebook).
+
+  - Vidar "koala_man" Holen
+
+----
+
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
                             Preamble
 
-  The GNU Affero General Public License is a free, copyleft license for
-software and other kinds of works, specifically designed to ensure
-cooperation with the community in the case of network server software.
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
 
   The licenses for most software and other practical works are designed
 to take away your freedom to share and change the works.  By contrast,
-our General Public Licenses are intended to guarantee your freedom to
+the GNU General Public License is intended to guarantee your freedom to
 share and change all versions of a program--to make sure it remains free
-software for all its users.
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
 
   When we speak of free software, we are referring to freedom, not
 price.  Our General Public Licenses are designed to make sure that you
@@ -24,34 +36,44 @@ them if you wish), that you receive source code or can get it if you
 want it, that you can change the software or use pieces of it in new
 free programs, and that you know you can do these things.
 
-  Developers that use our General Public Licenses protect your rights
-with two steps: (1) assert copyright on the software, and (2) offer
-you this License which gives you legal permission to copy, distribute
-and/or modify the software.
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
 
-  A secondary benefit of defending all users' freedom is that
-improvements made in alternate versions of the program, if they
-receive widespread use, become available for other developers to
-incorporate.  Many developers of free software are heartened and
-encouraged by the resulting cooperation.  However, in the case of
-software used on network servers, this result may fail to come about.
-The GNU General Public License permits making a modified version and
-letting the public access it on a server without ever releasing its
-source code to the public.
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
 
-  The GNU Affero General Public License is designed specifically to
-ensure that, in such cases, the modified source code becomes available
-to the community.  It requires the operator of a network server to
-provide the source code of the modified version running there to the
-users of that server.  Therefore, public use of a modified version, on
-a publicly accessible server, gives the public access to the source
-code of the modified version.
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
 
-  An older license, called the Affero General Public License and
-published by Affero, was designed to accomplish similar goals.  This is
-a different license, not a version of the Affero GPL, but Affero has
-released a new version of the Affero GPL which permits relicensing under
-this license.
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
 
   The precise terms and conditions for copying, distribution and
 modification follow.
@@ -60,7 +82,7 @@ modification follow.
 
   0. Definitions.
 
-  "This License" refers to version 3 of the GNU Affero General Public License.
+  "This License" refers to version 3 of the GNU General Public License.
 
   "Copyright" also means copyright-like laws that apply to other kinds of
 works, such as semiconductor masks.
@@ -537,45 +559,35 @@ to collect a royalty for further conveying from those to whom you convey
 the Program, the only way you could satisfy both those terms and this
 License would be to refrain entirely from conveying the Program.
 
-  13. Remote Network Interaction; Use with the GNU General Public License.
-
-  Notwithstanding any other provision of this License, if you modify the
-Program, your modified version must prominently offer all users
-interacting with it remotely through a computer network (if your version
-supports such interaction) an opportunity to receive the Corresponding
-Source of your version by providing access to the Corresponding Source
-from a network server at no charge, through some standard or customary
-means of facilitating copying of software.  This Corresponding Source
-shall include the Corresponding Source for any work covered by version 3
-of the GNU General Public License that is incorporated pursuant to the
-following paragraph.
+  13. Use with the GNU Affero General Public License.
 
   Notwithstanding any other provision of this License, you have
 permission to link or combine any covered work with a work licensed
-under version 3 of the GNU General Public License into a single
+under version 3 of the GNU Affero General Public License into a single
 combined work, and to convey the resulting work.  The terms of this
 License will continue to apply to the part which is the covered work,
-but the work with which it is combined will remain governed by version
-3 of the GNU General Public License.
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
 
   14. Revised Versions of this License.
 
   The Free Software Foundation may publish revised and/or new versions of
-the GNU Affero General Public License from time to time.  Such new versions
-will be similar in spirit to the present version, but may differ in detail to
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
 address new problems or concerns.
 
   Each version is given a distinguishing version number.  If the
-Program specifies that a certain numbered version of the GNU Affero General
+Program specifies that a certain numbered version of the GNU General
 Public License "or any later version" applies to it, you have the
 option of following the terms and conditions either of that numbered
 version or of any later version published by the Free Software
 Foundation.  If the Program does not specify a version number of the
-GNU Affero General Public License, you may choose any version ever published
+GNU General Public License, you may choose any version ever published
 by the Free Software Foundation.
 
   If the Program specifies that a proxy can decide which future
-versions of the GNU Affero General Public License can be used, that proxy's
+versions of the GNU General Public License can be used, that proxy's
 public statement of acceptance of a version permanently authorizes you
 to choose that version for the Program.
 
@@ -633,29 +645,40 @@ the "copyright" line and a pointer to where the full notice is found.
     Copyright (C) <year>  <name of author>
 
     This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
+    it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
+    GNU General Public License for more details.
 
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 Also add information on how to contact you by electronic and paper mail.
 
-  If your software can interact with users remotely through a computer
-network, you should also make sure that it provides a way for users to
-get its source.  For example, if your program is a web application, its
-interface could display a "Source" link that leads users to an archive
-of the code.  There are many ways you could offer source, and different
-solutions will be better for different programs; see section 13 for the
-specific requirements.
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
 
   You should also get your employer (if you work as a programmer) or school,
 if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU AGPL, see
-<http://www.gnu.org/licenses/>.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/philosophy/why-not-lgpl.html>.

README.md

@@ -1,88 +1,515 @@
+[![Build Status](https://travis-ci.org/koalaman/shellcheck.svg?branch=master)](https://travis-ci.org/koalaman/shellcheck)
+
 # ShellCheck - A shell script static analysis tool
 
-http://www.shellcheck.net
+ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh shell scripts:
 
-Copyright 2012-2015, Vidar 'koala_man' Holen
-Licensed under the GNU Affero General Public License, v3
+![Screenshot of a terminal showing problematic shell script lines highlighted](doc/terminal.png)
 
-The goals of ShellCheck are:
+The goals of ShellCheck are
 
-  - To point out and clarify typical beginner's syntax issues,
-    that causes a shell to give cryptic error messages.
+* To point out and clarify typical beginner's syntax issues that cause a shell
+  to give cryptic error messages.
 
-  - To point out and clarify typical intermediate level semantic problems,
-    that causes a shell to behave strangely and counter-intuitively.
+* To point out and clarify typical intermediate level semantic problems that
+  cause a shell to behave strangely and counter-intuitively.
 
-  - To point out subtle caveats, corner cases and pitfalls, that may cause an
-    advanced user's otherwise working script to fail under future circumstances.
+* To point out subtle caveats, corner cases and pitfalls that may cause an
+  advanced user's otherwise working script to fail under future circumstances.
 
-ShellCheck is written in Haskell, and requires 2 GB of memory to compile.
+See [the gallery of bad code](README.md#user-content-gallery-of-bad-code) for examples of what ShellCheck can help you identify!
+
+## Table of Contents
+
+* [How to use](#how-to-use)
+  * [On the web](#on-the-web)
+  * [From your terminal](#from-your-terminal)
+  * [In your editor](#in-your-editor)
+  * [In your build or test suites](#in-your-build-or-test-suites)
+* [Installing](#installing)
+* [Compiling from source](#compiling-from-source)
+  * [Installing Cabal](#installing-cabal)
+  * [Compiling ShellCheck](#compiling-shellcheck)
+  * [Running tests](#running-tests)
+* [Gallery of bad code](#gallery-of-bad-code)
+  * [Quoting](#quoting)
+  * [Conditionals](#conditionals)
+  * [Frequently misused commands](#frequently-misused-commands)
+  * [Common beginner's mistakes](#common-beginners-mistakes)
+  * [Style](#style)
+  * [Data and typing errors](#data-and-typing-errors)
+  * [Robustness](#robustness)
+  * [Portability](#portability)
+  * [Miscellaneous](#miscellaneous)
+* [Testimonials](#testimonials)
+* [Ignoring issues](#ignoring-issues)
+* [Reporting bugs](#reporting-bugs)
+* [Contributing](#contributing)
+* [Copyright](#copyright)
+* [Other Resources](#other-resources)
+
+## How to use
+
+There are a number of ways to use ShellCheck!
+
+### On the web
+
+Paste a shell script on <https://www.shellcheck.net> for instant feedback.
+
+[ShellCheck.net](https://www.shellcheck.net) is always synchronized to the latest git commit, and is the easiest way to give ShellCheck a go. Tell your friends!
+
+### From your terminal
+
+Run `shellcheck yourscript` in your terminal for instant output, as seen above.
+
+### In your editor
+
+You can see ShellCheck suggestions directly in a variety of editors.
+
+* Vim, through [ALE](https://github.com/w0rp/ale), [Neomake](https://github.com/neomake/neomake), or [Syntastic](https://github.com/scrooloose/syntastic):
+
+![Screenshot of Vim showing inlined shellcheck feedback](doc/vim-syntastic.png).
+
+* Emacs, through [Flycheck](https://github.com/flycheck/flycheck) or [Flymake](https://github.com/federicotdn/flymake-shellcheck):
+
+![Screenshot of emacs showing inlined shellcheck feedback](doc/emacs-flycheck.png).
+
+* Sublime, through [SublimeLinter](https://github.com/SublimeLinter/SublimeLinter-shellcheck).
+
+* Atom, through [Linter](https://github.com/AtomLinter/linter-shellcheck).
+
+* VSCode, through [vscode-shellcheck](https://github.com/timonwong/vscode-shellcheck).
+
+* Most other editors, through [GCC error compatibility](shellcheck.1.md#user-content-formats).
+
+### In your build or test suites
+
+While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites.
+It makes canonical use of exit codes, so you can just add a `shellcheck` command as part of the process.
+
+For example, in a Makefile:
+
+```Makefile
+check-scripts:
+    # Fail if any of these files have warnings
+    shellcheck myscripts/*.sh
+```
+
+or in a Travis CI `.travis.yml` file:
+
+```yaml
+script:
+  # Fail if any of these files have warnings
+  - shellcheck myscripts/*.sh
+```
+
+Services and platforms that have ShellCheck pre-installed and ready to use:
+
+* [Travis CI](https://travis-ci.org/)
+* [Codacy](https://www.codacy.com/)
+* [Code Climate](https://codeclimate.com/)
+* [Code Factor](https://www.codefactor.io/)
+
+Services and platforms with third party plugins:
+
+* [SonarQube](https://www.sonarqube.org/) through [sonar-shellcheck-plugin](https://github.com/emerald-squad/sonar-shellcheck-plugin)
+
+Most other services, including [GitLab](https://about.gitlab.com/), let you install
+ShellCheck yourself, either through the system's package manager (see [Installing](#installing)),
+or by downloading and unpacking a [binary release](#installing-the-shellcheck-binary).
+
+It's a good idea to manually install a specific ShellCheck version regardless. This avoids
+any surprise build breaks when a new version with new warnings is published.
+
+For customized filtering or reporting, ShellCheck can output simple JSON, CheckStyle compatible XML,
+GCC compatible warnings as well as human readable text (with or without ANSI colors). See the
+[Integration](https://github.com/koalaman/shellcheck/wiki/Integration) wiki page for more documentation.
 
 ## Installing
 
-On systems with Cabal:
+The easiest way to install ShellCheck locally is through your package manager.
+
+On systems with Cabal (installs to `~/.cabal/bin`):
 
     cabal update
-    cabal install shellcheck
+    cabal install ShellCheck
+
+On systems with Stack (installs to `~/.local/bin`):
+
+    stack update
+    stack install ShellCheck
 
 On Debian based distros:
 
     apt-get install shellcheck
 
+On Arch Linux based distros:
+
+    pacman -S shellcheck
+
+or get the dependency free [shellcheck-static](https://aur.archlinux.org/packages/shellcheck-static/) from the AUR.
+
+On Gentoo based distros:
+
+    emerge --ask shellcheck
+
+On EPEL based distros:
+
+    yum -y install epel-release
+    yum install ShellCheck
+
+On Fedora based distros:
+
+    dnf install ShellCheck
+
+On FreeBSD:
+
+    pkg install hs-ShellCheck
+
 On OS X with homebrew:
 
     brew install shellcheck
 
-ShellCheck is also available as an online service:
+On OpenBSD:
 
-    http://www.shellcheck.net
+    pkg_add shellcheck
 
-## Building with Cabal
+On openSUSE
 
-This sections describes how to build ShellCheck from a source directory.
+    zypper in ShellCheck
 
-First, make sure cabal is installed. On Debian based distros:
+Or use OneClickInstall - <https://software.opensuse.org/package/ShellCheck>
 
-    apt-get install cabal-install
+On Solus:
 
-On Fedora:
+    eopkg install shellcheck
 
-    yum install cabal-install
+On Windows (via [chocolatey](https://chocolatey.org/packages/shellcheck)):
 
-On Mac OS X with homebrew (http://brew.sh/):
+```cmd
+C:\> choco install shellcheck
+```
 
-    brew install cabal-install
+Or Windows (via [scoop](http://scoop.sh)):
 
-On Mac OS X with MacPorts (http://www.macports.org/):
+```cmd
+C:\> scoop install shellcheck
+```
 
-    port install hs-cabal-install
+From Snap Store:
 
-Let cabal update itself, in case your distro version is outdated:
+    snap install --channel=edge shellcheck
+
+From Docker Hub:
+
+```sh
+docker run --rm -v "$PWD:/mnt" koalaman/shellcheck:stable myscript
+# Or :v0.4.7 for that version, or :latest for daily builds
+```
+
+or use `koalaman/shellcheck-alpine` if you want a larger Alpine Linux based image to extend. It works exactly like a regular Alpine image, but has shellcheck preinstalled.
+
+Alternatively, you can download pre-compiled binaries for the latest release here:
+
+* [Linux, x86_64](https://storage.googleapis.com/shellcheck/shellcheck-stable.linux.x86_64.tar.xz) (statically linked)
+* [Linux, armv6hf](https://storage.googleapis.com/shellcheck/shellcheck-stable.linux.armv6hf.tar.xz), i.e. Raspberry Pi (statically linked)
+* [Linux, aarch64](https://storage.googleapis.com/shellcheck/shellcheck-stable.linux.armv6hf.tar.xz) aka ARM64 (statically linked)
+* [MacOS, x86_64](https://shellcheck.storage.googleapis.com/shellcheck-stable.darwin.x86_64.tar.xz)
+* [Windows, x86](https://storage.googleapis.com/shellcheck/shellcheck-stable.zip)
+
+or see the [storage bucket listing](https://shellcheck.storage.googleapis.com/index.html) for checksums, older versions and the latest daily builds.
+
+Distro packages already come with a `man` page. If you are building from source, it can be installed with:
+
+```console
+pandoc -s -f markdown-smart -t man shellcheck.1.md -o shellcheck.1
+sudo mv shellcheck.1 /usr/share/man/man1
+```
+
+### Travis CI
+
+Travis CI has now integrated ShellCheck by default, so you don't need to manually install it.
+
+If you still want to do so in order to upgrade at your leisure or ensure you're
+using the latest release, follow the steps below to install a binary version.
+
+### Installing a pre-compiled binary
+
+The pre-compiled binaries come in `tar.xz` files. To decompress them, make sure
+`xz` is installed.
+On Debian/Ubuntu/Mint, you can `apt install xz-utils`.
+On Redhat/Fedora/CentOS, `yum -y install xz`.
+
+A simple installer may do something like:
+
+```bash
+scversion="stable" # or "v0.4.7", or "latest"
+wget -qO- "https://storage.googleapis.com/shellcheck/shellcheck-${scversion?}.linux.x86_64.tar.xz" | tar -xJv
+cp "shellcheck-${scversion}/shellcheck" /usr/bin/
+shellcheck --version
+```
+
+## Compiling from source
+
+This section describes how to build ShellCheck from a source directory. ShellCheck is written in Haskell and requires 2GB of RAM to compile.
+
+### Installing Cabal
+
+ShellCheck is built and packaged using Cabal. Install the package `cabal-install` from your system's package manager (with e.g. `apt-get`, `brew`, `emerge`, `yum`, or `zypper`).
+
+On MacOS (OS X), you can do a fast install of Cabal using brew, which takes a couple of minutes instead of more than 30 minutes if you try to compile it from source.
+
+    $ brew install cabal-install
+
+On MacPorts, the package is instead called `hs-cabal-install`, while native Windows users should install the latest version of the Haskell platform from <https://www.haskell.org/platform/>
+
+Verify that `cabal` is installed and update its dependency list with
 
     $ cabal update
-    $ cabal install cabal-install
 
-With cabal installed, cd to the ShellCheck source directory and:
+### Compiling ShellCheck
+
+`git clone` this repository, and `cd` to the ShellCheck source directory to build/install:
 
     $ cabal install
 
-This will install ShellCheck to your ~/.cabal/bin directory.
+Or if you intend to run the tests:
 
-Add the directory to your PATH (for bash, add this to your ~/.bashrc file):
+    $ cabal install --enable-tests
 
-    export PATH=$HOME/.cabal/bin:$PATH
+This will compile ShellCheck and install it to your `~/.cabal/bin` directory.
 
-Verify that your PATH is set up correctly:
+Add this directory to your `PATH` (for bash, add this to your `~/.bashrc`):
 
-    $ which shellcheck
-    ~/.cabal/bin/shellcheck
+```sh
+export PATH="$HOME/.cabal/bin:$PATH"
+```
 
-## Running tests
+Log out and in again, and verify that your PATH is set up correctly:
+
+```sh
+$ which shellcheck
+~/.cabal/bin/shellcheck
+```
+
+On native Windows, the `PATH` should already be set up, but the system
+may use a legacy codepage. In `cmd.exe`, `powershell.exe` and Powershell ISE,
+make sure to use a TrueType font, not a Raster font, and set the active
+codepage to UTF-8 (65001) with `chcp`:
+
+```cmd
+chcp 65001
+```
+
+In Powershell ISE, you may need to additionally update the output encoding:
+
+```powershell
+[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+```
+
+### Running tests
 
 To run the unit test suite:
 
-    cabal configure --enable-tests
-    cabal build
-    cabal test
+    $ cabal test
+
+## Gallery of bad code
+
+So what kind of things does ShellCheck look for? Here is an incomplete list of detected issues.
+
+### Quoting
+
+ShellCheck can recognize several types of incorrect quoting:
+
+```sh
+echo $1                           # Unquoted variables
+find . -name *.ogg                # Unquoted find/grep patterns
+rm "~/my file.txt"                # Quoted tilde expansion
+v='--verbose="true"'; cmd $v      # Literal quotes in variables
+for f in "*.ogg"                  # Incorrectly quoted 'for' loops
+touch $@                          # Unquoted $@
+echo 'Don't forget to restart!'   # Singlequote closed by apostrophe
+echo 'Don\'t try this at home'    # Attempting to escape ' in ''
+echo 'Path is $PATH'              # Variables in single quotes
+trap "echo Took ${SECONDS}s" 0    # Prematurely expanded trap
+```
+
+### Conditionals
+
+ShellCheck can recognize many types of incorrect test statements.
+
+```sh
+[[ n != 0 ]]                      # Constant test expressions
+[[ -e *.mpg ]]                    # Existence checks of globs
+[[ $foo==0 ]]                     # Always true due to missing spaces
+[[ -n "$foo " ]]                  # Always true due to literals
+[[ $foo =~ "fo+" ]]               # Quoted regex in =~
+[ foo =~ re ]                     # Unsupported [ ] operators
+[ $1 -eq "shellcheck" ]           # Numerical comparison of strings
+[ $n && $m ]                      # && in [ .. ]
+[ grep -q foo file ]              # Command without $(..)
+[[ "$$file" == *.jpg ]]           # Comparisons that can't succeed
+(( 1 -lt 2 ))                     # Using test operators in ((..))
+```
+
+### Frequently misused commands
+
+ShellCheck can recognize instances where commands are used incorrectly:
+
+```sh
+grep '*foo*' file                 # Globs in regex contexts
+find . -exec foo {} && bar {} \;  # Prematurely terminated find -exec
+sudo echo 'Var=42' > /etc/profile # Redirecting sudo
+time --format=%s sleep 10         # Passing time(1) flags to time builtin
+while read h; do ssh "$h" uptime  # Commands eating while loop input
+alias archive='mv $1 /backup'     # Defining aliases with arguments
+tr -cd '[a-zA-Z0-9]'              # [] around ranges in tr
+exec foo; echo "Done!"            # Misused 'exec'
+find -name \*.bak -o -name \*~ -delete  # Implicit precedence in find
+# find . -exec foo > bar \;       # Redirections in find
+f() { whoami; }; sudo f           # External use of internal functions
+```
+
+### Common beginner's mistakes
+
+ShellCheck recognizes many common beginner's syntax errors:
+
+```sh
+var = 42                          # Spaces around = in assignments
+$foo=42                           # $ in assignments
+for $var in *; do ...             # $ in for loop variables
+var$n="Hello"                     # Wrong indirect assignment
+echo ${var$n}                     # Wrong indirect reference
+var=(1, 2, 3)                     # Comma separated arrays
+array=( [index] = value )         # Incorrect index initialization
+echo $var[14]                     # Missing {} in array references
+echo "Argument 10 is $10"         # Positional parameter misreference
+if $(myfunction); then ..; fi     # Wrapping commands in $()
+else if othercondition; then ..   # Using 'else if'
+f; f() { echo "hello world; }     # Using function before definition
+[ false ]                         # 'false' being true
+if ( -f file )                    # Using (..) instead of test
+```
+
+### Style
+
+ShellCheck can make suggestions to improve style:
+
+```sh
+[[ -z $(find /tmp | grep mpg) ]]  # Use grep -q instead
+a >> log; b >> log; c >> log      # Use a redirection block instead
+echo "The time is `date`"         # Use $() instead
+cd dir; process *; cd ..;         # Use subshells instead
+echo $[1+2]                       # Use standard $((..)) instead of old $[]
+echo $(($RANDOM % 6))             # Don't use $ on variables in $((..))
+echo "$(date)"                    # Useless use of echo
+cat file | grep foo               # Useless use of cat
+```
+
+### Data and typing errors
+
+ShellCheck can recognize issues related to data and typing:
+
+```sh
+args="$@"                         # Assigning arrays to strings
+files=(foo bar); echo "$files"    # Referencing arrays as strings
+declare -A arr=(foo bar)          # Associative arrays without index
+printf "%s\n" "Arguments: $@."    # Concatenating strings and arrays
+[[ $# > 2 ]]                      # Comparing numbers as strings
+var=World; echo "Hello " var      # Unused lowercase variables
+echo "Hello $name"                # Unassigned lowercase variables
+cmd | read bar; echo $bar         # Assignments in subshells
+cat foo | cp bar                  # Piping to commands that don't read
+printf '%s: %s\n' foo             # Mismatches in printf argument count
+```
+
+### Robustness
+
+ShellCheck can make suggestions for improving the robustness of a script:
+
+```sh
+rm -rf "$STEAMROOT/"*            # Catastrophic rm
+touch ./-l; ls *                 # Globs that could become options
+find . -exec sh -c 'a && b {}' \; # Find -exec shell injection
+printf "Hello $name"             # Variables in printf format
+for f in $(ls *.txt); do         # Iterating over ls output
+export MYVAR=$(cmd)              # Masked exit codes
+case $version in 2.*) :;; 2.6.*) # Shadowed case branches
+```
+
+### Portability
+
+ShellCheck will warn when using features not supported by the shebang. For example, if you set the shebang to `#!/bin/sh`, ShellCheck will warn about portability issues similar to `checkbashisms`:
+
+```sh
+echo {1..$n}                     # Works in ksh, but not bash/dash/sh
+echo {1..10}                     # Works in ksh and bash, but not dash/sh
+echo -n 42                       # Works in ksh, bash and dash, undefined in sh
+trap 'exit 42' sigint            # Unportable signal spec
+cmd &> file                      # Unportable redirection operator
+read foo < /dev/tcp/host/22      # Unportable intercepted files
+foo-bar() { ..; }                # Undefined/unsupported function name
+[ $UID = 0 ]                     # Variable undefined in dash/sh
+local var=value                  # local is undefined in sh
+time sleep 1 | sleep 5           # Undefined uses of 'time'
+```
+
+### Miscellaneous
+
+ShellCheck recognizes a menagerie of other issues:
+
+```sh
+PS1='\e[0;32m\$\e[0m '            # PS1 colors not in \[..\]
+PATH="$PATH:~/bin"                # Literal tilde in $PATH
+rm “file”                         # Unicode quotes
+echo "Hello world"                # Carriage return / DOS line endings
+echo hello \                      # Trailing spaces after \
+var=42 echo $var                  # Expansion of inlined environment
+#!/bin/bash -x -e                 # Common shebang errors
+echo $((n/180*100))               # Unnecessary loss of precision
+ls *[:digit:].txt                 # Bad character class globs
+sed 's/foo/bar/' file > file      # Redirecting to input
+while getopts "a" f; do case $f in "b") # Unhandled getopts flags
+```
+
+## Testimonials
+
+> At first you're like "shellcheck is awesome" but then you're like "wtf are we still using bash"
+
+Alexander Tarasikov,
+[via Twitter](https://twitter.com/astarasikov/status/568825996532707330)
+
+## Ignoring issues
+
+Issues can be ignored via environmental variable, command line, individually or globally within a file:
+
+<https://github.com/koalaman/shellcheck/wiki/Ignore>
+
+## Reporting bugs
+
+Please use the GitHub issue tracker for any bugs or feature suggestions:
+
+<https://github.com/koalaman/shellcheck/issues>
+
+## Contributing
+
+Please submit patches to code or documentation as GitHub pull requests! Check
+out the [DevGuide](https://github.com/koalaman/shellcheck/wiki/DevGuide) on the
+ShellCheck Wiki.
+
+Contributions must be licensed under the GNU GPLv3.
+The contributor retains the copyright.
+
+## Copyright
+
+ShellCheck is licensed under the GNU General Public License, v3. A copy of this license is included in the file [LICENSE](LICENSE).
+
+Copyright 2012-2019, [Vidar 'koala_man' Holen](https://github.com/koalaman/) and contributors.
 
 Happy ShellChecking!
+
+## Other Resources
+
+* The wiki has [long form descriptions](https://github.com/koalaman/shellcheck/wiki/Checks) for each warning, e.g. [SC2221](https://github.com/koalaman/shellcheck/wiki/SC2221).
+* ShellCheck does not attempt to enforce any kind of formatting or indenting style, so also check out [shfmt](https://github.com/mvdan/sh)!
+

Setup.hs

@@ -8,21 +8,13 @@ import Distribution.Simple (
   simpleUserHooks )
 import Distribution.Simple.Setup ( SDistFlags )
 
--- | This requires the process package from,
---
---   https://hackage.haskell.org/package/process
---
-import System.Process ( callCommand )
+import System.Process ( system )
 
 
--- | This will use almost the default implementation, except we switch
---   out the default pre-sdist hook with our own, 'myPreSDist'.
---
 main = defaultMainWithHooks myHooks
   where
     myHooks = simpleUserHooks { preSDist = myPreSDist }
 
-
 -- | This hook will be executed before e.g. @cabal sdist@. It runs
 --   pandoc to create the man page from shellcheck.1.md. If the pandoc
 --   command is not found, this will fail with an error message:
@@ -35,9 +27,10 @@ main = defaultMainWithHooks myHooks
 --
 myPreSDist :: Args -> SDistFlags -> IO HookedBuildInfo
 myPreSDist _ _ = do
-  putStrLn "Building the man page..."
+  putStrLn "Building the man page (shellcheck.1) with pandoc..."
   putStrLn pandoc_cmd
-  callCommand pandoc_cmd
+  result <- system pandoc_cmd
+  putStrLn $ "pandoc exited with " ++ show result
   return emptyHookedBuildInfo
   where
-    pandoc_cmd = "pandoc -s -t man shellcheck.1.md -o shellcheck.1"
+    pandoc_cmd = "pandoc -s -f markdown-smart -t man shellcheck.1.md -o shellcheck.1"

ShellCheck.cabal

@@ -1,13 +1,13 @@
 Name:             ShellCheck
-Version:          0.3.6
+Version:          0.7.0
 Synopsis:         Shell script analysis tool
-License:          AGPL-3
+License:          GPL-3
 License-file:     LICENSE
 Category:         Static Analysis
 Author:           Vidar Holen
 Maintainer:       vidar@vidarholen.net
-Homepage:         http://www.shellcheck.net/
-Build-Type:       Simple
+Homepage:         https://www.shellcheck.net/
+Build-Type:       Custom
 Cabal-Version:    >= 1.8
 Bug-reports:      https://github.com/koalaman/shellcheck/issues
 Description:
@@ -28,59 +28,107 @@ Extra-Source-Files:
     shellcheck.1.md
     -- built with a cabal sdist hook
     shellcheck.1
+    -- convenience script for stripping tests
+    striptests
     -- tests
     test/shellcheck.hs
 
+custom-setup
+  setup-depends:
+    base    >= 4    && <5,
+    process >= 1.0  && <1.7,
+    Cabal   >= 1.10 && <2.5
+
 source-repository head
     type: git
     location: git://github.com/koalaman/shellcheck.git
 
 library
+    hs-source-dirs: src
+    if impl(ghc < 8.0)
+      build-depends:
+        semigroups
     build-depends:
-      base >= 4 && < 5,
-      containers,
-      directory,
-      json,
-      mtl,
+      aeson,
+      array,
+      -- GHC 7.6.3 (base 4.6.0.1) is buggy (#1131, #1119) in optimized mode.
+      -- Just disable that version entirely to fail fast.
+      base > 4.6.0.1 && < 5,
+      bytestring,
+      containers >= 0.5,
+      deepseq >= 1.4.0.0,
+      Diff >= 0.2.0,
+      directory >= 1.2.3.0,
+      mtl >= 2.2.1,
+      filepath,
       parsec,
-      regex-compat,
-      QuickCheck >= 2.7.4
+      regex-tdfa,
+      QuickCheck >= 2.7.4,
+      -- When cabal supports it, move this to setup-depends:
+      process
     exposed-modules:
-      ShellCheck.Analytics
       ShellCheck.AST
+      ShellCheck.ASTLib
+      ShellCheck.Analytics
+      ShellCheck.Analyzer
+      ShellCheck.AnalyzerLib
+      ShellCheck.Checker
+      ShellCheck.Checks.Commands
+      ShellCheck.Checks.Custom
+      ShellCheck.Checks.ShellSupport
       ShellCheck.Data
-      ShellCheck.Options
+      ShellCheck.Fixer
+      ShellCheck.Formatter.Format
+      ShellCheck.Formatter.CheckStyle
+      ShellCheck.Formatter.Diff
+      ShellCheck.Formatter.GCC
+      ShellCheck.Formatter.JSON
+      ShellCheck.Formatter.JSON1
+      ShellCheck.Formatter.TTY
+      ShellCheck.Formatter.Quiet
+      ShellCheck.Interface
       ShellCheck.Parser
-      ShellCheck.Simple
+      ShellCheck.Regex
     other-modules:
       Paths_ShellCheck
 
 executable shellcheck
+    if impl(ghc < 8.0)
+      build-depends:
+        semigroups
     build-depends:
-      ShellCheck,
+      aeson,
+      array,
       base >= 4 && < 5,
+      bytestring,
       containers,
-      directory,
-      json,
-      mtl,
-      parsec,
-      regex-compat,
-      transformers,
-      QuickCheck >= 2.7.4
+      deepseq >= 1.4.0.0,
+      Diff >= 0.2.0,
+      directory >= 1.2.3.0,
+      mtl >= 2.2.1,
+      filepath,
+      parsec >= 3.0,
+      QuickCheck >= 2.7.4,
+      regex-tdfa,
+      ShellCheck
     main-is: shellcheck.hs
 
 test-suite test-shellcheck
     type: exitcode-stdio-1.0
     build-depends:
-      ShellCheck,
+      aeson,
+      array,
       base >= 4 && < 5,
+      bytestring,
       containers,
-      directory,
-      json,
-      mtl,
+      deepseq >= 1.4.0.0,
+      Diff >= 0.2.0,
+      directory >= 1.2.3.0,
+      mtl >= 2.2.1,
+      filepath,
       parsec,
-      regex-compat,
-      transformers,
-      QuickCheck >= 2.7.4
+      QuickCheck >= 2.7.4,
+      regex-tdfa,
+      ShellCheck
     main-is: test/shellcheck.hs
 

ShellCheck/Options.hs

@@ -1,14 +0,0 @@
-module ShellCheck.Options where
-
-data Shell = Ksh | Sh | Bash
-    deriving (Show, Eq)
-
-data AnalysisOptions = AnalysisOptions {
-    optionShellType :: Maybe Shell,
-    optionExcludes :: [Integer]
-}
-
-defaultAnalysisOptions = AnalysisOptions {
-    optionShellType = Nothing,
-    optionExcludes = []
-}

ShellCheck/Simple.hs

@@ -1,80 +0,0 @@
-{-
-    This file is part of ShellCheck.
-    http://www.vidarholen.net/contents/shellcheck
-
-    ShellCheck is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    ShellCheck is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
-
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
--}
-{-# LANGUAGE TemplateHaskell #-}
-module ShellCheck.Simple (shellCheck, ShellCheckComment, scLine, scColumn, scSeverity, scCode, scMessage, runTests) where
-
-import Data.List
-import Data.Maybe
-import ShellCheck.Analytics hiding (runTests)
-import ShellCheck.Options
-import ShellCheck.Parser hiding (runTests)
-import Test.QuickCheck.All (quickCheckAll)
-import Text.Parsec.Pos
-
-shellCheck :: AnalysisOptions -> String -> [ShellCheckComment]
-shellCheck options script =
-    let (ParseResult result notes) = parseShell options "-" script in
-        let allNotes = notes ++ concat (maybeToList $ do
-            (tree, posMap) <- result
-            let list = runAnalytics options tree
-            return $ map (noteToParseNote posMap) $ filterByAnnotation tree list
-            )
-        in
-            map formatNote $ nub $ sortNotes allNotes
-
-data ShellCheckComment = ShellCheckComment { scLine :: Int, scColumn :: Int, scSeverity :: String, scCode :: Int, scMessage :: String }
-
-instance Show ShellCheckComment where
-    show c = concat ["(", show $ scLine c, ",", show $ scColumn c, ") ", scSeverity c, ": ", show (scCode c), " ", scMessage c]
-
-severityToString s =
-    case s of
-        ErrorC -> "error"
-        WarningC -> "warning"
-        InfoC -> "info"
-        StyleC -> "style"
-
-formatNote (ParseNote pos severity code text) =
-    ShellCheckComment (sourceLine pos) (sourceColumn pos) (severityToString severity) (fromIntegral code) text
-
-testCheck = shellCheck defaultAnalysisOptions { optionExcludes = [2148] } -- Ignore #! warnings
-prop_findsParseIssue =
-    let comments = testCheck "echo \"$12\"" in
-        length comments == 1 && scCode (head comments) == 1037
-prop_commentDisablesParseIssue1 =
-    null $ testCheck "#shellcheck disable=SC1037\necho \"$12\""
-prop_commentDisablesParseIssue2 =
-    null $ testCheck "#shellcheck disable=SC1037\n#lol\necho \"$12\""
-
-prop_findsAnalysisIssue =
-    let comments = testCheck "echo $1" in
-        length comments == 1 && scCode (head comments) == 2086
-prop_commentDisablesAnalysisIssue1 =
-    null $ testCheck "#shellcheck disable=SC2086\necho $1"
-prop_commentDisablesAnalysisIssue2 =
-    null $ testCheck "#shellcheck disable=SC2086\n#lol\necho $1"
-
-prop_optionDisablesIssue1 =
-    null $ shellCheck (defaultAnalysisOptions { optionExcludes = [2086, 2148] }) "echo $1"
-
-prop_optionDisablesIssue2 =
-    null $ shellCheck (defaultAnalysisOptions { optionExcludes = [2148, 1037] }) "echo \"$10\""
-
-return []
-runTests = $quickCheckAll
-

nextnumber

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# TODO: Find a less trashy way to get the next available error code
+if ! shopt -s globstar
+then
+  echo "Error: This script depends on Bash 4." >&2
+  exit 1
+fi
+
+for i in 1 2
+do
+  last=$(grep -hv "^prop" ./**/*.hs | grep -Ewo "$i[0-9]{3}" | sort -n | tail -n 1)
+  echo "Next ${i}xxx: $((last+1))"
+done

quickrun

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+# quickrun runs ShellCheck in an interpreted mode.
+# This allows testing changes without recompiling.
+
+runghc -isrc -idist/build/autogen shellcheck.hs "$@"

quicktest

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# quicktest runs the ShellCheck unit tests in an interpreted mode.
+# This allows running tests without compiling, which can be faster.
+# 'cabal test' remains the source of truth.
+
+(
+var=$(echo 'main' | ghci test/shellcheck.hs 2>&1 | tee /dev/stderr)
+if [[ $var == *ExitSuccess* ]]
+then
+  exit 0
+else
+  grep -C 3 -e "Fail" -e "Tracing" <<< "$var"
+  exit 1
+fi
+) 2>&1

shellcheck.1.md

@@ -16,7 +16,7 @@ errors and pitfalls where the shell just gives a cryptic error message or
 strange behavior, but it also reports on a few more advanced issues where
 corner cases can cause delayed failures.
 
-ShellCheck gives shell specific advice. Consider the line:
+ShellCheck gives shell specific advice. Consider this line:
 
     (( area = 3.14*r*r ))
 
@@ -29,9 +29,27 @@ will warn that decimals are not supported.
 + For scripts starting with `#!/bin/ksh` (or using `-s ksh`), ShellCheck will
 not warn at all, as `ksh` supports decimals in arithmetic contexts.
 
-
 # OPTIONS
 
+**-a**,\ **--check-sourced**
+
+:   Emit warnings in sourced files. Normally, `shellcheck` will only warn
+    about issues in the specified files. With this option, any issues in
+    sourced files will also be reported.
+
+**-C**[*WHEN*],\ **--color**[=*WHEN*]
+
+:   For TTY output, enable colors *always*, *never* or *auto*. The default
+    is *auto*. **--color** without an argument is equivalent to
+    **--color=always**.
+
+**-i**\ *CODE1*[,*CODE2*...],\ **--include=***CODE1*[,*CODE2*...]
+
+:   Explicitly include only the specified codes in the report. Subsequent **-i**
+    options are cumulative, but all the codes can be specified at once,
+    comma-separated as a single argument. Include options override any provided
+    exclude options.
+
 **-e**\ *CODE1*[,*CODE2*...],\ **--exclude=***CODE1*[,*CODE2*...]
 
 :   Explicitly exclude the specified codes from the report. Subsequent **-e**
@@ -44,15 +62,60 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.
     standard output. Subsequent **-f** options are ignored, see **FORMATS**
     below for more information.
 
+**--list-optional**
+
+:   Output a list of known optional checks. These can be enabled with **-o**
+    flags or **enable** directives.
+
+**--norc**
+
+:   Don't try to look for .shellcheckrc configuration files.
+
+**-o**\ *NAME1*[,*NAME2*...],\ **--enable=***NAME1*[,*NAME2*...]
+
+:   Enable optional checks. The special name *all* enables all of them.
+    Subsequent **-o** options accumulate. This is equivalent to specifying
+    **enable** directives.
+
+**-P**\ *SOURCEPATH*,\ **--source-path=***SOURCEPATH*
+
+:   Specify paths to search for sourced files, separated by `:` on Unix and
+    `;` on Windows. This is equivalent to specifying `search-path`
+    directives.
+
 **-s**\ *shell*,\ **--shell=***shell*
 
-:   Specify Bourne shell dialect. Valid values are *sh*, *bash* and *ksh*.
-    The default is to use the file's shebang, or *bash* if the target shell
-    can't be determined.
+:   Specify Bourne shell dialect. Valid values are *sh*, *bash*, *dash* and *ksh*.
+    The default is to deduce the shell from the file's `shell` directive,
+    shebang, or `.bash/.bats/.dash/.ksh` extension, in that order. *sh* refers to
+    POSIX `sh` (not the system's), and will warn of portability issues.
 
-**-V**\ *version*,\ **--version**
+**-S**\ *SEVERITY*,\ **--severity=***severity*
+
+:   Specify minimum severity of errors to consider. Valid values in order of
+    severity are *error*, *warning*, *info* and *style*.
+    The default is *style*.
+
+**-V**,\ **--version**
+
+:   Print version information and exit.
+
+**-W** *NUM*,\ **--wiki-link-count=NUM**
+
+:   For TTY output, show *NUM* wiki links to more information about mentioned
+    warnings. Set to 0 to disable them entirely.
+
+**-x**,\ **--external-sources**
+
+:   Follow 'source' statements even when the file is not specified as input.
+    By default, `shellcheck` will only follow files specified on the command
+    line (plus `/dev/null`). This option allows following any file the script
+    may `source`.
+
+**FILES...**
+
+:   One or more script files to check, or "-" for standard input.
 
-:   Print version and exit.
 
 # FORMATS
 
@@ -89,27 +152,59 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.
           ...
         </checkstyle>
 
-**json**
+**diff**
+
+:   Auto-fixes in unified diff format. Can be piped to `git apply` or `patch -p1`
+    to automatically apply fixes.
+
+        --- a/test.sh
+        +++ b/test.sh
+        @@ -2,6 +2,6 @@
+         ## Example of a broken script.
+         for f in $(ls *.m3u)
+         do
+        -  grep -qi hq.*mp3 $f \
+        +  grep -qi hq.*mp3 "$f" \
+             && echo -e 'Playlist $f contains a HQ file in mp3 format'
+         done
+
+
+**json1**
 
 :   Json is a popular serialization format that is more suitable for web
     applications. ShellCheck's json is compact and contains only the bare
-    minimum.
+    minimum.  Tabs are counted as 1 character.
+
+        {
+          comments: [
+            {
+              "file": "filename",
+              "line": lineNumber,
+              "column": columnNumber,
+              "level": "severitylevel",
+              "code": errorCode,
+              "message": "warning message"
+            },
+            ...
+          ]
+        }
+
+**json**
+
+:   This is a legacy version of the **json1** format. It's a raw array of
+    comments, and all offsets have a tab stop of 8.
+
+**quiet**
+
+:   Suppress all normal output. Exit with zero if no issues are found,
+    otherwise exit with one. Stops processing after the first issue.
 
-        [
-          {
-            "file": "filename",
-            "line": lineNumber,
-            "column": columnNumber,
-            "level": "severitylevel",
-            "code": errorCode,
-            "message": "warning message"
-          },
-          ...
-        ]
 
 # DIRECTIVES
-ShellCheck directives can be specified as comments in the shell script
-before a command or block:
+
+ShellCheck directives can be specified as comments in the shell script.
+If they appear before the first command, they are considered file-wide.
+Otherwise, they apply to the immediately following command or block:
 
     # shellcheck key=value key=value
     command-or-structure
@@ -119,7 +214,12 @@ For example, to suppress SC2035 about using `./*.jpg`:
     # shellcheck disable=SC2035
     echo "Files: " *.jpg
 
-Here a shell brace group is used to suppress on multiple lines:
+To tell ShellCheck where to look for an otherwise dynamically determined file:
+
+    # shellcheck source=./lib.sh
+    source "$(find_install_dir)/lib.sh"
+
+Here a shell brace group is used to suppress a warning on multiple lines:
 
     # shellcheck disable=SC2016
     {
@@ -134,15 +234,108 @@ Valid keys are:
     The command can be a simple command like `echo foo`, or a compound command
     like a function definition, subshell block or loop.
 
+**enable**
+:   Enable an optional check by name, as listed with **--list-optional**.
+    Only file-wide `enable` directives are considered.
 
-# AUTHOR
-ShellCheck is written and maintained by Vidar Holen.
+**source**
+:   Overrides the filename included by a `source`/`.` statement. This can be
+    used to tell shellcheck where to look for a file whose name is determined
+    at runtime, or to skip a source by telling it to use `/dev/null`.
+
+**source-path**
+:   Add a directory to the search path for `source`/`.` statements (by default,
+    only ShellCheck's working directory is included). Absolute paths will also
+    be rooted in these paths. The special path `SCRIPTDIR` can be used to
+    specify the currently checked script's directory, as in
+    `source-path=SCRIPTDIR` or `source-path=SCRIPTDIR/../libs`. Multiple
+    paths accumulate, and `-P` takes precedence over them.
+
+**shell**
+:   Overrides the shell detected from the shebang.  This is useful for
+    files meant to be included (and thus lacking a shebang), or possibly
+    as a more targeted alternative to 'disable=2039'.
+
+# RC FILES
+
+Unless `--norc` is used, ShellCheck will look for a file `.shellcheckrc` or
+`shellcheckrc` in the script's directory and each parent directory. If found,
+it will read `key=value` pairs from it and treat them as file-wide directives.
+
+Here is an example `.shellcheckrc`:
+
+    # Look for 'source'd files relative to the checked script,
+    # and also look for absolute paths in /mnt/chroot
+    source-path=SCRIPTDIR
+    source-path=/mnt/chroot
+
+    # Turn on warnings for unquoted variables with safe values
+    enable=quote-safe-variables
+
+    # Turn on warnings for unassigned uppercase variables
+    enable=check-unassigned-uppercase
+
+    # Allow using `which` since it gives full paths and is common enough
+    disable=SC2230
+
+If no `.shellcheckrc` is found in any of the parent directories, ShellCheck
+will look in `~/.shellcheckrc` followed by the XDG config directory
+(usually `~/.config/shellcheckrc`) on Unix, or `%APPDATA%/shellcheckrc` on
+Windows. Only the first file found will be used.
+
+Note for Snap users: the Snap sandbox disallows access to hidden files.
+Use `shellcheckrc` without the dot instead.
+
+Note for Docker users: ShellCheck will only be able to look for files that
+are mounted in the container, so `~/.shellcheckrc` will not be read.
+
+
+# ENVIRONMENT VARIABLES
+
+The environment variable `SHELLCHECK_OPTS` can be set with default flags:
+
+    export SHELLCHECK_OPTS='--shell=bash --exclude=SC2016'
+
+Its value will be split on spaces and prepended to the command line on each
+invocation.
+
+# RETURN VALUES
+
+ShellCheck uses the follow exit codes:
+
++ 0: All files successfully scanned with no issues.
++ 1: All files successfully scanned with some issues.
++ 2: Some files could not be processed (e.g. file not found).
++ 3: ShellCheck was invoked with bad syntax (e.g. unknown flag).
++ 4: ShellCheck was invoked with bad options (e.g. unknown formatter).
+
+# LOCALE
+
+This version of ShellCheck is only available in English. All files are
+leniently decoded as UTF-8, with a fallback of ISO-8859-1 for invalid
+sequences. `LC_CTYPE` is respected for output, and defaults to UTF-8 for
+locales where encoding is unspecified (such as the `C` locale).
+
+Windows users seeing `commitBuffer: invalid argument (invalid character)`
+should set their terminal to use UTF-8 with `chcp 65001`.
+
+# AUTHORS
+
+ShellCheck is developed and maintained by Vidar Holen, with assistance from a
+long list of wonderful contributors.
 
 # REPORTING BUGS
+
 Bugs and issues can be reported on GitHub:
 
 https://github.com/koalaman/shellcheck/issues
 
+# COPYRIGHT
+
+Copyright 2012-2019, Vidar Holen and contributors.
+Licensed under the GNU General Public License version 3 or later,
+see https://gnu.org/licenses/gpl.html
+
 # SEE ALSO
 
 sh(1) bash(1)

shellcheck.hs

@@ -1,263 +1,162 @@
 {-
+    Copyright 2012-2019 Vidar Holen
+
     This file is part of ShellCheck.
-    http://www.vidarholen.net/contents/shellcheck
+    https://www.shellcheck.net
 
     ShellCheck is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
+    it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     (at your option) any later version.
 
     ShellCheck is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
+    GNU General Public License for more details.
 
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 -}
-import Control.Exception
-import Control.Monad
-import Control.Monad.Trans
-import Control.Monad.Trans.Error
-import Control.Monad.Trans.List
-import Data.Char
-import Data.Maybe
-import Data.Monoid
-import GHC.Exts
-import GHC.IO.Device
-import Prelude hiding (catch)
-import ShellCheck.Data
-import ShellCheck.Options
-import ShellCheck.Simple
-import ShellCheck.Analytics
-import System.Console.GetOpt
-import System.Directory
-import System.Environment
-import System.Exit
-import System.IO
-import Text.JSON
-import qualified Data.Map as Map
+import qualified ShellCheck.Analyzer
+import           ShellCheck.Checker
+import           ShellCheck.Data
+import           ShellCheck.Interface
+import           ShellCheck.Regex
+
+import qualified ShellCheck.Formatter.CheckStyle
+import           ShellCheck.Formatter.Format
+import qualified ShellCheck.Formatter.Diff
+import qualified ShellCheck.Formatter.GCC
+import qualified ShellCheck.Formatter.JSON
+import qualified ShellCheck.Formatter.JSON1
+import qualified ShellCheck.Formatter.TTY
+import qualified ShellCheck.Formatter.Quiet
+
+import           Control.Exception
+import           Control.Monad
+import           Control.Monad.Except
+import           Data.Bits
+import           Data.Char
+import           Data.Either
+import           Data.Functor
+import           Data.IORef
+import           Data.List
+import qualified Data.Map                        as Map
+import           Data.Maybe
+import           Data.Monoid
+import           Data.Semigroup                  (Semigroup (..))
+import           Prelude                         hiding (catch)
+import           System.Console.GetOpt
+import           System.Directory
+import           System.Environment
+import           System.Exit
+import           System.FilePath
+import           System.IO
 
 data Flag = Flag String String
-data Status = NoProblems | SomeProblems | BadInput | SupportFailure | SyntaxFailure | RuntimeException deriving (Ord, Eq)
+data Status =
+    NoProblems
+    | SomeProblems
+    | SupportFailure
+    | SyntaxFailure
+    | RuntimeException
+  deriving (Ord, Eq, Show)
 
-data JsonComment = JsonComment FilePath ShellCheckComment
-
-instance Error Status where
-    noMsg = RuntimeException
+instance Semigroup Status where
+    (<>) = max
 
 instance Monoid Status where
     mempty = NoProblems
-    mappend = max
+    mappend = (Data.Semigroup.<>)
 
-header = "Usage: shellcheck [OPTIONS...] FILES..."
+data Options = Options {
+    checkSpec        :: CheckSpec,
+    externalSources  :: Bool,
+    sourcePaths      :: [FilePath],
+    formatterOptions :: FormatterOptions,
+    minSeverity      :: Severity
+}
+
+defaultOptions = Options {
+    checkSpec = emptyCheckSpec,
+    externalSources = False,
+    sourcePaths = [],
+    formatterOptions = newFormatterOptions {
+        foColorOption = ColorAuto
+    },
+    minSeverity = StyleC
+}
+
+usageHeader = "Usage: shellcheck [OPTIONS...] FILES..."
 options = [
+    Option "a" ["check-sourced"]
+        (NoArg $ Flag "sourced" "false") "Include warnings from sourced files",
+    Option "C" ["color"]
+        (OptArg (maybe (Flag "color" "always") (Flag "color")) "WHEN")
+        "Use color (auto, always, never)",
+    Option "i" ["include"]
+        (ReqArg (Flag "include") "CODE1,CODE2..") "Consider only given types of warnings",
     Option "e" ["exclude"]
-        (ReqArg (Flag "exclude") "CODE1,CODE2..") "exclude types of warnings",
+        (ReqArg (Flag "exclude") "CODE1,CODE2..") "Exclude types of warnings",
     Option "f" ["format"]
-        (ReqArg (Flag "format") "FORMAT") "output format",
+        (ReqArg (Flag "format") "FORMAT") $
+        "Output format (" ++ formatList ++ ")",
+    Option "" ["list-optional"]
+        (NoArg $ Flag "list-optional" "true") "List checks disabled by default",
+    Option "" ["norc"]
+        (NoArg $ Flag "norc" "true") "Don't look for .shellcheckrc files",
+    Option "o" ["enable"]
+        (ReqArg (Flag "enable") "check1,check2..")
+        "List of optional checks to enable (or 'all')",
+    Option "P" ["source-path"]
+        (ReqArg (Flag "source-path") "SOURCEPATHS")
+        "Specify path when looking for sourced files (\"SCRIPTDIR\" for script's dir)",
     Option "s" ["shell"]
-        (ReqArg (Flag "shell") "SHELLNAME") "Specify dialect (bash,sh,ksh)",
+        (ReqArg (Flag "shell") "SHELLNAME")
+        "Specify dialect (sh, bash, dash, ksh)",
+    Option "S" ["severity"]
+        (ReqArg (Flag "severity") "SEVERITY")
+        "Minimum severity of errors to consider (error, warning, info, style)",
     Option "V" ["version"]
-        (NoArg $ Flag "version" "true") "Print version information"
+        (NoArg $ Flag "version" "true") "Print version information",
+    Option "W" ["wiki-link-count"]
+        (ReqArg (Flag "wiki-link-count") "NUM")
+        "The number of wiki links to show, when applicable",
+    Option "x" ["external-sources"]
+        (NoArg $ Flag "externals" "true") "Allow 'source' outside of FILES",
+    Option "" ["help"]
+        (NoArg $ Flag "help" "true") "Show this usage summary and exit"
     ]
+getUsageInfo = usageInfo usageHeader options
 
-printErr = hPutStrLn stderr
+printErr = lift . hPutStrLn stderr
 
-
-instance JSON (JsonComment) where
-  showJSON (JsonComment filename c) = makeObj [
-      ("file", showJSON $ filename),
-      ("line", showJSON $ scLine c),
-      ("column", showJSON $ scColumn c),
-      ("level", showJSON $ scSeverity c),
-      ("code", showJSON $ scCode c),
-      ("message", showJSON $ scMessage c)
-      ]
-  readJSON = undefined
-
-parseArguments :: [String] -> ErrorT Status IO ([Flag], [FilePath])
+parseArguments :: [String] -> ExceptT Status IO ([Flag], [FilePath])
 parseArguments argv =
     case getOpt Permute options argv of
         (opts, files, []) -> return (opts, files)
         (_, _, errors) -> do
-            liftIO . printErr $ concat errors ++ "\n" ++ usageInfo header options
+            printErr $ concat errors ++ "\n" ++ getUsageInfo
             throwError SyntaxFailure
 
-formats :: Map.Map String (AnalysisOptions -> [FilePath] -> IO Status)
-formats = Map.fromList [
-    ("json", forJson),
-    ("gcc", forGcc),
-    ("checkstyle", forCheckstyle),
-    ("tty", forTty)
+formats :: FormatterOptions -> Map.Map String (IO Formatter)
+formats options = Map.fromList [
+    ("checkstyle", ShellCheck.Formatter.CheckStyle.format),
+    ("diff",  ShellCheck.Formatter.Diff.format options),
+    ("gcc",  ShellCheck.Formatter.GCC.format),
+    ("json", ShellCheck.Formatter.JSON.format),
+    ("json1", ShellCheck.Formatter.JSON1.format),
+    ("tty",  ShellCheck.Formatter.TTY.format options),
+    ("quiet",  ShellCheck.Formatter.Quiet.format options)
     ]
 
-toStatus = liftM (either id (const NoProblems)) . runErrorT
-
-catchExceptions :: IO Status -> IO Status
-catchExceptions action = action -- action `catch` handler
+formatList = intercalate ", " names
   where
-    handler err = do
-        printErr $ show (err :: SomeException)
-        return RuntimeException
+    names = Map.keys $ formats (formatterOptions defaultOptions)
 
-checkComments comments = if null comments then NoProblems else SomeProblems
-
-forTty :: AnalysisOptions -> [FilePath] -> IO Status
-forTty options files = do
-    output <- mapM doFile files
-    return $ mconcat output
-  where
-    clear = ansi 0
-    ansi n = "\x1B[" ++ show n ++ "m"
-
-    colorForLevel "error" = 31 -- red
-    colorForLevel "warning" = 33 -- yellow
-    colorForLevel "info" = 32 -- green
-    colorForLevel "style" = 32 -- green
-    colorForLevel "message" = 1 -- bold
-    colorForLevel "source" = 0 -- none
-    colorForLevel _ = 0 -- none
-
-    colorComment level comment =
-        ansi (colorForLevel level) ++ comment ++ clear
-
-    doFile path = catchExceptions $ do
-        contents <- readContents path
-        doInput path contents
-
-    doInput filename contents = do
-        let fileLines = lines contents
-        let lineCount = length fileLines
-        let comments = getComments options contents
-        let groups = groupWith scLine comments
-        colorFunc <- getColorFunc
-        mapM_ (\x -> do
-            let lineNum = scLine (head x)
-            let line = if lineNum < 1 || lineNum > lineCount
-                            then ""
-                            else fileLines !! (lineNum - 1)
-            putStrLn ""
-            putStrLn $ colorFunc "message"
-                ("In " ++ filename ++" line " ++ show lineNum ++ ":")
-            putStrLn (colorFunc "source" line)
-            mapM_ (\c -> putStrLn (colorFunc (scSeverity c) $ cuteIndent c)) x
-            putStrLn ""
-          ) groups
-        return . checkComments $ comments
-
-    cuteIndent comment =
-        replicate (scColumn comment - 1) ' ' ++
-            "^-- " ++ code (scCode comment) ++ ": " ++ scMessage comment
-
-    code code = "SC" ++ show code
-
-    getColorFunc = do
-        term <- hIsTerminalDevice stdout
-        return $ if term then colorComment else const id
-
-forJson :: AnalysisOptions -> [FilePath] -> IO Status
-forJson options files = catchExceptions $ do
-    comments <- runListT $ do
-        file <- ListT $ return files
-        comment <- ListT $ commentsFor options file
-        return $ JsonComment file comment
-    putStrLn $ encodeStrict comments
-    return $ checkComments comments
-
--- Mimic GCC "file:line:col: (error|warning|note): message" format
-forGcc :: AnalysisOptions -> [FilePath] -> IO Status
-forGcc options files = do
-    files <- mapM process files
-    return $ mconcat files
-  where
-    process file = catchExceptions $ do
-        contents <- readContents file
-        let comments = makeNonVirtual (getComments options contents) contents
-        mapM_ (putStrLn . format file) comments
-        return $ checkComments comments
-
-    format filename c = concat [
-            filename, ":",
-            show $ scLine c, ":",
-            show $ scColumn c, ": ",
-            case scSeverity c of
-                "error" -> "error"
-                "warning" -> "warning"
-                _ -> "note",
-            ": ",
-            concat . lines $ scMessage c,
-            " [SC", show $ scCode c, "]"
-      ]
-
--- Checkstyle compatible output. A bit of a hack to avoid XML dependencies
-forCheckstyle :: AnalysisOptions -> [FilePath] -> IO Status
-forCheckstyle options files = do
-    putStrLn "<?xml version='1.0' encoding='UTF-8'?>"
-    putStrLn "<checkstyle version='4.3'>"
-    statuses <- mapM process files
-    putStrLn "</checkstyle>"
-    return $ mconcat statuses
-  where
-    process file = catchExceptions $ do
-        comments <- commentsFor options file
-        putStrLn (formatFile file comments)
-        return $ checkComments comments
-
-    severity "error" = "error"
-    severity "warning" = "warning"
-    severity _ = "info"
-    attr s v = concat [ s, "='", escape v, "' " ]
-    escape = concatMap escape'
-    escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
-    isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
-
-    formatFile name comments = concat [
-        "<file ", attr "name" name, ">\n",
-            concatMap format comments,
-        "</file>"
-        ]
-
-    format c = concat [
-        "<error ",
-        attr "line" $ show . scLine $ c,
-        attr "column" $ show . scColumn $ c,
-        attr "severity" $ severity . scSeverity $ c,
-        attr "message" $ scMessage c,
-        attr "source" $ "ShellCheck.SC" ++ show (scCode c),
-        "/>\n"
-        ]
-
-commentsFor options file = liftM (getComments options) $ readContents file
-
-getComments = shellCheck
-
-readContents :: FilePath -> IO String
-readContents file =
-    if file == "-"
-    then getContents
-    else readFile file
-
--- Realign comments from a tabstop of 8 to 1
-makeNonVirtual comments contents =
-    map fix comments
-  where
-    ls = lines contents
-    fix c = c {
-        scColumn =
-            if scLine c > 0 && scLine c <= length ls
-            then real (ls !! (scLine c - 1)) 0 0 (scColumn c)
-            else scColumn c
-    }
-    real _ r v target | target <= v = r
-    real [] r v _ = r -- should never happen
-    real ('\t':rest) r v target =
-        real rest (r+1) (v + 8 - (v `mod` 8)) target
-    real (_:rest) r v target = real rest (r+1) (v+1) target
-
-getOption [] _ = Nothing
+getOption [] _                  = Nothing
 getOption (Flag var val:_) name | name == var = return val
-getOption (_:rest) flag = getOption rest flag
+getOption (_:rest) flag         = getOption rest flag
 
 getOptions options name =
     map (\(Flag _ val) -> val) . filter (\(Flag var _) -> var == name) $ options
@@ -271,19 +170,19 @@ split char str =
         else split' rest (a:element)
     split' [] element = [reverse element]
 
-getExclusions options =
-    let elements = concatMap (split ',') $ getOptions options "exclude"
-        clean = dropWhile (not . isDigit)
-    in
-        map (Prelude.read . clean) elements :: [Int]
+toStatus = fmap (either id id) . runExceptT
 
-excludeCodes codes =
-    filter (not . hasCode)
+getEnvArgs = do
+    opts <- getEnv "SHELLCHECK_OPTS" `catch` cantWaitForLookupEnv
+    return . filter (not . null) $ opts `splitOn` mkRegex " +"
   where
-    hasCode c = scCode c `elem` codes
+    cantWaitForLookupEnv :: IOException -> IO String
+    cantWaitForLookupEnv = const $ return ""
 
 main = do
-    args <- getArgs
+    params <- getArgs
+    envOpts  <- getEnvArgs
+    let args = envOpts ++ params
     status <- toStatus $ do
         (flags, files) <- parseArguments args
         process flags files
@@ -291,64 +190,391 @@ main = do
 
 statusToCode status =
     case status of
-        NoProblems -> ExitSuccess
-        SomeProblems -> ExitFailure 1
-        BadInput -> ExitFailure 5
-        SyntaxFailure -> ExitFailure 3
-        SupportFailure -> ExitFailure 4
+        NoProblems       -> ExitSuccess
+        SomeProblems     -> ExitFailure 1
+        SyntaxFailure    -> ExitFailure 3
+        SupportFailure   -> ExitFailure 4
         RuntimeException -> ExitFailure 2
 
-process :: [Flag] -> [FilePath] -> ErrorT Status IO ()
+process :: [Flag] -> [FilePath] -> ExceptT Status IO Status
 process flags files = do
-    options <- foldM (flip parseOption) defaultAnalysisOptions flags
+    options <- foldM (flip parseOption) defaultOptions flags
     verifyFiles files
     let format = fromMaybe "tty" $ getOption flags "format"
-    case Map.lookup format formats of
-        Nothing -> do
-            liftIO $ do
+    let formatters = formats $ formatterOptions options
+    formatter <-
+        case Map.lookup format formatters of
+            Nothing -> do
                 printErr $ "Unknown format " ++ format
                 printErr "Supported formats:"
-                mapM_ (printErr . write) $ Map.keys formats
+                mapM_ (printErr . write) $ Map.keys formatters
+                throwError SupportFailure
+              where write s = "  " ++ s
+            Just f -> ExceptT $ fmap Right f
+    sys <- lift $ ioInterface options files
+    lift $ runFormatter sys formatter options files
+
+runFormatter :: SystemInterface IO -> Formatter -> Options -> [FilePath]
+            -> IO Status
+runFormatter sys format options files = do
+    header format
+    result <- foldM f NoProblems files
+    footer format
+    return result
+  where
+    f :: Status -> FilePath -> IO Status
+    f status file = do
+        newStatus <- process file `catch` handler file
+        return $ status `mappend` newStatus
+    handler :: FilePath -> IOException -> IO Status
+    handler file e = reportFailure file (show e)
+    reportFailure file str = do
+        onFailure format file str
+        return RuntimeException
+
+    process :: FilePath -> IO Status
+    process filename = do
+        input <- siReadFile sys filename
+        either (reportFailure filename) check input
+      where
+        check contents = do
+            let checkspec = (checkSpec options) {
+                csFilename = filename,
+                csScript = contents
+            }
+            result <- checkScript sys checkspec
+            onResult format result sys
+            return $
+                if null (crComments result)
+                then NoProblems
+                else SomeProblems
+
+parseEnum name value list =
+    case filter ((== value) . fst) list of
+        [(name, value)] -> return value
+        [] -> do
+            printErr $ "Unknown value for --" ++ name ++ ". " ++
+                       "Valid options are: " ++ (intercalate ", " $ map fst list)
             throwError SupportFailure
-          where write s = "  " ++ s
-        Just f -> ErrorT $ liftM Left $ f options files
+
+parseColorOption value =
+    parseEnum "color" value [
+        ("auto",   ColorAuto),
+        ("always", ColorAlways),
+        ("never",  ColorNever)
+        ]
+
+parseSeverityOption value =
+    parseEnum "severity" value [
+        ("error",   ErrorC),
+        ("warning", WarningC),
+        ("info",    InfoC),
+        ("style",   StyleC)
+        ]
 
 parseOption flag options =
     case flag of
         Flag "shell" str ->
-                fromMaybe (die $ "Unknown shell: " ++ str) $ do
-                    shell <- shellForExecutable str
-                    return $ return options { optionShellType = Just shell }
+            fromMaybe (die $ "Unknown shell: " ++ str) $ do
+                shell <- shellForExecutable str
+                return $ return options {
+                            checkSpec = (checkSpec options) {
+                                csShellTypeOverride = Just shell
+                            }
+                        }
 
         Flag "exclude" str -> do
-            new <- mapM parseNum $ split ',' str
-            let old = optionExcludes options
-            return options { optionExcludes = new ++ old }
+            new <- mapM parseNum $ filter (not . null) $ split ',' str
+            let old = csExcludedWarnings . checkSpec $ options
+            return options {
+                checkSpec = (checkSpec options) {
+                    csExcludedWarnings = new ++ old
+                }
+            }
+
+        Flag "include" str -> do
+            new <- mapM parseNum $ filter (not . null) $ split ',' str
+            let old = csIncludedWarnings . checkSpec $ options
+            return options {
+                checkSpec = (checkSpec options) {
+                    csIncludedWarnings =
+                      if null new
+                        then old
+                        else Just new `mappend` old
+                }
+            }
 
         Flag "version" _ -> do
             liftIO printVersion
             throwError NoProblems
 
-        _ -> return options
+        Flag "list-optional" _ -> do
+            liftIO printOptional
+            throwError NoProblems
+
+        Flag "help" _ -> do
+            liftIO $ putStrLn getUsageInfo
+            throwError NoProblems
+
+        Flag "externals" _ ->
+            return options {
+                externalSources = True
+            }
+
+        Flag "color" color -> do
+            option <- parseColorOption color
+            return options {
+                formatterOptions = (formatterOptions options) {
+                    foColorOption = option
+                }
+            }
+
+        Flag "source-path" str -> do
+            let paths = splitSearchPath str
+            return options {
+                sourcePaths = (sourcePaths options) ++ paths
+            }
+
+        Flag "sourced" _ ->
+            return options {
+                checkSpec = (checkSpec options) {
+                    csCheckSourced = True
+                }
+            }
+
+        Flag "severity" severity -> do
+            option <- parseSeverityOption severity
+            return options {
+                checkSpec = (checkSpec options) {
+                    csMinSeverity = option
+                }
+            }
+
+        Flag "wiki-link-count" countString -> do
+            count <- parseNum countString
+            return options {
+                formatterOptions = (formatterOptions options) {
+                    foWikiLinkCount = count
+                }
+            }
+
+        Flag "norc" _ ->
+            return options {
+                checkSpec = (checkSpec options) {
+                    csIgnoreRC = True
+                }
+            }
+
+        Flag "enable" value ->
+            let cs = checkSpec options in return options {
+                checkSpec = cs {
+                    csOptionalChecks = (csOptionalChecks cs) ++ split ',' value
+                }
+            }
+
+        -- This flag is handled specially in 'process'
+        Flag "format" _ -> return options
+
+        Flag str _ -> do
+            printErr $ "Internal error for --" ++ str ++ ". Please file a bug :("
+            return options
   where
     die s = do
-        liftIO $ printErr s
+        printErr s
         throwError SupportFailure
     parseNum ('S':'C':str) = parseNum str
     parseNum num = do
         unless (all isDigit num) $ do
-            liftIO . printErr $ "Bad exclusion: " ++ num
+            printErr $ "Invalid number: " ++ num
             throwError SyntaxFailure
         return (Prelude.read num :: Integer)
 
+ioInterface options files = do
+    inputs <- mapM normalize files
+    cache <- newIORef emptyCache
+    configCache <- newIORef ("", Nothing)
+    return SystemInterface {
+        siReadFile = get cache inputs,
+        siFindSource = findSourceFile inputs (sourcePaths options),
+        siGetConfig = getConfig configCache
+    }
+  where
+    emptyCache :: Map.Map FilePath String
+    emptyCache = Map.empty
+
+    get cache inputs file = do
+        map <- readIORef cache
+        case Map.lookup file map of
+            Just x  -> return $ Right x
+            Nothing -> fetch cache inputs file
+
+    fetch cache inputs file = do
+        ok <- allowable inputs file
+        if ok
+          then (do
+            (contents, shouldCache) <- inputFile file
+            when shouldCache $
+                modifyIORef cache $ Map.insert file contents
+            return $ Right contents
+            ) `catch` handler
+          else return $ Left (file ++ " was not specified as input (see shellcheck -x).")
+      where
+        handler :: IOException -> IO (Either ErrorMessage String)
+        handler ex = return . Left $ show ex
+
+    allowable inputs x =
+        if externalSources options
+        then return True
+        else do
+            path <- normalize x
+            return $ path `elem` inputs
+
+    normalize x =
+        canonicalizePath x `catch` fallback x
+      where
+        fallback :: FilePath -> IOException -> IO FilePath
+        fallback path _ = return path
+
+    -- Returns the name and contents of .shellcheckrc for the given file
+    getConfig cache filename = do
+        path <- normalize filename
+        let dir = takeDirectory path
+        (previousPath, result) <- readIORef cache
+        if dir == previousPath
+          then return result
+          else do
+            paths <- getConfigPaths dir
+            result <- findConfig paths
+            writeIORef cache (dir, result)
+            return result
+
+    findConfig paths =
+        case paths of
+            (file:rest) -> do
+                contents <- readConfig file
+                if isJust contents
+                  then return contents
+                  else findConfig rest
+            [] -> return Nothing
+
+    -- Get a list of candidate filenames. This includes .shellcheckrc
+    -- in all parent directories, plus the user's home dir and xdg dir.
+    -- The dot is optional for Windows and Snap users.
+    getConfigPaths dir = do
+        let next = takeDirectory dir
+        rest <- if next /= dir
+                then getConfigPaths next
+                else defaultPaths `catch`
+                        ((const $ return []) :: IOException -> IO [FilePath])
+        return $ (dir </> ".shellcheckrc") : (dir </> "shellcheckrc") : rest
+
+    defaultPaths = do
+        home <- getAppUserDataDirectory "shellcheckrc"
+        xdg <- getXdgDirectory XdgConfig "shellcheckrc"
+        return [home, xdg]
+
+    readConfig file = do
+        exists <- doesFileExist file
+        if exists
+          then do
+            (contents, _) <- inputFile file `catch` handler file
+            return $ Just (file, contents)
+          else
+            return Nothing
+      where
+        handler :: FilePath -> IOException -> IO (String, Bool)
+        handler file err = do
+            putStrLn $ file ++ ": " ++ show err
+            return ("", True)
+
+    andM a b arg = do
+        first <- a arg
+        if not first then return False else b arg
+
+    findSourceFile inputs sourcePathFlag currentScript sourcePathAnnotation original =
+        if isAbsolute original
+        then
+            let (_, relative) = splitDrive original
+            in find relative original
+        else
+            find original original
+      where
+        find filename deflt = do
+            sources <- filterM ((allowable inputs) `andM` doesFileExist) $
+                        (adjustPath filename):(map (</> filename) $ map adjustPath $ sourcePathFlag ++ sourcePathAnnotation)
+            case sources of
+                [] -> return deflt
+                (first:_) -> return first
+        scriptdir = dropFileName currentScript
+        adjustPath str =
+            case (splitDirectories str) of
+                ("SCRIPTDIR":rest) -> joinPath (scriptdir:rest)
+                _ -> str
+
+inputFile file = do
+    (handle, shouldCache) <-
+            if file == "-"
+            then return (stdin, True)
+            else do
+                h <- openBinaryFile file ReadMode
+                reopenable <- hIsSeekable h
+                return (h, not reopenable)
+
+    hSetBinaryMode handle True
+    contents <- decodeString <$> hGetContents handle -- closes handle
+
+    seq (length contents) $
+        return (contents, shouldCache)
+
+-- Decode a char8 string into a utf8 string, with fallback on
+-- ISO-8859-1. This avoids depending on additional libraries.
+decodeString = decode
+  where
+    decode [] = []
+    decode (c:rest) | isAscii c = c : decode rest
+    decode (c:rest) =
+        let num = (fromIntegral $ ord c) :: Int
+            next = case num of
+                _ | num >= 0xF8 -> Nothing
+                  | num >= 0xF0 -> construct (num .&. 0x07) 3 rest
+                  | num >= 0xE0 -> construct (num .&. 0x0F) 2 rest
+                  | num >= 0xC0 -> construct (num .&. 0x1F) 1 rest
+                  | True -> Nothing
+        in
+            case next of
+                Just (n, remainder) -> chr n : decode remainder
+                Nothing             -> c : decode rest
+
+    construct x 0 rest = do
+        guard $ x <= 0x10FFFF
+        return (x, rest)
+    construct x n (c:rest) =
+        let num = (fromIntegral $ ord c) :: Int in
+            if num >= 0x80 && num <= 0xBF
+            then construct ((x `shiftL` 6) .|. (num .&. 0x3f)) (n-1) rest
+            else Nothing
+    construct _ _ _ = Nothing
+
+
 verifyFiles files =
     when (null files) $ do
-        liftIO $ printErr "No files specified.\n"
-        liftIO $ printErr $ usageInfo header options
+        printErr "No files specified.\n"
+        printErr $ usageInfo usageHeader options
         throwError SyntaxFailure
 
 printVersion = do
     putStrLn   "ShellCheck - shell script analysis tool"
     putStrLn $ "version: " ++ shellcheckVersion
-    putStrLn   "license: GNU Affero General Public License, version 3"
-    putStrLn   "website: http://www.shellcheck.net"
+    putStrLn   "license: GNU General Public License, version 3"
+    putStrLn   "website: https://www.shellcheck.net"
+
+printOptional = do
+    mapM f list
+  where
+    list = sortOn cdName ShellCheck.Analyzer.optionalChecks
+    f item = do
+        putStrLn $ "name:    " ++ cdName item
+        putStrLn $ "desc:    " ++ cdDescription item
+        putStrLn $ "example: " ++ cdPositive item
+        putStrLn $ "fix:     " ++ cdNegative item
+        putStrLn ""

snap/snapcraft.yaml

@@ -0,0 +1,54 @@
+name: shellcheck
+summary: A shell script static analysis tool
+description: |
+  ShellCheck is a GPLv3 tool that gives warnings and suggestions for bash/sh
+  shell scripts.
+
+  The goals of ShellCheck are
+
+  - To point out and clarify typical beginner's syntax issues that cause a
+    shell to give cryptic error messages.
+
+  - To point out and clarify typical intermediate level semantic problems that
+    cause a shell to behave strangely and counter-intuitively.
+
+  - To point out subtle caveats, corner cases and pitfalls that may cause an
+    advanced user's otherwise working script to fail under future
+    circumstances.
+
+  By default ShellCheck can only check non-hidden files under /home, to make 
+  ShellCheck be able to check files under /media and /run/media you must
+  connect it to the `removable-media` interface manually:
+
+      # snap connect shellcheck:removable-media
+  
+version: git
+base: core18
+grade: stable
+confinement: strict
+
+apps:
+  shellcheck:
+    command: usr/bin/shellcheck
+    plugs: [home, removable-media]
+
+parts:
+  shellcheck:
+    plugin: dump
+    source: .
+    build-packages:
+      - cabal-install
+      - squid
+    override-build: |
+      # See comments in .snapsquid.conf
+      [ "$http_proxy" ] && {
+        squid3 -f .snapsquid.conf
+        export http_proxy="http://localhost:8888"
+        sleep 3
+      }
+      cabal sandbox init
+      cabal update || cat /var/log/squid/*
+      cabal install -j
+
+      install -d $SNAPCRAFT_PART_INSTALL/usr/bin
+      install .cabal-sandbox/bin/shellcheck $SNAPCRAFT_PART_INSTALL/usr/bin

src/ShellCheck/AST.hs

@@ -1,59 +1,70 @@
 {-
+    Copyright 2012-2019 Vidar Holen
+
     This file is part of ShellCheck.
-    http://www.vidarholen.net/contents/shellcheck
+    https://www.shellcheck.net
 
     ShellCheck is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published by
+    it under the terms of the GNU General Public License as published by
     the Free Software Foundation, either version 3 of the License, or
     (at your option) any later version.
 
     ShellCheck is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
+    GNU General Public License for more details.
 
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 -}
+{-# LANGUAGE DeriveGeneric, DeriveAnyClass #-}
 module ShellCheck.AST where
 
-import Control.Monad
+import GHC.Generics (Generic)
 import Control.Monad.Identity
-import qualified Text.Regex as Re
+import Control.DeepSeq
+import Text.Parsec
+import qualified ShellCheck.Regex as Re
+import Prelude hiding (id)
 
-data Id = Id Int deriving (Show, Eq, Ord)
+newtype Id = Id Int deriving (Show, Eq, Ord, Generic, NFData)
 
 data Quoted = Quoted | Unquoted deriving (Show, Eq)
 data Dashed = Dashed | Undashed deriving (Show, Eq)
 data AssignmentMode = Assign | Append deriving (Show, Eq)
-data FunctionKeyword = FunctionKeyword Bool deriving (Show, Eq)
-data FunctionParentheses = FunctionParentheses Bool deriving (Show, Eq)
+newtype FunctionKeyword = FunctionKeyword Bool deriving (Show, Eq)
+newtype FunctionParentheses = FunctionParentheses Bool deriving (Show, Eq)
 data CaseType = CaseBreak | CaseFallThrough | CaseContinue deriving (Show, Eq)
 
+newtype Root = Root Token
 data Token =
     TA_Binary Id String Token Token
+    | TA_Assignment Id String Token Token
+    | TA_Variable Id String [Token]
     | TA_Expansion Id [Token]
-    | TA_Index Id Token
     | TA_Sequence Id [Token]
     | TA_Trinary Id Token Token Token
     | TA_Unary Id String Token
     | TC_And Id ConditionType String Token Token
     | TC_Binary Id ConditionType String Token Token
     | TC_Group Id ConditionType Token
-    | TC_Noary Id ConditionType Token
+    | TC_Nullary Id ConditionType Token
     | TC_Or Id ConditionType String Token Token
     | TC_Unary Id ConditionType String Token
+    | TC_Empty Id ConditionType
     | T_AND_IF Id
-    | T_AndIf Id (Token) (Token)
+    | T_AndIf Id Token Token
     | T_Arithmetic Id Token
     | T_Array Id [Token]
-    | T_IndexedElement Id Token Token
-    | T_Assignment Id AssignmentMode String (Maybe Token) Token
+    | T_IndexedElement Id [Token] Token
+    -- Store the index as string, and parse as arithmetic or string later
+    | T_UnparsedIndex Id SourcePos String
+    | T_Assignment Id AssignmentMode String [Token] Token
     | T_Backgrounded Id Token
     | T_Backticked Id [Token]
     | T_Bang Id
     | T_Banged Id Token
-    | T_BraceExpansion Id String
+    | T_BraceExpansion Id [Token]
     | T_BraceGroup Id [Token]
     | T_CLOBBER Id
     | T_Case Id
@@ -65,11 +76,12 @@ data Token =
     | T_DSEMI Id
     | T_Do Id
     | T_DollarArithmetic Id Token
-    | T_DollarBraced Id Token
+    | T_DollarBraced Id Bool Token
     | T_DollarBracket Id Token
     | T_DollarDoubleQuoted Id [Token]
     | T_DollarExpansion Id [Token]
     | T_DollarSingleQuoted Id String
+    | T_DollarBraceCommandExpansion Id [Token]
     | T_Done Id
     | T_DoubleQuoted Id [Token]
     | T_EOF Id
@@ -92,6 +104,7 @@ data Token =
     | T_IfExpression Id [([Token],[Token])] [Token]
     | T_In  Id
     | T_IoFile Id Token Token
+    | T_IoDuplicate Id Token String
     | T_LESSAND Id
     | T_LESSGREAT Id
     | T_Lbrace Id
@@ -101,13 +114,14 @@ data Token =
     | T_NEWLINE Id
     | T_NormalWord Id [Token]
     | T_OR_IF Id
-    | T_OrIf Id (Token) (Token)
+    | T_OrIf Id Token Token
+    | T_ParamSubSpecialChar Id String -- e.g. '%' in ${foo%bar}  or '/' in ${foo/bar/baz}
     | T_Pipeline Id [Token] [Token] -- [Pipe separators] [Commands]
     | T_ProcSub Id String [Token]
     | T_Rbrace Id
     | T_Redirecting Id [Token] Token
     | T_Rparen Id
-    | T_Script Id String [Token]
+    | T_Script Id Token [Token] -- Shebang T_Literal, followed by script.
     | T_Select Id
     | T_SelectIn Id String [Token] [Token]
     | T_Semi Id
@@ -123,18 +137,29 @@ data Token =
     | T_Pipe Id String
     | T_CoProc Id (Maybe String) Token
     | T_CoProcBody Id Token
+    | T_Include Id Token
+    | T_SourceCommand Id Token Token
+    | T_BatsTest Id Token Token
     deriving (Show)
 
-data Annotation = DisableComment Integer deriving (Show, Eq)
+data Annotation =
+    DisableComment Integer
+    | EnableComment String
+    | SourceOverride String
+    | ShellOverride String
+    | SourcePath String
+    deriving (Show, Eq)
 data ConditionType = DoubleBracket | SingleBracket deriving (Show, Eq)
 
--- I apologize for nothing!
-lolHax s = Re.subRegex (Re.mkRegex "(Id [0-9]+)") (show s) "(Id 0)"
+-- This is an abomination.
+tokenEquals :: Token -> Token -> Bool
+tokenEquals a b = kludge a == kludge b
+    where kludge s = Re.subRegex (Re.mkRegex "\\(Id [0-9]+\\)") (show s) "(Id 0)"
+
 instance Eq Token where
-    (==) a b = lolHax a == lolHax b
+    (==) = tokenEquals
 
-
-analyze :: Monad m => (Token -> m ()) -> (Token -> m ()) -> (Token -> Token) -> Token -> m Token
+analyze :: Monad m => (Token -> m ()) -> (Token -> m ()) -> (Token -> m Token) -> Token -> m Token
 analyze f g i =
     round
   where
@@ -142,21 +167,16 @@ analyze f g i =
         f t
         newT <- delve t
         g t
-        return . i $ newT
+        i newT
     roundAll = mapM round
 
-    roundMaybe Nothing = return Nothing
-    roundMaybe (Just v) = do
-        s <- round v
-        return (Just s)
-
     dl l v = do
         x <- roundAll l
         return $ v x
     dll l m v = do
         x <- roundAll l
         y <- roundAll m
-        return $ v x m
+        return $ v x y
     d1 t v = do
         x <- round t
         return $ v x
@@ -169,18 +189,24 @@ analyze f g i =
     delve (T_DoubleQuoted id list) = dl list $ T_DoubleQuoted id
     delve (T_DollarDoubleQuoted id list) = dl list $ T_DollarDoubleQuoted id
     delve (T_DollarExpansion id list) = dl list $ T_DollarExpansion id
+    delve (T_DollarBraceCommandExpansion id list) = dl list $ T_DollarBraceCommandExpansion id
+    delve (T_BraceExpansion id list) = dl list $ T_BraceExpansion id
     delve (T_Backticked id list) = dl list $ T_Backticked id
     delve (T_DollarArithmetic id c) = d1 c $ T_DollarArithmetic id
     delve (T_DollarBracket id c) = d1 c $ T_DollarBracket id
     delve (T_IoFile id op file) = d2 op file $ T_IoFile id
+    delve (T_IoDuplicate id op num) = d1 op $ \x -> T_IoDuplicate id x num
     delve (T_HereString id word) = d1 word $ T_HereString id
     delve (T_FdRedirect id v t) = d1 t $ T_FdRedirect id v
-    delve (T_Assignment id mode var index value) = do
-        a <- roundMaybe index
+    delve (T_Assignment id mode var indices value) = do
+        a <- roundAll indices
         b <- round value
         return $ T_Assignment id mode var a b
     delve (T_Array id t) = dl t $ T_Array id
-    delve (T_IndexedElement id t1 t2) = d2 t1 t2 $ T_IndexedElement id
+    delve (T_IndexedElement id indices t) = do
+        a <- roundAll indices
+        b <- round t
+        return $ T_IndexedElement id a b
     delve (T_Redirecting id redirs cmd) = do
         a <- roundAll redirs
         b <- round cmd
@@ -227,7 +253,7 @@ analyze f g i =
     delve (T_Function id a b name body) = d1 body $ T_Function id a b name
     delve (T_Condition id typ token) = d1 token $ T_Condition id typ
     delve (T_Extglob id str l) = dl l $ T_Extglob id str
-    delve (T_DollarBraced id op) = d1 op $ T_DollarBraced id
+    delve (T_DollarBraced id braced op) = d1 op $ T_DollarBraced id braced
     delve (T_HereDoc id d q str l) = dl l $ T_HereDoc id d q str
 
     delve (TC_And id typ str t1 t2) = d2 t1 t2 $ TC_And id typ str
@@ -235,9 +261,10 @@ analyze f g i =
     delve (TC_Group id typ token) = d1 token $ TC_Group id typ
     delve (TC_Binary id typ op lhs rhs) = d2 lhs rhs $ TC_Binary id typ op
     delve (TC_Unary id typ op token) = d1 token $ TC_Unary id typ op
-    delve (TC_Noary id typ token) = d1 token $ TC_Noary id typ
+    delve (TC_Nullary id typ token) = d1 token $ TC_Nullary id typ
 
     delve (TA_Binary id op t1 t2) = d2 t1 t2 $ TA_Binary id op
+    delve (TA_Assignment id op t1 t2) = d2 t1 t2 $ TA_Assignment id op
     delve (TA_Unary id op t1) = d1 t1 $ TA_Unary id op
     delve (TA_Sequence id l) = dl l $ TA_Sequence id
     delve (TA_Trinary id t1 t2 t3) = do
@@ -246,12 +273,16 @@ analyze f g i =
         c <- round t3
         return $ TA_Trinary id a b c
     delve (TA_Expansion id t) = dl t $ TA_Expansion id
-    delve (TA_Index id t) = d1 t $ TA_Index id
+    delve (TA_Variable id str t) = dl t $ TA_Variable id str
     delve (T_Annotation id anns t) = d1 t $ T_Annotation id anns
     delve (T_CoProc id var body) = d1 body $ T_CoProc id var
     delve (T_CoProcBody id t) = d1 t $ T_CoProcBody id
+    delve (T_Include id script) = d1 script $ T_Include id
+    delve (T_SourceCommand id includer t_include) = d2 includer t_include $ T_SourceCommand id
+    delve (T_BatsTest id name t) = d2 name t $ T_BatsTest id
     delve t = return t
 
+getId :: Token -> Id
 getId t = case t of
         T_AND_IF id  -> id
         T_OR_IF id  -> id
@@ -292,10 +323,13 @@ getId t = case t of
         T_NormalWord id _  -> id
         T_DoubleQuoted id _  -> id
         T_DollarExpansion id _  -> id
-        T_DollarBraced id _  -> id
+        T_DollarBraced id _ _ -> id
         T_DollarArithmetic id _  -> id
         T_BraceExpansion id _  -> id
+        T_ParamSubSpecialChar id _ -> id
+        T_DollarBraceCommandExpansion id _  -> id
         T_IoFile id _ _  -> id
+        T_IoDuplicate id _ _  -> id
         T_HereDoc id _ _ _ _ -> id
         T_HereString id _  -> id
         T_FdRedirect id _ _  -> id
@@ -328,13 +362,13 @@ getId t = case t of
         TC_Group id _ _  -> id
         TC_Binary id _ _ _ _  -> id
         TC_Unary id _ _ _  -> id
-        TC_Noary id _ _  -> id
+        TC_Nullary id _ _  -> id
         TA_Binary id _ _ _  -> id
+        TA_Assignment id _ _ _  -> id
         TA_Unary id _ _  -> id
         TA_Sequence id _  -> id
         TA_Trinary id _ _ _  -> id
         TA_Expansion id _  -> id
-        TA_Index id _  -> id
         T_ProcSub id _ _ -> id
         T_Glob id _ -> id
         T_ForArithmetic id _ _ _ _ -> id
@@ -345,17 +379,19 @@ getId t = case t of
         T_Pipe id _ -> id
         T_CoProc id _ _ -> id
         T_CoProcBody id _ -> id
+        T_Include id _ -> id
+        T_SourceCommand id _ _ -> id
+        T_UnparsedIndex id _ _ -> id
+        TC_Empty id _ -> id
+        TA_Variable id _ _ -> id
+        T_BatsTest id _ _ -> id
 
 blank :: Monad m => Token -> m ()
 blank = const $ return ()
-doAnalysis f = analyze f blank id
-doStackAnalysis startToken endToken = analyze startToken endToken id
-doTransform i = runIdentity . analyze blank blank i
+doAnalysis :: Monad m => (Token -> m ()) -> Token -> m Token
+doAnalysis f = analyze f blank return
+doStackAnalysis :: Monad m => (Token -> m ()) -> (Token -> m ()) -> Token -> m Token
+doStackAnalysis startToken endToken = analyze startToken endToken return
+doTransform :: (Token -> Token) -> Token -> Token
+doTransform i = runIdentity . analyze blank blank (return . i)
 
-isLoop t = case t of
-        T_WhileExpression {} -> True
-        T_UntilExpression {} -> True
-        T_ForIn {} -> True
-        T_ForArithmetic {} -> True
-        T_SelectIn {}  -> True
-        _ -> False

src/ShellCheck/ASTLib.hs

@@ -0,0 +1,513 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.ASTLib where
+
+import ShellCheck.AST
+
+import Control.Monad.Writer
+import Control.Monad
+import Data.Char
+import Data.Functor
+import Data.List
+import Data.Maybe
+
+-- Is this a type of loop?
+isLoop t = case t of
+        T_WhileExpression {} -> True
+        T_UntilExpression {} -> True
+        T_ForIn {} -> True
+        T_ForArithmetic {} -> True
+        T_SelectIn {}  -> True
+        _ -> False
+
+-- Will this split into multiple words when used as an argument?
+willSplit x =
+  case x of
+    T_DollarBraced {} -> True
+    T_DollarExpansion {} -> True
+    T_Backticked {} -> True
+    T_BraceExpansion {} -> True
+    T_Glob {} -> True
+    T_Extglob {} -> True
+    T_NormalWord _ l -> any willSplit l
+    _ -> False
+
+isGlob T_Extglob {} = True
+isGlob T_Glob {} = True
+isGlob (T_NormalWord _ l) = any isGlob l
+isGlob _ = False
+
+-- Is this shell word a constant?
+isConstant token =
+    case token of
+        -- This ignores some cases like ~"foo":
+        T_NormalWord _ (T_Literal _ ('~':_) : _)  -> False
+        T_NormalWord _ l   -> all isConstant l
+        T_DoubleQuoted _ l -> all isConstant l
+        T_SingleQuoted _ _ -> True
+        T_Literal _ _ -> True
+        _ -> False
+
+-- Is this an empty literal?
+isEmpty token =
+    case token of
+        T_NormalWord _ l   -> all isEmpty l
+        T_DoubleQuoted _ l -> all isEmpty l
+        T_SingleQuoted _ "" -> True
+        T_Literal _ "" -> True
+        _ -> False
+
+-- Quick&lazy oversimplification of commands, throwing away details
+-- and returning a list like  ["find", ".", "-name", "${VAR}*" ].
+oversimplify token =
+    case token of
+        (T_NormalWord _ l) -> [concat (concatMap oversimplify l)]
+        (T_DoubleQuoted _ l) -> [concat (concatMap oversimplify l)]
+        (T_SingleQuoted _ s) -> [s]
+        (T_DollarBraced _ _ _) -> ["${VAR}"]
+        (T_DollarArithmetic _ _) -> ["${VAR}"]
+        (T_DollarExpansion _ _) -> ["${VAR}"]
+        (T_Backticked _ _) -> ["${VAR}"]
+        (T_Glob _ s) -> [s]
+        (T_Pipeline _ _ [x]) -> oversimplify x
+        (T_Literal _ x) -> [x]
+        (T_ParamSubSpecialChar _ x) -> [x]
+        (T_SimpleCommand _ vars words) -> concatMap oversimplify words
+        (T_Redirecting _ _ foo) -> oversimplify foo
+        (T_DollarSingleQuoted _ s) -> [s]
+        (T_Annotation _ _ s) -> oversimplify s
+        -- Workaround for let "foo = bar" parsing
+        (TA_Sequence _ [TA_Expansion _ v]) -> concatMap oversimplify v
+        _ -> []
+
+
+-- Turn a SimpleCommand foo -avz --bar=baz into args "a", "v", "z", "bar",
+-- each in a tuple of (token, stringFlag). Non-flag arguments are added with
+-- stringFlag == "".
+getFlagsUntil stopCondition (T_SimpleCommand _ _ (_:args)) =
+    let tokenAndText = map (\x -> (x, concat $ oversimplify x)) args
+        (flagArgs, rest) = break (stopCondition . snd) tokenAndText
+    in
+        concatMap flag flagArgs ++ map (\(t, _) -> (t, "")) rest
+  where
+    flag (x, '-':'-':arg) = [ (x, takeWhile (/= '=') arg) ]
+    flag (x, '-':args) = map (\v -> (x, [v])) args
+    flag (x, _) = [ (x, "") ]
+getFlagsUntil _ _ = error "Internal shellcheck error, please report! (getFlags on non-command)"
+
+-- Get all flags in a GNU way, up until --
+getAllFlags :: Token -> [(Token, String)]
+getAllFlags = getFlagsUntil (== "--")
+-- Get all flags in a BSD way, up until first non-flag argument or --
+getLeadingFlags = getFlagsUntil (\x -> x == "--" || (not $ "-" `isPrefixOf` x))
+
+-- Check if a command has a flag.
+hasFlag cmd str = str `elem` (map snd $ getAllFlags cmd)
+
+-- Is this token a word that starts with a dash?
+isFlag token =
+    case getWordParts token of
+        T_Literal _ ('-':_) : _ -> True
+        _ -> False
+
+-- Is this token a flag where the - is unquoted?
+isUnquotedFlag token = fromMaybe False $ do
+    str <- getLeadingUnquotedString token
+    return $ "-" `isPrefixOf` str
+
+-- Given a T_DollarBraced, return a simplified version of the string contents.
+bracedString (T_DollarBraced _ _ l) = concat $ oversimplify l
+bracedString _ = error "Internal shellcheck error, please report! (bracedString on non-variable)"
+
+-- Is this an expansion of multiple items of an array?
+isArrayExpansion t@(T_DollarBraced _ _ _) =
+    let string = bracedString t in
+        "@" `isPrefixOf` string ||
+            not ("#" `isPrefixOf` string) && "[@]" `isInfixOf` string
+isArrayExpansion _ = False
+
+-- Is it possible that this arg becomes multiple args?
+mayBecomeMultipleArgs t = willBecomeMultipleArgs t || f t
+  where
+    f t@(T_DollarBraced _ _ _) =
+        let string = bracedString t in
+            "!" `isPrefixOf` string
+    f (T_DoubleQuoted _ parts) = any f parts
+    f (T_NormalWord _ parts) = any f parts
+    f _ = False
+
+-- Is it certain that this word will becomes multiple words?
+willBecomeMultipleArgs t = willConcatInAssignment t || f t
+  where
+    f T_Extglob {} = True
+    f T_Glob {} = True
+    f T_BraceExpansion {} = True
+    f (T_DoubleQuoted _ parts) = any f parts
+    f (T_NormalWord _ parts) = any f parts
+    f _ = False
+
+-- This does token cause implicit concatenation in assignments?
+willConcatInAssignment token =
+    case token of
+        t@T_DollarBraced {} -> isArrayExpansion t
+        (T_DoubleQuoted _ parts) -> any willConcatInAssignment parts
+        (T_NormalWord _ parts) -> any willConcatInAssignment parts
+        _ -> False
+
+-- Maybe get the literal string corresponding to this token
+getLiteralString :: Token -> Maybe String
+getLiteralString = getLiteralStringExt (const Nothing)
+
+-- Definitely get a literal string, skipping over all non-literals
+onlyLiteralString :: Token -> String
+onlyLiteralString = fromJust . getLiteralStringExt (const $ return "")
+
+-- Maybe get a literal string, but only if it's an unquoted argument.
+getUnquotedLiteral (T_NormalWord _ list) =
+    concat <$> mapM str list
+  where
+    str (T_Literal _ s) = return s
+    str _ = Nothing
+getUnquotedLiteral _ = Nothing
+
+-- Get the last unquoted T_Literal in a word like "${var}foo"THIS
+-- or nothing if the word does not end in an unquoted literal.
+getTrailingUnquotedLiteral :: Token -> Maybe Token
+getTrailingUnquotedLiteral t =
+    case t of
+        (T_NormalWord _ list@(_:_)) ->
+            from (last list)
+        _ -> Nothing
+  where
+    from t =
+        case t of
+            T_Literal {} -> return t
+            _ -> Nothing
+
+-- Get the leading, unquoted, literal string of a token (if any).
+getLeadingUnquotedString :: Token -> Maybe String
+getLeadingUnquotedString t =
+    case t of
+        T_NormalWord _ ((T_Literal _ s) : _) -> return s
+        _ -> Nothing
+
+-- Maybe get the literal string of this token and any globs in it.
+getGlobOrLiteralString = getLiteralStringExt f
+  where
+    f (T_Glob _ str) = return str
+    f _ = Nothing
+
+-- Maybe get the literal value of a token, using a custom function
+-- to map unrecognized Tokens into strings.
+getLiteralStringExt :: (Token -> Maybe String) -> Token -> Maybe String
+getLiteralStringExt more = g
+  where
+    allInList = fmap concat . mapM g
+    g (T_DoubleQuoted _ l) = allInList l
+    g (T_DollarDoubleQuoted _ l) = allInList l
+    g (T_NormalWord _ l) = allInList l
+    g (TA_Expansion _ l) = allInList l
+    g (T_SingleQuoted _ s) = return s
+    g (T_Literal _ s) = return s
+    g (T_ParamSubSpecialChar _ s) = return s
+    g (T_DollarSingleQuoted _ s) = return $ decodeEscapes s
+    g x = more x
+
+    -- Bash style $'..' decoding
+    decodeEscapes ('\\':c:cs) =
+        case c of
+            'a' -> '\a' : rest
+            'b' -> '\b' : rest
+            'e' -> '\x1B' : rest
+            'f' -> '\f' : rest
+            'n' -> '\n' : rest
+            'r' -> '\r' : rest
+            't' -> '\t' : rest
+            'v' -> '\v' : rest
+            '\'' -> '\'' : rest
+            '"' -> '"' : rest
+            '\\' -> '\\' : rest
+            'x' ->
+                case cs of
+                    (x:y:more) ->
+                        if isHexDigit x && isHexDigit y
+                        then chr (16*(digitToInt x) + (digitToInt y)) : rest
+                        else '\\':c:rest
+            _ | isOctDigit c ->
+                let digits = take 3 $ takeWhile isOctDigit (c:cs)
+                    num = parseOct digits
+                in (if num < 256 then chr num else '?') : rest
+            _ -> '\\' : c : rest
+      where
+        rest = decodeEscapes cs
+        parseOct = f 0
+          where
+            f n "" = n
+            f n (c:rest) = f (n * 8 + digitToInt c) rest
+    decodeEscapes (c:cs) = c : decodeEscapes cs
+    decodeEscapes [] = []
+
+-- Is this token a string literal?
+isLiteral t = isJust $ getLiteralString t
+
+
+-- Turn a NormalWord like foo="bar $baz" into a series of constituent elements like [foo=,bar ,$baz]
+getWordParts (T_NormalWord _ l)   = concatMap getWordParts l
+getWordParts (T_DoubleQuoted _ l) = l
+-- TA_Expansion is basically T_NormalWord for arithmetic expressions
+getWordParts (TA_Expansion _ l)   = concatMap getWordParts l
+getWordParts other                = [other]
+
+-- Return a list of NormalWords that would result from brace expansion
+braceExpand (T_NormalWord id list) = take 1000 $ do
+    items <- mapM part list
+    return $ T_NormalWord id items
+  where
+    part (T_BraceExpansion id items) = do
+        item <- items
+        braceExpand item
+    part x = return x
+
+-- Maybe get a SimpleCommand from immediate wrappers like T_Redirections
+getCommand t =
+    case t of
+        T_Redirecting _ _ w -> getCommand w
+        T_SimpleCommand _ _ (w:_) -> return t
+        T_Annotation _ _ t -> getCommand t
+        _ -> Nothing
+
+-- Maybe get the command name string of a token representing a command
+getCommandName :: Token -> Maybe String
+getCommandName = fst . getCommandNameAndToken
+
+-- Get the command name token from a command, i.e.
+-- the token representing 'ls' in 'ls -la 2> foo'.
+-- If it can't be determined, return the original token.
+getCommandTokenOrThis = snd . getCommandNameAndToken
+
+getCommandNameAndToken :: Token -> (Maybe String, Token)
+getCommandNameAndToken t = fromMaybe (Nothing, t) $ do
+    (T_SimpleCommand _ _ (w:rest)) <- getCommand t
+    s <- getLiteralString w
+    if "busybox" `isSuffixOf` s || "builtin" == s
+        then
+            case rest of
+                (applet:_) -> return (getLiteralString applet, applet)
+                _ -> return (Just s, w)
+        else
+            return (Just s, w)
+
+
+-- If a command substitution is a single command, get its name.
+--  $(date +%s) = Just "date"
+getCommandNameFromExpansion :: Token -> Maybe String
+getCommandNameFromExpansion t =
+    case t of
+        T_DollarExpansion _ [c] -> extract c
+        T_Backticked _ [c] -> extract c
+        T_DollarBraceCommandExpansion _ [c] -> extract c
+        _ -> Nothing
+  where
+    extract (T_Pipeline _ _ [cmd]) = getCommandName cmd
+    extract _ = Nothing
+
+-- Get the basename of a token representing a command
+getCommandBasename = fmap basename . getCommandName
+  where
+    basename = reverse . takeWhile (/= '/') . reverse
+
+isAssignment t =
+    case t of
+        T_Redirecting _ _ w -> isAssignment w
+        T_SimpleCommand _ (w:_) [] -> True
+        T_Assignment {} -> True
+        T_Annotation _ _ w -> isAssignment w
+        _ -> False
+
+isOnlyRedirection t =
+    case t of
+        T_Pipeline _ _ [x] -> isOnlyRedirection x
+        T_Annotation _ _ w -> isOnlyRedirection w
+        T_Redirecting _ (_:_) c -> isOnlyRedirection c
+        T_SimpleCommand _ [] [] -> True
+        _ -> False
+
+isFunction t = case t of T_Function {} -> True; _ -> False
+
+-- Bats tests are functions for the purpose of 'local' and such
+isFunctionLike t =
+    case t of
+        T_Function {} -> True
+        T_BatsTest {} -> True
+        _ -> False
+
+
+isBraceExpansion t = case t of T_BraceExpansion {} -> True; _ -> False
+
+-- Get the lists of commands from tokens that contain them, such as
+-- the body of while loops or branches of if statements.
+getCommandSequences :: Token -> [[Token]]
+getCommandSequences t =
+    case t of
+        T_Script _ _ cmds -> [cmds]
+        T_BraceGroup _ cmds -> [cmds]
+        T_Subshell _ cmds -> [cmds]
+        T_WhileExpression _ _ cmds -> [cmds]
+        T_UntilExpression _ _ cmds -> [cmds]
+        T_ForIn _ _ _ cmds -> [cmds]
+        T_ForArithmetic _ _ _ _ cmds -> [cmds]
+        T_IfExpression _ thens elses -> map snd thens ++ [elses]
+        T_Annotation _ _ t -> getCommandSequences t
+        _ -> []
+
+-- Get a list of names of associative arrays
+getAssociativeArrays t =
+    nub . execWriter $ doAnalysis f t
+  where
+    f :: Token -> Writer [String] ()
+    f t@T_SimpleCommand {} = fromMaybe (return ()) $ do
+        name <- getCommandName t
+        let assocNames = ["declare","local","typeset"]
+        guard $ elem name assocNames
+        let flags = getAllFlags t
+        guard $ elem "A" $ map snd flags
+        let args = map fst . filter ((==) "" . snd) $ flags
+        let names = mapMaybe (getLiteralStringExt nameAssignments) args
+        return $ tell names
+    f _ = return ()
+
+    nameAssignments t =
+        case t of
+            T_Assignment _ _ name _ _ -> return name
+            _ -> Nothing
+
+-- A Pseudoglob is a wildcard pattern used for checking if a match can succeed.
+-- For example, [[ $(cmd).jpg == [a-z] ]] will give the patterns *.jpg and ?, which
+-- can be proven never to match.
+data PseudoGlob = PGAny | PGMany | PGChar Char
+    deriving (Eq, Show)
+
+-- Turn a word into a PG pattern, replacing all unknown/runtime values with
+-- PGMany.
+wordToPseudoGlob :: Token -> Maybe [PseudoGlob]
+wordToPseudoGlob word =
+    simplifyPseudoGlob . concat <$> mapM f (getWordParts word)
+  where
+    f x = case x of
+        T_Literal _ s -> return $ map PGChar s
+        T_SingleQuoted _ s -> return $ map PGChar s
+
+        T_DollarBraced {} -> return [PGMany]
+        T_DollarExpansion {} -> return [PGMany]
+        T_Backticked {} -> return [PGMany]
+
+        T_Glob _ "?" -> return [PGAny]
+        T_Glob _ ('[':_)  -> return [PGAny]
+        T_Glob {} -> return [PGMany]
+
+        T_Extglob {} -> return [PGMany]
+
+        _ -> return [PGMany]
+
+-- Turn a word into a PG pattern, but only if we can preserve
+-- exact semantics.
+wordToExactPseudoGlob :: Token -> Maybe [PseudoGlob]
+wordToExactPseudoGlob word =
+    simplifyPseudoGlob . concat <$> mapM f (getWordParts word)
+  where
+    f x = case x of
+        T_Literal _ s -> return $ map PGChar s
+        T_SingleQuoted _ s -> return $ map PGChar s
+        T_Glob _ "?" -> return [PGAny]
+        T_Glob _ "*" -> return [PGMany]
+        _ -> fail "Unknown token type"
+
+-- Reorder a PseudoGlob for more efficient matching, e.g.
+-- f?*?**g -> f??*g
+simplifyPseudoGlob :: [PseudoGlob] -> [PseudoGlob]
+simplifyPseudoGlob = f
+  where
+    f [] = []
+    f (x@(PGChar _) : rest ) = x : f rest
+    f list =
+        let (anys, rest) = span (\x -> x == PGMany || x == PGAny) list in
+            order anys ++ f rest
+
+    order s = let (any, many) = partition (== PGAny) s in
+        any ++ take 1 many
+
+-- Check whether the two patterns can ever overlap.
+pseudoGlobsCanOverlap :: [PseudoGlob] -> [PseudoGlob] -> Bool
+pseudoGlobsCanOverlap = matchable
+  where
+    matchable x@(xf:xs) y@(yf:ys) =
+        case (xf, yf) of
+            (PGMany, _) -> matchable x ys || matchable xs y
+            (_, PGMany) -> matchable x ys || matchable xs y
+            (PGAny, _) -> matchable xs ys
+            (_, PGAny) -> matchable xs ys
+            (_, _) -> xf == yf && matchable xs ys
+
+    matchable [] [] = True
+    matchable (PGMany : rest) [] = matchable rest []
+    matchable (_:_) [] = False
+    matchable [] r = matchable r []
+
+-- Check whether the first pattern always overlaps the second.
+pseudoGlobIsSuperSetof :: [PseudoGlob] -> [PseudoGlob] -> Bool
+pseudoGlobIsSuperSetof = matchable
+  where
+    matchable x@(xf:xs) y@(yf:ys) =
+        case (xf, yf) of
+            (PGMany, PGMany) -> matchable x ys
+            (PGMany, _) -> matchable x ys || matchable xs y
+            (_, PGMany) -> False
+            (PGAny, _) -> matchable xs ys
+            (_, PGAny) -> False
+            (_, _) -> xf == yf && matchable xs ys
+
+    matchable [] [] = True
+    matchable (PGMany : rest) [] = matchable rest []
+    matchable _ _ = False
+
+wordsCanBeEqual x y = fromMaybe True $
+    liftM2 pseudoGlobsCanOverlap (wordToPseudoGlob x) (wordToPseudoGlob y)
+
+-- Is this an expansion that can be quoted,
+-- e.g. $(foo) `foo` $foo (but not {foo,})?
+isQuoteableExpansion t = case t of
+    T_DollarBraced {} -> True
+    _ -> isCommandSubstitution t
+
+isCommandSubstitution t = case t of
+    T_DollarExpansion {} -> True
+    T_DollarBraceCommandExpansion {} -> True
+    T_Backticked {} -> True
+    _ -> False
+
+
+-- Is this a T_Annotation that ignores a specific code?
+isAnnotationIgnoringCode code t =
+    case t of
+        T_Annotation _ anns _ -> any hasNum anns
+        _ -> False
+  where
+    hasNum (DisableComment ts) = code == ts
+    hasNum _                   = False

src/ShellCheck/Analyzer.hs

@@ -0,0 +1,51 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Analyzer (analyzeScript, ShellCheck.Analyzer.optionalChecks) where
+
+import ShellCheck.Analytics
+import ShellCheck.AnalyzerLib
+import ShellCheck.Interface
+import Data.List
+import Data.Monoid
+import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.Custom
+import qualified ShellCheck.Checks.ShellSupport
+
+
+-- TODO: Clean up the cruft this is layered on
+analyzeScript :: AnalysisSpec -> AnalysisResult
+analyzeScript spec = newAnalysisResult {
+    arComments =
+        filterByAnnotation spec params . nub $
+            runAnalytics spec
+            ++ runChecker params (checkers params)
+}
+  where
+    params = makeParameters spec
+
+checkers params = mconcat $ map ($ params) [
+    ShellCheck.Checks.Commands.checker,
+    ShellCheck.Checks.Custom.checker,
+    ShellCheck.Checks.ShellSupport.checker
+    ]
+
+optionalChecks = mconcat $ [
+    ShellCheck.Analytics.optionalChecks
+    ]

src/ShellCheck/AnalyzerLib.hs

@@ -0,0 +1,974 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE TemplateHaskell  #-}
+module ShellCheck.AnalyzerLib where
+
+import ShellCheck.AST
+import ShellCheck.ASTLib
+import ShellCheck.Data
+import ShellCheck.Interface
+import ShellCheck.Parser
+import ShellCheck.Regex
+
+import Control.Arrow (first)
+import Control.DeepSeq
+import Control.Monad.Identity
+import Control.Monad.RWS
+import Control.Monad.State
+import Control.Monad.Writer
+import Data.Char
+import Data.List
+import Data.Maybe
+import Data.Semigroup
+import qualified Data.Map as Map
+
+import Test.QuickCheck.All (forAllProperties)
+import Test.QuickCheck.Test (maxSuccess, quickCheckWithResult, stdArgs)
+
+type Analysis = AnalyzerM ()
+type AnalyzerM a = RWS Parameters [TokenComment] Cache a
+nullCheck = const $ return ()
+
+
+data Checker = Checker {
+    perScript :: Root -> Analysis,
+    perToken  :: Token -> Analysis
+}
+
+runChecker :: Parameters -> Checker -> [TokenComment]
+runChecker params checker = notes
+    where
+        root = rootNode params
+        check = perScript checker `composeAnalyzers` (\(Root x) -> void $ doAnalysis (perToken checker) x)
+        notes = snd $ evalRWS (check $ Root root) params Cache
+
+instance Semigroup Checker where
+    (<>) x y = Checker {
+        perScript = perScript x `composeAnalyzers` perScript y,
+        perToken = perToken x `composeAnalyzers` perToken y
+        }
+
+instance Monoid Checker where
+    mempty = Checker {
+        perScript = nullCheck,
+        perToken = nullCheck
+        }
+    mappend = (Data.Semigroup.<>)
+
+composeAnalyzers :: (a -> Analysis) -> (a -> Analysis) -> a -> Analysis
+composeAnalyzers f g x = f x >> g x
+
+data Parameters = Parameters {
+    -- Whether this script has the 'lastpipe' option set/default.
+    hasLastpipe        :: Bool,
+    -- Whether this script has 'set -e' anywhere.
+    hasSetE            :: Bool,
+    -- A linear (bad) analysis of data flow
+    variableFlow       :: [StackData],
+    -- A map from Id to parent Token
+    parentMap          :: Map.Map Id Token,
+    -- The shell type, such as Bash or Ksh
+    shellType          :: Shell,
+    -- True if shell type was forced via flags
+    shellTypeSpecified :: Bool,
+    -- The root node of the AST
+    rootNode           :: Token,
+    -- map from token id to start and end position
+    tokenPositions     :: Map.Map Id (Position, Position)
+    } deriving (Show)
+
+-- TODO: Cache results of common AST ops here
+data Cache = Cache {}
+
+data Scope = SubshellScope String | NoneScope deriving (Show, Eq)
+data StackData =
+    StackScope Scope
+    | StackScopeEnd
+    -- (Base expression, specific position, var name, assigned values)
+    | Assignment (Token, Token, String, DataType)
+    | Reference (Token, Token, String)
+  deriving (Show)
+
+data DataType = DataString DataSource | DataArray DataSource
+  deriving (Show)
+
+data DataSource =
+    SourceFrom [Token]
+    | SourceExternal
+    | SourceDeclaration
+    | SourceInteger
+    | SourceChecked
+  deriving (Show)
+
+data VariableState = Dead Token String | Alive deriving (Show)
+
+defaultSpec pr = spec {
+    asShellType = Nothing,
+    asCheckSourced = False,
+    asExecutionMode = Executed,
+    asTokenPositions = prTokenPositions pr
+} where spec = newAnalysisSpec (fromJust $ prRoot pr)
+
+pScript s =
+  let
+    pSpec = newParseSpec {
+        psFilename = "script",
+        psScript = s
+    }
+  in runIdentity $ parseScript (mockedSystemInterface []) pSpec
+
+-- For testing. If parsed, returns whether there are any comments
+producesComments :: Checker -> String -> Maybe Bool
+producesComments c s = do
+        let pr = pScript s
+        prRoot pr
+        let spec = defaultSpec pr
+        let params = makeParameters spec
+        return . not . null $ runChecker params c
+
+makeComment :: Severity -> Id -> Code -> String -> TokenComment
+makeComment severity id code note =
+    newTokenComment {
+        tcId = id,
+        tcComment = newComment {
+            cSeverity = severity,
+            cCode = code,
+            cMessage = note
+        }
+    }
+
+addComment note = note `deepseq` tell [note]
+
+warn :: MonadWriter [TokenComment] m => Id -> Code -> String -> m ()
+warn  id code str = addComment $ makeComment WarningC id code str
+err   id code str = addComment $ makeComment ErrorC id code str
+info  id code str = addComment $ makeComment InfoC id code str
+style id code str = addComment $ makeComment StyleC id code str
+
+warnWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
+warnWithFix  = addCommentWithFix WarningC
+styleWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
+styleWithFix = addCommentWithFix StyleC
+
+addCommentWithFix :: MonadWriter [TokenComment] m => Severity -> Id -> Code -> String -> Fix -> m ()
+addCommentWithFix severity id code str fix =
+    addComment $ makeCommentWithFix severity id code str fix
+
+makeCommentWithFix :: Severity -> Id -> Code -> String -> Fix -> TokenComment
+makeCommentWithFix severity id code str fix =
+    let comment = makeComment severity id code str
+        withFix = comment {
+            tcFix = Just fix
+        }
+    in withFix `deepseq` withFix
+
+makeParameters spec =
+    let params = Parameters {
+        rootNode = root,
+        shellType = fromMaybe (determineShell (asFallbackShell spec) root) $ asShellType spec,
+        hasSetE = containsSetE root,
+        hasLastpipe =
+            case shellType params of
+                Bash -> containsLastpipe root
+                Dash -> False
+                Sh   -> False
+                Ksh  -> True,
+
+        shellTypeSpecified = isJust (asShellType spec) || isJust (asFallbackShell spec),
+        parentMap = getParentTree root,
+        variableFlow = getVariableFlow params root,
+        tokenPositions = asTokenPositions spec
+    } in params
+  where root = asScript spec
+
+
+-- Does this script mention 'set -e' anywhere?
+-- Used as a hack to disable certain warnings.
+containsSetE root = isNothing $ doAnalysis (guard . not . isSetE) root
+  where
+    isSetE t =
+        case t of
+            T_Script _ (T_Literal _ str) _ -> str `matches` re
+            T_SimpleCommand {}  ->
+                t `isUnqualifiedCommand` "set" &&
+                    ("errexit" `elem` oversimplify t ||
+                        "e" `elem` map snd (getAllFlags t))
+            _ -> False
+    re = mkRegex "[[:space:]]-[^-]*e"
+
+-- Does this script mention 'shopt -s lastpipe' anywhere?
+-- Also used as a hack.
+containsLastpipe root =
+        isNothing $ doAnalysis (guard . not . isShoptLastPipe) root
+    where
+        isShoptLastPipe t =
+            case t of
+                T_SimpleCommand {}  ->
+                    t `isUnqualifiedCommand` "shopt" &&
+                        ("lastpipe" `elem` oversimplify t)
+                _ -> False
+
+
+prop_determineShell0 = determineShellTest "#!/bin/sh" == Sh
+prop_determineShell1 = determineShellTest "#!/usr/bin/env ksh" == Ksh
+prop_determineShell2 = determineShellTest "" == Bash
+prop_determineShell3 = determineShellTest "#!/bin/sh -e" == Sh
+prop_determineShell4 = determineShellTest "#!/bin/ksh\n#shellcheck shell=sh\nfoo" == Sh
+prop_determineShell5 = determineShellTest "#shellcheck shell=sh\nfoo" == Sh
+prop_determineShell6 = determineShellTest "#! /bin/sh" == Sh
+prop_determineShell7 = determineShellTest "#! /bin/ash" == Dash
+prop_determineShell8 = determineShellTest' (Just Ksh) "#!/bin/sh" == Sh
+
+determineShellTest = determineShellTest' Nothing
+determineShellTest' fallbackShell = determineShell fallbackShell . fromJust . prRoot . pScript
+determineShell fallbackShell t = fromMaybe Bash $ do
+    shellString <- foldl mplus Nothing $ getCandidates t
+    shellForExecutable shellString `mplus` fallbackShell
+  where
+    forAnnotation t =
+        case t of
+            (ShellOverride s) -> return s
+            _                 -> fail ""
+    getCandidates :: Token -> [Maybe String]
+    getCandidates t@T_Script {} = [Just $ fromShebang t]
+    getCandidates (T_Annotation _ annotations s) =
+        map forAnnotation annotations ++
+           [Just $ fromShebang s]
+    fromShebang (T_Script _ (T_Literal _ s) _) = executableFromShebang s
+
+-- Given a string like "/bin/bash" or "/usr/bin/env dash",
+-- return the shell basename like "bash" or "dash"
+executableFromShebang :: String -> String
+executableFromShebang = shellFor
+  where
+    shellFor s | "/env " `isInfixOf` s = head (drop 1 (words s)++[""])
+    shellFor s | ' ' `elem` s = shellFor $ takeWhile (/= ' ') s
+    shellFor s = reverse . takeWhile (/= '/') . reverse $ s
+
+
+
+-- Given a root node, make a map from Id to parent Token.
+-- This is used to populate parentMap in Parameters
+getParentTree :: Token -> Map.Map Id Token
+getParentTree t =
+    snd . snd $ runState (doStackAnalysis pre post t) ([], Map.empty)
+  where
+    pre t = modify (first ((:) t))
+    post t = do
+        (x, map) <- get
+        case x of
+          _:rest -> case rest of []    -> put (rest, map)
+                                 (x:_) -> put (rest, Map.insert (getId t) x map)
+
+-- Given a root node, make a map from Id to Token
+getTokenMap :: Token -> Map.Map Id Token
+getTokenMap t =
+    execState (doAnalysis f t) Map.empty
+  where
+    f t = modify (Map.insert (getId t) t)
+
+
+-- Is this token in a quoting free context? (i.e. would variable expansion split)
+-- True:  Assignments, [[ .. ]], here docs, already in double quotes
+-- False: Regular words
+isStrictlyQuoteFree = isQuoteFreeNode True
+
+-- Like above, but also allow some cases where splitting may be desired.
+-- True:  Like above + for loops
+-- False: Like above
+isQuoteFree = isQuoteFreeNode False
+
+
+isQuoteFreeNode strict tree t =
+    (isQuoteFreeElement t == Just True) ||
+        head (mapMaybe isQuoteFreeContext (drop 1 $ getPath tree t) ++ [False])
+  where
+    -- Is this node self-quoting in itself?
+    isQuoteFreeElement t =
+        case t of
+            T_Assignment {} -> return True
+            T_FdRedirect {} -> return True
+            _               -> Nothing
+
+    -- Are any subnodes inherently self-quoting?
+    isQuoteFreeContext t =
+        case t of
+            TC_Nullary _ DoubleBracket _    -> return True
+            TC_Unary _ DoubleBracket _ _    -> return True
+            TC_Binary _ DoubleBracket _ _ _ -> return True
+            TA_Sequence {}                  -> return True
+            T_Arithmetic {}                 -> return True
+            T_Assignment {}                 -> return True
+            T_Redirecting {}                -> return False
+            T_DoubleQuoted _ _              -> return True
+            T_DollarDoubleQuoted _ _        -> return True
+            T_CaseExpression {}             -> return True
+            T_HereDoc {}                    -> return True
+            T_DollarBraced {}               -> return True
+            -- When non-strict, pragmatically assume it's desirable to split here
+            T_ForIn {}                      -> return (not strict)
+            T_SelectIn {}                   -> return (not strict)
+            _                               -> Nothing
+
+-- Check if a token is a parameter to a certain command by name:
+-- Example: isParamTo (parentMap params) "sed" t
+isParamTo :: Map.Map Id Token -> String -> Token -> Bool
+isParamTo tree cmd =
+    go
+  where
+    go x = case Map.lookup (getId x) tree of
+                Nothing     -> False
+                Just parent -> check parent
+    check t =
+        case t of
+            T_SingleQuoted _ _ -> go t
+            T_DoubleQuoted _ _ -> go t
+            T_NormalWord _ _   -> go t
+            T_SimpleCommand {} -> isCommand t cmd
+            T_Redirecting {}   -> isCommand t cmd
+            _                  -> False
+
+-- Get the parent command (T_Redirecting) of a Token, if any.
+getClosestCommand :: Map.Map Id Token -> Token -> Maybe Token
+getClosestCommand tree t =
+    findFirst findCommand $ getPath tree t
+  where
+    findCommand t =
+        case t of
+            T_Redirecting {} -> return True
+            T_Script {}      -> return False
+            _                -> Nothing
+
+-- Like above, if koala_man knew Haskell when starting this project.
+getClosestCommandM t = do
+    tree <- asks parentMap
+    return $ getClosestCommand tree t
+
+-- Is the token used as a command name (the first word in a T_SimpleCommand)?
+usedAsCommandName tree token = go (getId token) (tail $ getPath tree token)
+  where
+    go currentId (T_NormalWord id [word]:rest)
+        | currentId == getId word = go id rest
+    go currentId (T_DoubleQuoted id [word]:rest)
+        | currentId == getId word = go id rest
+    go currentId (T_SimpleCommand _ _ (word:_):_)
+        | currentId == getId word = True
+    go _ _ = False
+
+-- A list of the element and all its parents up to the root node.
+getPath tree t = t :
+    case Map.lookup (getId t) tree of
+        Nothing     -> []
+        Just parent -> getPath tree parent
+
+-- Version of the above taking the map from the current context
+-- Todo: give this the name "getPath"
+getPathM t = do
+    map <- asks parentMap
+    return $ getPath map t
+
+isParentOf tree parent child =
+    elem (getId parent) . map getId $ getPath tree child
+
+parents params = getPath (parentMap params)
+
+-- Find the first match in a list where the predicate is Just True.
+-- Stops if it's Just False and ignores Nothing.
+findFirst :: (a -> Maybe Bool) -> [a] -> Maybe a
+findFirst p l =
+    case l of
+        [] -> Nothing
+        (x:xs) ->
+            case p x of
+                Just True  -> return x
+                Just False -> Nothing
+                Nothing    -> findFirst p xs
+
+-- Check whether a word is entirely output from a single command
+tokenIsJustCommandOutput t = case t of
+    T_NormalWord id [T_DollarExpansion _ cmds] -> check cmds
+    T_NormalWord id [T_DoubleQuoted _ [T_DollarExpansion _ cmds]] -> check cmds
+    T_NormalWord id [T_Backticked _ cmds] -> check cmds
+    T_NormalWord id [T_DoubleQuoted _ [T_Backticked _ cmds]] -> check cmds
+    _ -> False
+  where
+    check [x] = not $ isOnlyRedirection x
+    check _   = False
+
+-- TODO: Replace this with a proper Control Flow Graph
+getVariableFlow params t =
+    let (_, stack) = runState (doStackAnalysis startScope endScope t) []
+    in reverse stack
+  where
+    startScope t =
+        let scopeType = leadType params t
+        in do
+            when (scopeType /= NoneScope) $ modify (StackScope scopeType:)
+            when (assignFirst t) $ setWritten t
+
+    endScope t =
+        let scopeType = leadType params t
+        in do
+            setRead t
+            unless (assignFirst t) $ setWritten t
+            when (scopeType /= NoneScope) $ modify (StackScopeEnd:)
+
+    assignFirst T_ForIn {}    = True
+    assignFirst T_SelectIn {} = True
+    assignFirst (T_BatsTest {}) = True
+    assignFirst _             = False
+
+    setRead t =
+        let read    = getReferencedVariables (parentMap params) t
+        in mapM_ (\v -> modify (Reference v:)) read
+
+    setWritten t =
+        let written = getModifiedVariables t
+        in mapM_ (\v -> modify (Assignment v:)) written
+
+
+leadType params t =
+    case t of
+        T_DollarExpansion _ _  -> SubshellScope "$(..) expansion"
+        T_Backticked _ _  -> SubshellScope "`..` expansion"
+        T_Backgrounded _ _  -> SubshellScope "backgrounding &"
+        T_Subshell _ _  -> SubshellScope "(..) group"
+        T_BatsTest {} -> SubshellScope "@bats test"
+        T_CoProcBody _ _  -> SubshellScope "coproc"
+        T_Redirecting {}  ->
+            if fromMaybe False causesSubshell
+            then SubshellScope "pipeline"
+            else NoneScope
+        _ -> NoneScope
+  where
+    parentPipeline = do
+        parent <- Map.lookup (getId t) (parentMap params)
+        case parent of
+            T_Pipeline {} -> return parent
+            _             -> Nothing
+
+    causesSubshell = do
+        (T_Pipeline _ _ list) <- parentPipeline
+        if length list <= 1
+            then return False
+            else if not $ hasLastpipe params
+                then return True
+                else return . not $ (getId . head $ reverse list) == getId t
+
+getModifiedVariables t =
+    case t of
+        T_SimpleCommand _ vars [] ->
+            concatMap (\x -> case x of
+                                T_Assignment id _ name _ w  ->
+                                    [(x, x, name, dataTypeFrom DataString w)]
+                                _ -> []
+                      ) vars
+        c@T_SimpleCommand {} ->
+            getModifiedVariableCommand c
+
+        TA_Unary _ "++|" v@(TA_Variable _ name _)  ->
+            [(t, v, name, DataString $ SourceFrom [v])]
+        TA_Unary _ "|++" v@(TA_Variable _ name _)  ->
+            [(t, v, name, DataString $ SourceFrom [v])]
+        TA_Assignment _ op (TA_Variable _ name _) rhs -> maybeToList $ do
+            guard $ op `elem` ["=", "*=", "/=", "%=", "+=", "-=", "<<=", ">>=", "&=", "^=", "|="]
+            return (t, t, name, DataString $ SourceFrom [rhs])
+
+        T_BatsTest {} -> [
+            (t, t, "lines", DataArray SourceExternal),
+            (t, t, "status", DataString SourceInteger),
+            (t, t, "output", DataString SourceExternal)
+            ]
+
+        -- Count [[ -v foo ]] as an "assignment".
+        -- This is to prevent [ -v foo ] being unassigned or unused.
+        TC_Unary id _ "-v" token -> maybeToList $ do
+            str <- fmap (takeWhile (/= '[')) $ -- Quoted index
+                    flip getLiteralStringExt token $ \x ->
+                case x of
+                    T_Glob _ s -> return s -- Unquoted index
+                    _          -> Nothing
+
+            guard . not . null $ str
+            return (t, token, str, DataString SourceChecked)
+
+        T_DollarBraced _ _ l -> maybeToList $ do
+            let string = bracedString t
+            let modifier = getBracedModifier string
+            guard $ ":=" `isPrefixOf` modifier
+            return (t, t, getBracedReference string, DataString $ SourceFrom [l])
+
+        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&2 modifies foo
+            [(t, t, takeWhile (/= '}') var, DataString SourceInteger) | not $ isClosingFileOp op]
+
+        t@(T_CoProc _ name _) ->
+            [(t, t, fromMaybe "COPROC" name, DataArray SourceInteger)]
+
+        --Points to 'for' rather than variable
+        T_ForIn id str [] _ -> [(t, t, str, DataString SourceExternal)]
+        T_ForIn id str words _ -> [(t, t, str, DataString $ SourceFrom words)]
+        T_SelectIn id str words _ -> [(t, t, str, DataString $ SourceFrom words)]
+        _ -> []
+
+isClosingFileOp op =
+    case op of
+        T_IoDuplicate _ (T_GREATAND _) "-" -> True
+        T_IoDuplicate _ (T_LESSAND  _) "-" -> True
+        _                                  -> False
+
+
+-- Consider 'export/declare -x' a reference, since it makes the var available
+getReferencedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal _ x:_):rest)) =
+    case x of
+        "export" -> if "f" `elem` flags
+            then []
+            else concatMap getReference rest
+        "declare" -> if
+                any (`elem` flags) ["x", "p"] &&
+                    (not $ any (`elem` flags) ["f", "F"])
+            then concatMap getReference rest
+            else []
+        "trap" ->
+            case rest of
+                head:_ -> map (\x -> (head, head, x)) $ getVariablesFromLiteralToken head
+                _ -> []
+        _ -> []
+  where
+    getReference t@(T_Assignment _ _ name _ value) = [(t, t, name)]
+    getReference t@(T_NormalWord _ [T_Literal _ name]) | not ("-" `isPrefixOf` name) = [(t, t, name)]
+    getReference _ = []
+    flags = map snd $ getAllFlags base
+
+getReferencedVariableCommand _ = []
+
+-- The function returns a tuple consisting of four items describing an assignment.
+-- Given e.g. declare foo=bar
+-- (
+--   BaseCommand :: Token,     -- The command/structure assigning the variable, i.e. declare foo=bar
+--   AssignmentToken :: Token, -- The specific part that assigns this variable, i.e. foo=bar
+--   VariableName :: String,   -- The variable name, i.e. foo
+--   VariableValue :: DataType -- A description of the value being assigned, i.e. "Literal string with value foo"
+-- )
+getModifiedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal _ x:_):rest)) =
+   filter (\(_,_,s,_) -> not ("-" `isPrefixOf` s)) $
+    case x of
+        "read" ->
+            let params = map getLiteral rest
+                readArrayVars = getReadArrayVariables rest
+            in
+                catMaybes . (++ readArrayVars) . takeWhile isJust . reverse $ params
+        "getopts" ->
+            case rest of
+                opts:var:_ -> maybeToList $ getLiteral var
+                _          -> []
+
+        "let" -> concatMap letParamToLiteral rest
+
+        "export" ->
+            if "f" `elem` flags then [] else concatMap getModifierParamString rest
+
+        "declare" -> if any (`elem` flags) ["F", "f", "p"] then [] else declaredVars
+        "typeset" -> declaredVars
+
+        "local" -> concatMap getModifierParamString rest
+        "readonly" ->
+            if any (`elem` flags) ["f", "p"]
+            then []
+            else concatMap getModifierParamString rest
+        "set" -> maybeToList $ do
+            params <- getSetParams rest
+            return (base, base, "@", DataString $ SourceFrom params)
+
+        "printf" -> maybeToList $ getPrintfVariable rest
+
+        "mapfile" -> maybeToList $ getMapfileArray base rest
+        "readarray" -> maybeToList $ getMapfileArray base rest
+
+        "DEFINE_boolean" -> maybeToList $ getFlagVariable rest
+        "DEFINE_float" -> maybeToList $ getFlagVariable rest
+        "DEFINE_integer" -> maybeToList $ getFlagVariable rest
+        "DEFINE_string" -> maybeToList $ getFlagVariable rest
+
+        _ -> []
+  where
+    flags = map snd $ getAllFlags base
+    stripEquals s = let rest = dropWhile (/= '=') s in
+        if rest == "" then "" else tail rest
+    stripEqualsFrom (T_NormalWord id1 (T_Literal id2 s:rs)) =
+        T_NormalWord id1 (T_Literal id2 (stripEquals s):rs)
+    stripEqualsFrom (T_NormalWord id1 [T_DoubleQuoted id2 [T_Literal id3 s]]) =
+        T_NormalWord id1 [T_DoubleQuoted id2 [T_Literal id3 (stripEquals s)]]
+    stripEqualsFrom t = t
+
+    declaredVars = concatMap (getModifierParam defaultType) rest
+      where
+        defaultType = if any (`elem` flags) ["a", "A"] then DataArray else DataString
+
+    getLiteralOfDataType t d = do
+        s <- getLiteralString t
+        when ("-" `isPrefixOf` s) $ fail "argument"
+        return (base, t, s, d)
+
+    getLiteral t = getLiteralOfDataType t (DataString SourceExternal)
+
+    getLiteralArray t = getLiteralOfDataType t (DataArray SourceExternal)
+
+    getModifierParamString = getModifierParam DataString
+
+    getModifierParam def t@(T_Assignment _ _ name _ value) =
+        [(base, t, name, dataTypeFrom def value)]
+    getModifierParam def t@T_NormalWord {} = maybeToList $ do
+        name <- getLiteralString t
+        guard $ isVariableName name
+        return (base, t, name, def SourceDeclaration)
+    getModifierParam _ _ = []
+
+    letParamToLiteral token =
+          if var == ""
+            then []
+            else [(base, token, var, DataString $ SourceFrom [stripEqualsFrom token])]
+        where var = takeWhile isVariableChar $ dropWhile (`elem` "+-") $ concat $ oversimplify token
+
+    getSetParams (t:_:rest) | getLiteralString t == Just "-o" = getSetParams rest
+    getSetParams (t:rest) =
+        let s = getLiteralString t in
+            case s of
+                Just "--"    -> return rest
+                Just ('-':_) -> getSetParams rest
+                _            -> return (t:fromMaybe [] (getSetParams rest))
+    getSetParams [] = Nothing
+
+    getPrintfVariable list = f $ map (\x -> (x, getLiteralString x)) list
+      where
+        f ((_, Just "-v") : (t, Just var) : _) = return (base, t, varName, varType $ SourceFrom list)
+            where
+                (varName, varType) = case elemIndex '[' var of
+                    Just i -> (take i var, DataArray)
+                    Nothing -> (var, DataString)
+        f (_:rest) = f rest
+        f [] = fail "not found"
+
+    -- mapfile has some curious syntax allowing flags plus 0..n variable names
+    -- where only the first non-option one is used if any. Here we cheat and
+    -- just get the last one, if it's a variable name.
+    getMapfileArray base arguments = do
+        lastArg <- listToMaybe (reverse arguments)
+        name <- getLiteralString lastArg
+        guard $ isVariableName name
+        return (base, lastArg, name, DataArray SourceExternal)
+
+    -- get all the array variables used in read, e.g. read -a arr
+    getReadArrayVariables args =
+        map (getLiteralArray . snd)
+            (filter (isArrayFlag . fst) (zip args (tail args)))
+
+    isArrayFlag x = fromMaybe False $ do
+        str <- getLiteralString x
+        return $ case str of
+                    '-':'-':_ -> False
+                    '-':str -> 'a' `elem` str
+                    _ -> False
+
+    -- get the FLAGS_ variable created by a shflags DEFINE_ call
+    getFlagVariable (n:v:_) = do
+        name <- getLiteralString n
+        return (base, n, "FLAGS_" ++ name, DataString $ SourceExternal)
+    getFlagVariable _ = Nothing
+
+getModifiedVariableCommand _ = []
+
+getIndexReferences s = fromMaybe [] $ do
+    match <- matchRegex re s
+    index <- match !!! 0
+    return $ matchAllStrings variableNameRegex index
+  where
+    re = mkRegex "(\\[.*\\])"
+
+prop_getOffsetReferences1 = getOffsetReferences ":bar" == ["bar"]
+prop_getOffsetReferences2 = getOffsetReferences ":bar:baz" == ["bar", "baz"]
+prop_getOffsetReferences3 = getOffsetReferences "[foo]:bar" == ["bar"]
+prop_getOffsetReferences4 = getOffsetReferences "[foo]:bar:baz" == ["bar", "baz"]
+getOffsetReferences mods = fromMaybe [] $ do
+-- if mods start with [, then drop until ]
+    match <- matchRegex re mods
+    offsets <- match !!! 1
+    return $ matchAllStrings variableNameRegex offsets
+  where
+    re = mkRegex "^(\\[.+\\])? *:([^-=?+].*)"
+
+getReferencedVariables parents t =
+    case t of
+        T_DollarBraced id _ l -> let str = bracedString t in
+            (t, t, getBracedReference str) :
+                map (\x -> (l, l, x)) (
+                    getIndexReferences str
+                    ++ getOffsetReferences (getBracedModifier str))
+        TA_Variable id name _ ->
+            if isArithmeticAssignment t
+            then []
+            else [(t, t, name)]
+        T_Assignment id mode str _ word ->
+            [(t, t, str) | mode == Append] ++ specialReferences str t word
+
+        TC_Unary id _ "-v" token -> getIfReference t token
+        TC_Unary id _ "-R" token -> getIfReference t token
+        TC_Binary id DoubleBracket op lhs rhs ->
+            if isDereferencing op
+            then concatMap (getIfReference t) [lhs, rhs]
+            else []
+
+        T_BatsTest {} -> [ -- pretend @test references vars to avoid warnings
+            (t, t, "lines"),
+            (t, t, "status"),
+            (t, t, "output")
+            ]
+
+        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&- references and closes foo
+            [(t, t, takeWhile (/= '}') var) | isClosingFileOp op]
+        x -> getReferencedVariableCommand x
+  where
+    -- Try to reduce false positives for unused vars only referenced from evaluated vars
+    specialReferences name base word =
+        if name `elem` [
+            "PS1", "PS2", "PS3", "PS4",
+            "PROMPT_COMMAND"
+          ]
+        then
+            map (\x -> (base, base, x)) $
+                getVariablesFromLiteralToken word
+        else []
+
+    literalizer t = case t of
+        T_Glob _ s -> return s    -- Also when parsed as globs
+        _          -> Nothing
+
+    getIfReference context token = maybeToList $ do
+            str <- getLiteralStringExt literalizer token
+            guard . not $ null str
+            when (isDigit $ head str) $ fail "is a number"
+            return (context, token, getBracedReference str)
+
+    isDereferencing = (`elem` ["-eq", "-ne", "-lt", "-le", "-gt", "-ge"])
+
+    isArithmeticAssignment t = case getPath parents t of
+        this: TA_Assignment _ "=" lhs _ :_ -> lhs == t
+        _                                  -> False
+
+dataTypeFrom defaultType v = (case v of T_Array {} -> DataArray; _ -> defaultType) $ SourceFrom [v]
+
+
+--- Command specific checks
+
+-- Compare a command to a string: t `isCommand` "sed" (also matches /usr/bin/sed)
+isCommand token str = isCommandMatch token (\cmd -> cmd  == str || ('/' : str) `isSuffixOf` cmd)
+
+-- Compare a command to a literal. Like above, but checks full path.
+isUnqualifiedCommand token str = isCommandMatch token (== str)
+
+isCommandMatch token matcher = fromMaybe False $
+    fmap matcher (getCommandName token)
+
+-- Does this regex look like it was intended as a glob?
+-- True:  *foo*
+-- False: .*foo.*
+isConfusedGlobRegex :: String -> Bool
+isConfusedGlobRegex ('*':_) = True
+isConfusedGlobRegex [x,'*'] | x `notElem` "\\." = True
+isConfusedGlobRegex _       = False
+
+isVariableStartChar x = x == '_' || isAsciiLower x || isAsciiUpper x
+isVariableChar x = isVariableStartChar x || isDigit x
+variableNameRegex = mkRegex "[_a-zA-Z][_a-zA-Z0-9]*"
+
+prop_isVariableName1 = isVariableName "_fo123"
+prop_isVariableName2 = not $ isVariableName "4"
+prop_isVariableName3 = not $ isVariableName "test: "
+isVariableName (x:r) = isVariableStartChar x && all isVariableChar r
+isVariableName _     = False
+
+getVariablesFromLiteralToken token =
+    getVariablesFromLiteral (fromJust $ getLiteralStringExt (const $ return " ") token)
+
+-- Try to get referenced variables from a literal string like "$foo"
+-- Ignores tons of cases like arithmetic evaluation and array indices.
+prop_getVariablesFromLiteral1 =
+    getVariablesFromLiteral "$foo${bar//a/b}$BAZ" == ["foo", "bar", "BAZ"]
+getVariablesFromLiteral string =
+    map (!! 0) $ matchAllSubgroups variableRegex string
+  where
+    variableRegex = mkRegex "\\$\\{?([A-Za-z0-9_]+)"
+
+-- Get the variable name from an expansion like ${var:-foo}
+prop_getBracedReference1 = getBracedReference "foo" == "foo"
+prop_getBracedReference2 = getBracedReference "#foo" == "foo"
+prop_getBracedReference3 = getBracedReference "#" == "#"
+prop_getBracedReference4 = getBracedReference "##" == "#"
+prop_getBracedReference5 = getBracedReference "#!" == "!"
+prop_getBracedReference6 = getBracedReference "!#" == "#"
+prop_getBracedReference7 = getBracedReference "!foo#?" == "foo"
+prop_getBracedReference8 = getBracedReference "foo-bar" == "foo"
+prop_getBracedReference9 = getBracedReference "foo:-bar" == "foo"
+prop_getBracedReference10= getBracedReference "foo: -1" == "foo"
+prop_getBracedReference11= getBracedReference "!os*" == ""
+prop_getBracedReference12= getBracedReference "!os?bar**" == ""
+prop_getBracedReference13= getBracedReference "foo[bar]" == "foo"
+getBracedReference s = fromMaybe s $
+    nameExpansion s `mplus` takeName noPrefix `mplus` getSpecial noPrefix `mplus` getSpecial s
+  where
+    noPrefix = dropPrefix s
+    dropPrefix (c:rest) = if c `elem` "!#" then rest else c:rest
+    dropPrefix ""       = ""
+    takeName s = do
+        let name = takeWhile isVariableChar s
+        guard . not $ null name
+        return name
+    getSpecial (c:_) =
+        if c `elem` "*@#?-$!" then return [c] else fail "not special"
+    getSpecial _ = fail "empty"
+
+    nameExpansion ('!':rest) = do -- e.g. ${!foo*bar*}
+        let suffix = dropWhile isVariableChar rest
+        guard $ suffix /= rest -- e.g. ${!@}
+        first <- suffix !!! 0
+        guard $ first `elem` "*?"
+        return ""
+    nameExpansion _ = Nothing
+
+prop_getBracedModifier1 = getBracedModifier "foo:bar:baz" == ":bar:baz"
+prop_getBracedModifier2 = getBracedModifier "!var:-foo" == ":-foo"
+prop_getBracedModifier3 = getBracedModifier "foo[bar]" == "[bar]"
+getBracedModifier s = fromMaybe "" . listToMaybe $ do
+    let var = getBracedReference s
+    a <- dropModifier s
+    dropPrefix var a
+  where
+    dropPrefix [] t        = return t
+    dropPrefix (a:b) (c:d) | a == c = dropPrefix b d
+    dropPrefix _ _         = []
+
+    dropModifier (c:rest) | c `elem` "#!" = [rest, c:rest]
+    dropModifier x        = [x]
+
+-- Useful generic functions.
+
+-- Run an action in a Maybe (or do nothing).
+-- Example:
+-- potentially $ do
+--   s <- getLiteralString cmd
+--   guard $ s `elem` ["--recursive", "-r"]
+--   return $ warn .. "Something something recursive"
+potentially :: Monad m => Maybe (m ()) -> m ()
+potentially = fromMaybe (return ())
+
+-- Get element 0 or a default. Like `head` but safe.
+headOrDefault _ (a:_) = a
+headOrDefault def _   = def
+
+--- Get element n of a list, or Nothing. Like `!!` but safe.
+(!!!) list i =
+    case drop i list of
+        []    -> Nothing
+        (r:_) -> Just r
+
+-- Run a command if the shell is in the given list
+whenShell l c = do
+    shell <- asks shellType
+    when (shell `elem` l ) c
+
+
+filterByAnnotation asSpec params =
+    filter (not . shouldIgnore)
+  where
+    token = asScript asSpec
+    shouldIgnore note =
+        any (shouldIgnoreFor (getCode note)) $
+            getPath parents (T_Bang $ tcId note)
+    shouldIgnoreFor _ T_Include {} = not $ asCheckSourced asSpec
+    shouldIgnoreFor code t = isAnnotationIgnoringCode code t
+    parents = parentMap params
+    getCode = cCode . tcComment
+
+shouldIgnoreCode params code t =
+    any (isAnnotationIgnoringCode code) $
+        getPath (parentMap params) t
+
+-- Is this a ${#anything}, to get string length or array count?
+isCountingReference (T_DollarBraced id _ token) =
+    case concat $ oversimplify token of
+        '#':_ -> True
+        _     -> False
+isCountingReference _ = False
+
+-- FIXME: doesn't handle ${a:+$var} vs ${a:+"$var"}
+isQuotedAlternativeReference t =
+    case t of
+        T_DollarBraced _ _ _ ->
+            getBracedModifier (bracedString t) `matches` re
+        _ -> False
+  where
+    re = mkRegex "(^|\\]):?\\+"
+
+-- getGnuOpts "erd:u:" will parse a SimpleCommand like
+--     read -re -d : -u 3 bar
+-- into
+--     Just [("r", -re), ("e", -re), ("d", :), ("u", 3), ("", bar)]
+-- where flags with arguments map to arguments, while others map to themselves.
+-- Any unrecognized flag will result in Nothing.
+getGnuOpts = getOpts getAllFlags
+getBsdOpts = getOpts getLeadingFlags
+getOpts :: (Token -> [(Token, String)]) -> String -> Token -> Maybe [(String, Token)]
+getOpts flagTokenizer string cmd = process flags
+  where
+    flags = flagTokenizer cmd
+    flagList (c:':':rest) = ([c], True) : flagList rest
+    flagList (c:rest)     = ([c], False) : flagList rest
+    flagList []           = []
+    flagMap = Map.fromList $ ("", False) : flagList string
+
+    process [] = return []
+    process [(token, flag)] = do
+        takesArg <- Map.lookup flag flagMap
+        guard $ not takesArg
+        return [(flag, token)]
+    process ((token1, flag1):rest2@((token2, flag2):rest)) = do
+        takesArg <- Map.lookup flag1 flagMap
+        if takesArg
+            then do
+                guard $ flag2 == ""
+                more <- process rest
+                return $ (flag1, token2) : more
+            else do
+                more <- process rest2
+                return $ (flag1, token1) : more
+
+supportsArrays shell = shell == Bash || shell == Ksh
+
+-- Returns true if the shell is Bash or Ksh (sorry for the name, Ksh)
+isBashLike :: Parameters -> Bool
+isBashLike params =
+    case shellType params of
+        Bash -> True
+        Ksh -> True
+        Dash -> False
+        Sh -> False
+
+return []
+runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Checker.hs

@@ -0,0 +1,394 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE TemplateHaskell #-}
+module ShellCheck.Checker (checkScript, ShellCheck.Checker.runTests) where
+
+import ShellCheck.Interface
+import ShellCheck.Parser
+import ShellCheck.Analyzer
+
+import Data.Either
+import Data.Functor
+import Data.List
+import Data.Maybe
+import Data.Ord
+import Control.Monad.Identity
+import qualified Data.Map as Map
+import qualified System.IO
+import Prelude hiding (readFile)
+import Control.Monad
+
+import Test.QuickCheck.All
+
+tokenToPosition startMap t = fromMaybe fail $ do
+    span <- Map.lookup (tcId t) startMap
+    return $ newPositionedComment {
+        pcStartPos = fst span,
+        pcEndPos = snd span,
+        pcComment = tcComment t,
+        pcFix = tcFix t
+    }
+  where
+    fail = error "Internal shellcheck error: id doesn't exist. Please report!"
+
+shellFromFilename filename = foldl mplus Nothing candidates
+  where
+    shellExtensions = [(".ksh", Ksh)
+                      ,(".bash", Bash)
+                      ,(".bats", Bash)
+                      ,(".dash", Dash)]
+                      -- The `.sh` is too generic to determine the shell:
+                      -- We fallback to Bash in this case and emit SC2148 if there is no shebang
+    candidates =
+        map (\(ext,sh) -> if ext `isSuffixOf` filename then Just sh else Nothing) shellExtensions
+
+checkScript :: Monad m => SystemInterface m -> CheckSpec -> m CheckResult
+checkScript sys spec = do
+    results <- checkScript (csScript spec)
+    return emptyCheckResult {
+        crFilename = csFilename spec,
+        crComments = results
+    }
+  where
+    checkScript contents = do
+        result <- parseScript sys newParseSpec {
+            psFilename = csFilename spec,
+            psScript = contents,
+            psCheckSourced = csCheckSourced spec,
+            psIgnoreRC = csIgnoreRC spec,
+            psShellTypeOverride = csShellTypeOverride spec
+        }
+        let parseMessages = prComments result
+        let tokenPositions = prTokenPositions result
+        let analysisSpec root =
+                as {
+                    asScript = root,
+                    asShellType = csShellTypeOverride spec,
+                    asFallbackShell = shellFromFilename $ csFilename spec,
+                    asCheckSourced = csCheckSourced spec,
+                    asExecutionMode = Executed,
+                    asTokenPositions = tokenPositions,
+                    asOptionalChecks = csOptionalChecks spec
+                } where as = newAnalysisSpec root
+        let analysisMessages =
+                fromMaybe [] $
+                    (arComments . analyzeScript . analysisSpec)
+                        <$> prRoot result
+        let translator = tokenToPosition tokenPositions
+        return . nub . sortMessages . filter shouldInclude $
+            (parseMessages ++ map translator analysisMessages)
+
+    shouldInclude pc =
+            severity <= csMinSeverity spec &&
+            case csIncludedWarnings spec of
+                Nothing -> code `notElem` csExcludedWarnings spec
+                Just includedWarnings -> code `elem` includedWarnings
+        where
+            code     = cCode (pcComment pc)
+            severity = cSeverity (pcComment pc)
+
+    sortMessages = sortBy (comparing order)
+    order pc =
+        let pos = pcStartPos pc
+            comment = pcComment pc in
+        (posFile pos,
+         posLine pos,
+         posColumn pos,
+         cSeverity comment,
+         cCode comment,
+         cMessage comment)
+    getPosition = pcStartPos
+
+
+getErrors sys spec =
+    sort . map getCode . crComments $
+        runIdentity (checkScript sys spec)
+  where
+    getCode = cCode . pcComment
+
+check = checkWithIncludes []
+
+checkWithSpec includes =
+    getErrors (mockedSystemInterface includes)
+
+checkWithIncludes includes src =
+    checkWithSpec includes emptyCheckSpec {
+        csScript = src,
+        csExcludedWarnings = [2148]
+    }
+
+checkRecursive includes src =
+    checkWithSpec includes emptyCheckSpec {
+        csScript = src,
+        csExcludedWarnings = [2148],
+        csCheckSourced = True
+    }
+
+checkOptionIncludes includes src =
+    checkWithSpec [] emptyCheckSpec {
+        csScript = src,
+        csIncludedWarnings = includes,
+        csCheckSourced = True
+    }
+
+checkWithRc rc = getErrors
+    (mockRcFile rc $ mockedSystemInterface [])
+
+checkWithIncludesAndSourcePath includes mapper = getErrors
+    (mockedSystemInterface includes) {
+        siFindSource = mapper
+    }
+
+prop_findsParseIssue = check "echo \"$12\"" == [1037]
+
+prop_commentDisablesParseIssue1 =
+    null $ check "#shellcheck disable=SC1037\necho \"$12\""
+prop_commentDisablesParseIssue2 =
+    null $ check "#shellcheck disable=SC1037\n#lol\necho \"$12\""
+
+prop_findsAnalysisIssue =
+    check "echo $1" == [2086]
+prop_commentDisablesAnalysisIssue1 =
+    null $ check "#shellcheck disable=SC2086\necho $1"
+prop_commentDisablesAnalysisIssue2 =
+    null $ check "#shellcheck disable=SC2086\n#lol\necho $1"
+
+prop_optionDisablesIssue1 =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "echo $1",
+                    csExcludedWarnings = [2148, 2086]
+                }
+
+prop_optionDisablesIssue2 =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "echo \"$10\"",
+                    csExcludedWarnings = [2148, 1037]
+                }
+
+prop_wontParseBadShell =
+    [1071] == check "#!/usr/bin/python\ntrue $1\n"
+
+prop_optionDisablesBadShebang =
+    null $ getErrors
+                (mockedSystemInterface [])
+                emptyCheckSpec {
+                    csScript = "#!/usr/bin/python\ntrue\n",
+                    csShellTypeOverride = Just Sh
+                }
+
+prop_annotationDisablesBadShebang =
+    [] == check "#!/usr/bin/python\n# shellcheck shell=sh\ntrue\n"
+
+
+prop_canParseDevNull =
+    [] == check "source /dev/null"
+
+prop_failsWhenNotSourcing =
+    [1091, 2154] == check "source lol; echo \"$bar\""
+
+prop_worksWhenSourcing =
+    null $ checkWithIncludes [("lib", "bar=1")] "source lib; echo \"$bar\""
+
+prop_worksWhenSourcingWithDashDash =
+    null $ checkWithIncludes [("lib", "bar=1")] "source -- lib; echo \"$bar\""
+
+prop_worksWhenDotting =
+    null $ checkWithIncludes [("lib", "bar=1")] ". lib; echo \"$bar\""
+
+-- FIXME: This should really be giving [1093], "recursively sourced"
+prop_noInfiniteSourcing =
+    [] == checkWithIncludes  [("lib", "source lib")] "source lib"
+
+prop_canSourceBadSyntax =
+    [1094, 2086] == checkWithIncludes [("lib", "for f; do")] "source lib; echo $1"
+
+prop_cantSourceDynamic =
+    [1090] == checkWithIncludes [("lib", "")] ". \"$1\""
+
+prop_cantSourceDynamic2 =
+    [1090] == checkWithIncludes [("lib", "")] "source ~/foo"
+
+prop_canSourceDynamicWhenRedirected =
+    null $ checkWithIncludes [("lib", "")] "#shellcheck source=lib\n. \"$1\""
+
+prop_recursiveAnalysis =
+    [2086] == checkRecursive [("lib", "echo $1")] "source lib"
+
+prop_recursiveParsing =
+    [1037] == checkRecursive [("lib", "echo \"$10\"")] "source lib"
+
+prop_nonRecursiveAnalysis =
+    [] == checkWithIncludes [("lib", "echo $1")] "source lib"
+
+prop_nonRecursiveParsing =
+    [] == checkWithIncludes [("lib", "echo \"$10\"")] "source lib"
+
+prop_sourceDirectiveDoesntFollowFile =
+    null $ checkWithIncludes
+                [("foo", "source bar"), ("bar", "baz=3")]
+                "#shellcheck source=foo\n. \"$1\"; echo \"$baz\""
+
+prop_filewideAnnotationBase = [2086] == check "#!/bin/sh\necho $1"
+prop_filewideAnnotation1 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\necho $1"
+prop_filewideAnnotation2 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation3 = null $
+    check "#!/bin/sh\n#unrelated\n# shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation4 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\n#unrelated\ntrue\necho $1"
+prop_filewideAnnotation5 = null $
+    check "#!/bin/sh\n\n\n\n#shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation6 = null $
+    check "#shellcheck shell=sh\n#unrelated\n#shellcheck disable=2086\ntrue\necho $1"
+prop_filewideAnnotation7 = null $
+    check "#!/bin/sh\n# shellcheck disable=2086\n#unrelated\ntrue\necho $1"
+
+prop_filewideAnnotationBase2 = [2086, 2181] == check "true\n[ $? == 0 ] && echo $1"
+prop_filewideAnnotation8 = null $
+    check "# Disable $? warning\n#shellcheck disable=SC2181\n# Disable quoting warning\n#shellcheck disable=2086\ntrue\n[ $? == 0 ] && echo $1"
+
+prop_sourcePartOfOriginalScript = -- #1181: -x disabled posix warning for 'source'
+    2039 `elem` checkWithIncludes [("./saywhat.sh", "echo foo")] "#!/bin/sh\nsource ./saywhat.sh"
+
+prop_spinBug1413 = null $ check "fun() {\n# shellcheck disable=SC2188\n> /dev/null\n}\n"
+
+prop_deducesTypeFromExtension = null result
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.ksh",
+        csScript = "(( 3.14 ))"
+    }
+
+prop_deducesTypeFromExtension2 = result == [2079]
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.bash",
+        csScript = "(( 3.14 ))"
+    }
+
+prop_shExtensionDoesntMatter = result == [2148]
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.sh",
+        csScript = "echo 'hello world'"
+    }
+
+prop_sourcedFileUsesOriginalShellExtension = result == [2079]
+  where
+    result = checkWithSpec [("file.ksh", "(( 3.14 ))")] emptyCheckSpec {
+        csFilename = "file.bash",
+        csScript = "source file.ksh",
+        csCheckSourced = True
+    }
+
+prop_canEnableOptionalsWithSpec = result == [2244]
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.sh",
+        csScript = "#!/bin/sh\n[ \"$1\" ]",
+        csOptionalChecks = ["avoid-nullary-conditions"]
+    }
+
+prop_optionIncludes1 =
+    -- expect 2086, but not included, so nothing reported
+    null $ checkOptionIncludes (Just [2080]) "#!/bin/sh\n var='a b'\n echo $var"
+
+prop_optionIncludes2 =
+    -- expect 2086, included, so it is reported
+    [2086] == checkOptionIncludes (Just [2086]) "#!/bin/sh\n var='a b'\n echo $var"
+
+prop_optionIncludes3 =
+    -- expect 2086, no inclusions provided, so it is reported
+    [2086] == checkOptionIncludes Nothing "#!/bin/sh\n var='a b'\n echo $var"
+
+prop_optionIncludes4 =
+    -- expect 2086 & 2154, only 2154 included, so only that's reported
+    [2154] == checkOptionIncludes (Just [2154]) "#!/bin/sh\n var='a b'\n echo $var\n echo $bar"
+
+
+prop_readsRcFile = result == []
+  where
+    result = checkWithRc "disable=2086" emptyCheckSpec {
+        csScript = "#!/bin/sh\necho $1",
+        csIgnoreRC = False
+    }
+
+prop_canUseNoRC = result == [2086]
+  where
+    result = checkWithRc "disable=2086" emptyCheckSpec {
+        csScript = "#!/bin/sh\necho $1",
+        csIgnoreRC = True
+    }
+
+prop_NoRCWontLookAtFile = result == [2086]
+  where
+    result = checkWithRc (error "Fail") emptyCheckSpec {
+        csScript = "#!/bin/sh\necho $1",
+        csIgnoreRC = True
+    }
+
+prop_brokenRcGetsWarning = result == [1134, 2086]
+  where
+    result = checkWithRc "rofl" emptyCheckSpec {
+        csScript = "#!/bin/sh\necho $1",
+        csIgnoreRC = False
+    }
+
+prop_canEnableOptionalsWithRc = result == [2244]
+  where
+    result = checkWithRc "enable=avoid-nullary-conditions" emptyCheckSpec {
+        csScript = "#!/bin/sh\n[ \"$1\" ]"
+    }
+
+prop_sourcePathRedirectsName = result == [2086]
+  where
+    f "dir/myscript" _ "lib" = return "foo/lib"
+    result = checkWithIncludesAndSourcePath [("foo/lib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\nsource lib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_sourcePathAddsAnnotation = result == [2086]
+  where
+    f "dir/myscript" ["mypath"] "lib" = return "foo/lib"
+    result = checkWithIncludesAndSourcePath [("foo/lib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\n# shellcheck source-path=mypath\nsource lib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_sourcePathRedirectsDirective = result == [2086]
+  where
+    f "dir/myscript" _ "lib" = return "foo/lib"
+    f _ _ _ = return "/dev/null"
+    result = checkWithIncludesAndSourcePath [("foo/lib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\n# shellcheck source=lib\nsource kittens",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Checks/Custom.hs

@@ -0,0 +1,21 @@
+{-
+    This empty file is provided for ease of patching in site specific checks.
+    However, there are no guarantees regarding compatibility between versions.
+-} 
+
+{-# LANGUAGE TemplateHaskell #-}
+module ShellCheck.Checks.Custom (checker, ShellCheck.Checks.Custom.runTests) where
+
+import ShellCheck.AnalyzerLib
+import Test.QuickCheck
+
+checker :: Parameters -> Checker
+checker params = Checker {
+    perScript = const $ return (),
+    perToken = const $ return ()
+  }
+
+prop_CustomTestsWork = True
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Checks/ShellSupport.hs

@@ -0,0 +1,545 @@
+{-
+    Copyright 2012-2016 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE FlexibleContexts #-}
+module ShellCheck.Checks.ShellSupport (checker , ShellCheck.Checks.ShellSupport.runTests) where
+
+import ShellCheck.AST
+import ShellCheck.ASTLib
+import ShellCheck.AnalyzerLib
+import ShellCheck.Interface
+import ShellCheck.Regex
+
+import Control.Monad
+import Control.Monad.RWS
+import Data.Char
+import Data.List
+import Data.Maybe
+import qualified Data.Map as Map
+import qualified Data.Set as Set
+import Test.QuickCheck.All (forAllProperties)
+import Test.QuickCheck.Test (quickCheckWithResult, stdArgs, maxSuccess)
+
+data ForShell = ForShell [Shell] (Token -> Analysis)
+
+getChecker params list = Checker {
+        perScript = nullCheck,
+        perToken = foldl composeAnalyzers nullCheck $ mapMaybe include list
+    }
+  where
+    shell = shellType params
+    include (ForShell list a) = do
+        guard $ shell `elem` list
+        return a
+
+checker params = getChecker params checks
+
+checks = [
+    checkForDecimals
+    ,checkBashisms
+    ,checkEchoSed
+    ,checkBraceExpansionVars
+    ,checkMultiDimensionalArrays
+    ,checkPS1Assignments
+    ]
+
+testChecker (ForShell _ t) =
+    Checker {
+        perScript = nullCheck,
+        perToken = t
+    }
+verify c s = producesComments (testChecker c) s == Just True
+verifyNot c s = producesComments (testChecker c) s == Just False
+
+prop_checkForDecimals1 = verify checkForDecimals "((3.14*c))"
+prop_checkForDecimals2 = verify checkForDecimals "foo[1.2]=bar"
+prop_checkForDecimals3 = verifyNot checkForDecimals "declare -A foo; foo[1.2]=bar"
+checkForDecimals = ForShell [Sh, Dash, Bash] f
+  where
+    f t@(TA_Expansion id _) = potentially $ do
+        str <- getLiteralString t
+        first <- str !!! 0
+        guard $ isDigit first && '.' `elem` str
+        return $ err id 2079 "(( )) doesn't support decimals. Use bc or awk."
+    f _ = return ()
+
+
+prop_checkBashisms = verify checkBashisms "while read a; do :; done < <(a)"
+prop_checkBashisms2 = verify checkBashisms "[ foo -nt bar ]"
+prop_checkBashisms3 = verify checkBashisms "echo $((i++))"
+prop_checkBashisms4 = verify checkBashisms "rm !(*.hs)"
+prop_checkBashisms5 = verify checkBashisms "source file"
+prop_checkBashisms6 = verify checkBashisms "[ \"$a\" == 42 ]"
+prop_checkBashisms7 = verify checkBashisms "echo ${var[1]}"
+prop_checkBashisms8 = verify checkBashisms "echo ${!var[@]}"
+prop_checkBashisms9 = verify checkBashisms "echo ${!var*}"
+prop_checkBashisms10= verify checkBashisms "echo ${var:4:12}"
+prop_checkBashisms11= verifyNot checkBashisms "echo ${var:-4}"
+prop_checkBashisms12= verify checkBashisms "echo ${var//foo/bar}"
+prop_checkBashisms13= verify checkBashisms "exec -c env"
+prop_checkBashisms14= verify checkBashisms "echo -n \"Foo: \""
+prop_checkBashisms15= verify checkBashisms "let n++"
+prop_checkBashisms16= verify checkBashisms "echo $RANDOM"
+prop_checkBashisms17= verify checkBashisms "echo $((RANDOM%6+1))"
+prop_checkBashisms18= verify checkBashisms "foo &> /dev/null"
+prop_checkBashisms19= verify checkBashisms "foo > file*.txt"
+prop_checkBashisms20= verify checkBashisms "read -ra foo"
+prop_checkBashisms21= verify checkBashisms "[ -a foo ]"
+prop_checkBashisms22= verifyNot checkBashisms "[ foo -a bar ]"
+prop_checkBashisms23= verify checkBashisms "trap mything ERR INT"
+prop_checkBashisms24= verifyNot checkBashisms "trap mything INT TERM"
+prop_checkBashisms25= verify checkBashisms "cat < /dev/tcp/host/123"
+prop_checkBashisms26= verify checkBashisms "trap mything ERR SIGTERM"
+prop_checkBashisms27= verify checkBashisms "echo *[^0-9]*"
+prop_checkBashisms28= verify checkBashisms "exec {n}>&2"
+prop_checkBashisms29= verify checkBashisms "echo ${!var}"
+prop_checkBashisms30= verify checkBashisms "printf -v '%s' \"$1\""
+prop_checkBashisms31= verify checkBashisms "printf '%q' \"$1\""
+prop_checkBashisms32= verifyNot checkBashisms "#!/bin/dash\n[ foo -nt bar ]"
+prop_checkBashisms33= verify checkBashisms "#!/bin/sh\necho -n foo"
+prop_checkBashisms34= verifyNot checkBashisms "#!/bin/dash\necho -n foo"
+prop_checkBashisms35= verifyNot checkBashisms "#!/bin/dash\nlocal foo"
+prop_checkBashisms36= verifyNot checkBashisms "#!/bin/dash\nread -p foo -r bar"
+prop_checkBashisms37= verifyNot checkBashisms "HOSTNAME=foo; echo $HOSTNAME"
+prop_checkBashisms38= verify checkBashisms "RANDOM=9; echo $RANDOM"
+prop_checkBashisms39= verify checkBashisms "foo-bar() { true; }"
+prop_checkBashisms40= verify checkBashisms "echo $(<file)"
+prop_checkBashisms41= verify checkBashisms "echo `<file`"
+prop_checkBashisms42= verify checkBashisms "trap foo int"
+prop_checkBashisms43= verify checkBashisms "trap foo sigint"
+prop_checkBashisms44= verifyNot checkBashisms "#!/bin/dash\ntrap foo int"
+prop_checkBashisms45= verifyNot checkBashisms "#!/bin/dash\ntrap foo INT"
+prop_checkBashisms46= verify checkBashisms "#!/bin/dash\ntrap foo SIGINT"
+prop_checkBashisms47= verify checkBashisms "#!/bin/dash\necho foo 42>/dev/null"
+prop_checkBashisms48= verifyNot checkBashisms "#!/bin/sh\necho $LINENO"
+prop_checkBashisms49= verify checkBashisms "#!/bin/dash\necho $MACHTYPE"
+prop_checkBashisms50= verify checkBashisms "#!/bin/sh\ncmd >& file"
+prop_checkBashisms51= verifyNot checkBashisms "#!/bin/sh\ncmd 2>&1"
+prop_checkBashisms52= verifyNot checkBashisms "#!/bin/sh\ncmd >&2"
+prop_checkBashisms53= verifyNot checkBashisms "#!/bin/sh\nprintf -- -f\n"
+prop_checkBashisms54= verify checkBashisms "#!/bin/sh\nfoo+=bar"
+prop_checkBashisms55= verify checkBashisms "#!/bin/sh\necho ${@%foo}"
+prop_checkBashisms56= verifyNot checkBashisms "#!/bin/sh\necho ${##}"
+prop_checkBashisms57= verifyNot checkBashisms "#!/bin/dash\nulimit -c 0"
+prop_checkBashisms58= verify checkBashisms "#!/bin/sh\nulimit -c 0"
+prop_checkBashisms59 = verify checkBashisms "#!/bin/sh\njobs -s"
+prop_checkBashisms60 = verifyNot checkBashisms "#!/bin/sh\njobs -p"
+prop_checkBashisms61 = verifyNot checkBashisms "#!/bin/sh\njobs -lp"
+prop_checkBashisms62 = verify checkBashisms "#!/bin/sh\nexport -f foo"
+prop_checkBashisms63 = verifyNot checkBashisms "#!/bin/sh\nexport -p"
+prop_checkBashisms64 = verify checkBashisms "#!/bin/sh\nreadonly -a"
+prop_checkBashisms65 = verifyNot checkBashisms "#!/bin/sh\nreadonly -p"
+prop_checkBashisms66 = verifyNot checkBashisms "#!/bin/sh\ncd -P ."
+prop_checkBashisms67 = verify checkBashisms "#!/bin/sh\ncd -P -e ."
+prop_checkBashisms68 = verify checkBashisms "#!/bin/sh\numask -p"
+prop_checkBashisms69 = verifyNot checkBashisms "#!/bin/sh\numask -S"
+prop_checkBashisms70 = verify checkBashisms "#!/bin/sh\ntrap -l"
+prop_checkBashisms71 = verify checkBashisms "#!/bin/sh\ntype -a ls"
+prop_checkBashisms72 = verifyNot checkBashisms "#!/bin/sh\ntype ls"
+prop_checkBashisms73 = verify checkBashisms "#!/bin/sh\nunset -n namevar"
+prop_checkBashisms74 = verifyNot checkBashisms "#!/bin/sh\nunset -f namevar"
+prop_checkBashisms75 = verifyNot checkBashisms "#!/bin/sh\necho \"-n foo\""
+prop_checkBashisms76 = verifyNot checkBashisms "#!/bin/sh\necho \"-ne foo\""
+prop_checkBashisms77 = verifyNot checkBashisms "#!/bin/sh\necho -Q foo"
+prop_checkBashisms78 = verify checkBashisms "#!/bin/sh\necho -ne foo"
+prop_checkBashisms79 = verify checkBashisms "#!/bin/sh\nhash -l"
+prop_checkBashisms80 = verifyNot checkBashisms "#!/bin/sh\nhash -r"
+prop_checkBashisms81 = verifyNot checkBashisms "#!/bin/dash\nhash -v"
+prop_checkBashisms82 = verifyNot checkBashisms "#!/bin/sh\nset -v +o allexport -o errexit -C"
+prop_checkBashisms83 = verifyNot checkBashisms "#!/bin/sh\nset --"
+prop_checkBashisms84 = verify checkBashisms "#!/bin/sh\nset -o pipefail"
+prop_checkBashisms85 = verify checkBashisms "#!/bin/sh\nset -B"
+prop_checkBashisms86 = verifyNot checkBashisms "#!/bin/dash\nset -o emacs"
+prop_checkBashisms87 = verify checkBashisms "#!/bin/sh\nset -o emacs"
+prop_checkBashisms88 = verifyNot checkBashisms "#!/bin/sh\nset -- wget -o foo 'https://some.url'"
+prop_checkBashisms89 = verifyNot checkBashisms "#!/bin/sh\nopts=$-\nset -\"$opts\""
+prop_checkBashisms90 = verifyNot checkBashisms "#!/bin/sh\nset -o \"$opt\""
+prop_checkBashisms91 = verify checkBashisms "#!/bin/sh\nwait -n"
+prop_checkBashisms92 = verify checkBashisms "#!/bin/sh\necho $((16#FF))"
+prop_checkBashisms93 = verify checkBashisms "#!/bin/sh\necho $(( 10#$(date +%m) ))"
+prop_checkBashisms94 = verify checkBashisms "#!/bin/sh\n[ -v var ]"
+prop_checkBashisms95 = verify checkBashisms "#!/bin/sh\necho $_"
+prop_checkBashisms96 = verifyNot checkBashisms "#!/bin/dash\necho $_"
+checkBashisms = ForShell [Sh, Dash] $ \t -> do
+    params <- ask
+    kludge params t
+ where
+  -- This code was copy-pasted from Analytics where params was a variable
+  kludge params = bashism
+   where
+    isDash = shellType params == Dash
+    warnMsg id s =
+        if isDash
+        then warn id 2169 $ "In dash, " ++ s ++ " not supported."
+        else warn id 2039 $ "In POSIX sh, " ++ s ++ " undefined."
+
+    bashism (T_ProcSub id _ _) = warnMsg id "process substitution is"
+    bashism (T_Extglob id _ _) = warnMsg id "extglob is"
+    bashism (T_DollarSingleQuoted id _) = warnMsg id "$'..' is"
+    bashism (T_DollarDoubleQuoted id _) = warnMsg id "$\"..\" is"
+    bashism (T_ForArithmetic id _ _ _ _) = warnMsg id "arithmetic for loops are"
+    bashism (T_Arithmetic id _) = warnMsg id "standalone ((..)) is"
+    bashism (T_DollarBracket id _) = warnMsg id "$[..] in place of $((..)) is"
+    bashism (T_SelectIn id _ _ _) = warnMsg id "select loops are"
+    bashism (T_BraceExpansion id _) = warnMsg id "brace expansion is"
+    bashism (T_Condition id DoubleBracket _) = warnMsg id "[[ ]] is"
+    bashism (T_HereString id _) = warnMsg id "here-strings are"
+    bashism (TC_Binary id SingleBracket op _ _)
+        | op `elem` [ "<", ">", "\\<", "\\>", "<=", ">=", "\\<=", "\\>="] =
+            unless isDash $ warnMsg id $ "lexicographical " ++ op ++ " is"
+    bashism (TC_Binary id SingleBracket op _ _)
+        | op `elem` [ "-nt", "-ef" ] =
+            unless isDash $ warnMsg id $ op ++ " is"
+    bashism (TC_Binary id SingleBracket "==" _ _) =
+            warnMsg id "== in place of = is"
+    bashism (TC_Binary id SingleBracket "=~" _ _) =
+            warnMsg id "=~ regex matching is"
+    bashism (TC_Unary id SingleBracket "-v" _) =
+            warnMsg id "unary -v (in place of [ -n \"${var+x}\" ]) is"
+    bashism (TC_Unary id _ "-a" _) =
+            warnMsg id "unary -a in place of -e is"
+    bashism (TA_Unary id op _)
+        | op `elem` [ "|++", "|--", "++|", "--|"] =
+            warnMsg id $ filter (/= '|') op ++ " is"
+    bashism (TA_Binary id "**" _ _) = warnMsg id "exponentials are"
+    bashism (T_FdRedirect id "&" (T_IoFile _ (T_Greater _) _)) = warnMsg id "&> is"
+    bashism (T_FdRedirect id "" (T_IoFile _ (T_GREATAND _) _)) = warnMsg id ">& is"
+    bashism (T_FdRedirect id ('{':_) _) = warnMsg id "named file descriptors are"
+    bashism (T_FdRedirect id num _)
+        | all isDigit num && length num > 1 = warnMsg id "FDs outside 0-9 are"
+    bashism (T_Assignment id Append _ _ _) =
+        warnMsg id "+= is"
+    bashism (T_IoFile id _ word) | isNetworked =
+            warnMsg id "/dev/{tcp,udp} is"
+        where
+            file = onlyLiteralString word
+            isNetworked = any (`isPrefixOf` file) ["/dev/tcp", "/dev/udp"]
+    bashism (T_Glob id str) | "[^" `isInfixOf` str =
+            warnMsg id "^ in place of ! in glob bracket expressions is"
+
+    bashism t@(TA_Variable id str _) | isBashVariable str =
+        warnMsg id $ str ++ " is"
+
+    bashism t@(T_DollarBraced id _ token) = do
+        mapM_ check expansion
+        when (isBashVariable var) $
+                    warnMsg id $ var ++ " is"
+      where
+        str = bracedString t
+        var = getBracedReference str
+        check (regex, feature) =
+            when (isJust $ matchRegex regex str) $ warnMsg id feature
+
+    bashism t@(T_Pipe id "|&") =
+        warnMsg id "|& in place of 2>&1 | is"
+    bashism (T_Array id _) =
+        warnMsg id "arrays are"
+    bashism (T_IoFile id _ t) | isGlob t =
+        warnMsg id "redirecting to/from globs is"
+    bashism (T_CoProc id _ _) =
+        warnMsg id "coproc is"
+
+    bashism (T_Function id _ _ str _) | not (isVariableName str) =
+        warnMsg id "naming functions outside [a-zA-Z_][a-zA-Z0-9_]* is"
+
+    bashism (T_DollarExpansion id [x]) | isOnlyRedirection x =
+        warnMsg id "$(<file) to read files is"
+    bashism (T_Backticked id [x]) | isOnlyRedirection x =
+        warnMsg id "`<file` to read files is"
+
+    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
+        | t `isCommand` "echo" && argString `matches` flagRegex =
+            if isDash
+            then
+                when (argString /= "-n") $
+                    warnMsg (getId arg) "echo flags besides -n"
+            else
+                warnMsg (getId arg) "echo flags are"
+      where
+          argString = concat $ oversimplify arg
+          flagRegex = mkRegex "^-[eEsn]+$"
+
+    bashism t@(T_SimpleCommand _ _ (cmd:arg:_))
+        | t `isCommand` "exec" && "-" `isPrefixOf` concat (oversimplify arg) =
+            warnMsg (getId arg) "exec flags are"
+    bashism t@(T_SimpleCommand id _ _)
+        | t `isCommand` "let" = warnMsg id "'let' is"
+    bashism t@(T_SimpleCommand _ _ (cmd:args))
+        | t `isCommand` "set" = unless isDash $
+            checkOptions $ getLiteralArgs args
+      where
+        -- Get the literal options from a list of arguments,
+        -- up until the first non-literal one
+        getLiteralArgs :: [Token] -> [(Id, String)]
+        getLiteralArgs (first:rest) = fromMaybe [] $ do
+            str <- getLiteralString first
+            return $ (getId first, str) : getLiteralArgs rest
+        getLiteralArgs [] = []
+
+        -- Check a flag-option pair (such as -o errexit)
+        checkOptions (flag@(fid,flag') : opt@(oid,opt') : rest)
+            | flag' `matches` oFlagRegex = do
+                when (opt' `notElem` longOptions) $
+                  warnMsg oid $ "set option " <> opt' <> " is"
+                checkFlags (flag:rest)
+            | otherwise = checkFlags (flag:opt:rest)
+        checkOptions (flag:rest) = checkFlags (flag:rest)
+        checkOptions _           = return ()
+
+        -- Check that each option in a sequence of flags
+        -- (such as -aveo) is valid
+        checkFlags (flag@(fid, flag'):rest)
+            | startsOption flag' = do
+                unless (flag' `matches` validFlagsRegex) $
+                  forM_ (tail flag') $ \letter ->
+                    when (letter `notElem` optionsSet) $
+                      warnMsg fid $ "set flag " <> ('-':letter:" is")
+                checkOptions rest
+            | beginsWithDoubleDash flag' = do
+                warnMsg fid $ "set flag " <> flag' <> " is"
+                checkOptions rest
+            -- Either a word that doesn't start with a dash, or simply '--',
+            -- so stop checking.
+            | otherwise = return ()
+        checkFlags [] = return ()
+
+        options              = "abCefhmnuvxo"
+        optionsSet           = Set.fromList options
+        startsOption         = (`matches` mkRegex "^(\\+|-[^-])")
+        oFlagRegex           = mkRegex $ "^[-+][" <> options <> "]*o$"
+        validFlagsRegex      = mkRegex $ "^[-+]([" <> options <> "]+o?|o)$"
+        beginsWithDoubleDash = (`matches` mkRegex "^--.+$")
+        longOptions          = Set.fromList
+            [ "allexport", "errexit", "ignoreeof", "monitor", "noclobber"
+            , "noexec", "noglob", "nolog", "notify" , "nounset", "verbose"
+            , "vi", "xtrace" ]
+
+    bashism t@(T_SimpleCommand id _ (cmd:rest)) =
+        let name = fromMaybe "" $ getCommandName t
+            flags = getLeadingFlags t
+        in do
+            when (name `elem` unsupportedCommands) $
+                warnMsg id $ "'" ++ name ++ "' is"
+            potentially $ do
+                allowed' <- Map.lookup name allowedFlags
+                allowed <- allowed'
+                (word, flag) <- listToMaybe $
+                    filter (\x -> (not . null . snd $ x) && snd x `notElem` allowed) flags
+                return . warnMsg (getId word) $ name ++ " -" ++ flag ++ " is"
+
+            when (name == "source") $ warnMsg id "'source' in place of '.' is"
+            when (name == "trap") $
+                let
+                    check token = potentially $ do
+                        str <- getLiteralString token
+                        let upper = map toUpper str
+                        return $ do
+                            when (upper `elem` ["ERR", "DEBUG", "RETURN"]) $
+                                warnMsg (getId token) $ "trapping " ++ str ++ " is"
+                            when ("SIG" `isPrefixOf` upper) $
+                                warnMsg (getId token)
+                                    "prefixing signal names with 'SIG' is"
+                            when (not isDash && upper /= str) $
+                                warnMsg (getId token)
+                                    "using lower/mixed case for signal names is"
+                in
+                    mapM_ check (drop 1 rest)
+
+            when (name == "printf") $ potentially $ do
+                format <- rest !!! 0  -- flags are covered by allowedFlags
+                let literal = onlyLiteralString format
+                guard $ "%q" `isInfixOf` literal
+                return $ warnMsg (getId format) "printf %q is"
+      where
+        unsupportedCommands = [
+            "let", "caller", "builtin", "complete", "compgen", "declare", "dirs", "disown",
+            "enable", "mapfile", "readarray", "pushd", "popd", "shopt", "suspend",
+            "typeset"
+            ] ++ if not isDash then ["local"] else []
+        allowedFlags = Map.fromList [
+            ("cd", Just ["L", "P"]),
+            ("exec", Just []),
+            ("export", Just ["p"]),
+            ("hash", Just $ if isDash then ["r", "v"] else ["r"]),
+            ("jobs", Just ["l", "p"]),
+            ("printf", Just []),
+            ("read", Just $ if isDash then ["r", "p"] else ["r"]),
+            ("readonly", Just ["p"]),
+            ("trap", Just []),
+            ("type", Just []),
+            ("ulimit", if isDash then Nothing else Just ["f"]),
+            ("umask", Just ["S"]),
+            ("unset", Just ["f", "v"]),
+            ("wait", Just [])
+            ]
+    bashism t@(T_SourceCommand id src _) =
+        let name = fromMaybe "" $ getCommandName src
+        in when (name == "source") $ warnMsg id "'source' in place of '.' is"
+    bashism (TA_Expansion _ (T_Literal id str : _)) | str `matches` radix =
+        when (str `matches` radix) $ warnMsg id "arithmetic base conversion is"
+      where
+        radix = mkRegex "^[0-9]+#"
+    bashism _ = return ()
+
+    varChars="_0-9a-zA-Z"
+    expansion = let re = mkRegex in [
+        (re $ "^![" ++ varChars ++ "]", "indirect expansion is"),
+        (re $ "^[" ++ varChars ++ "]+\\[.*\\]$", "array references are"),
+        (re $ "^![" ++ varChars ++ "]+\\[[*@]]$", "array key expansion is"),
+        (re $ "^![" ++ varChars ++ "]+[*@]$", "name matching prefixes are"),
+        (re $ "^[" ++ varChars ++ "*@]+:[^-=?+]", "string indexing is"),
+        (re $ "^([*@][%#]|#[@*])", "string operations on $@/$* are"),
+        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?/", "string replacement is")
+        ]
+    bashVars = [
+        "OSTYPE", "MACHTYPE", "HOSTTYPE", "HOSTNAME",
+        "DIRSTACK", "EUID", "UID", "SHLVL", "PIPESTATUS", "SHELLOPTS",
+        "_"
+        ]
+    bashDynamicVars = [ "RANDOM", "SECONDS" ]
+    dashVars = [ "_" ]
+    isBashVariable var =
+        (var `elem` bashDynamicVars
+            || var `elem` bashVars && not (isAssigned var))
+        && not (isDash && var `elem` dashVars)
+    isAssigned var = any f (variableFlow params)
+      where
+        f x = case x of
+                Assignment (_, _, name, _) -> name == var
+                _ -> False
+
+prop_checkEchoSed1 = verify checkEchoSed "FOO=$(echo \"$cow\" | sed 's/foo/bar/g')"
+prop_checkEchoSed1b= verify checkEchoSed "FOO=$(sed 's/foo/bar/g' <<< \"$cow\")"
+prop_checkEchoSed2 = verify checkEchoSed "rm $(echo $cow | sed -e 's,foo,bar,')"
+prop_checkEchoSed2b= verify checkEchoSed "rm $(sed -e 's,foo,bar,' <<< $cow)"
+checkEchoSed = ForShell [Bash, Ksh] f
+  where
+    f (T_Redirecting id lefts r) =
+        when (any redirectHereString lefts) $
+            checkSed id rcmd
+      where
+        redirectHereString :: Token -> Bool
+        redirectHereString t = case t of
+            (T_FdRedirect _ _ T_HereString{}) -> True
+            _                                 -> False
+        rcmd = oversimplify r
+
+    f (T_Pipeline id _ [a, b]) =
+        when (acmd == ["echo", "${VAR}"]) $
+            checkSed id bcmd
+      where
+        acmd = oversimplify a
+        bcmd = oversimplify b
+
+    f _ = return ()
+
+    checkSed id ["sed", v]       = checkIn id v
+    checkSed id ["sed", "-e", v] = checkIn id v
+    checkSed _ _                 = return ()
+
+    -- This should have used backreferences, but TDFA doesn't support them
+    sedRe = mkRegex "^s(.)([^\n]*)g?$"
+    isSimpleSed s = fromMaybe False $ do
+        [first,rest] <- matchRegex sedRe s
+        let delimiters = filter (== head first) rest
+        guard $ length delimiters == 2
+        return True
+    checkIn id s =
+        when (isSimpleSed s) $
+            style id 2001 "See if you can use ${variable//search/replace} instead."
+
+
+prop_checkBraceExpansionVars1 = verify checkBraceExpansionVars "echo {1..$n}"
+prop_checkBraceExpansionVars2 = verifyNot checkBraceExpansionVars "echo {1,3,$n}"
+prop_checkBraceExpansionVars3 = verify checkBraceExpansionVars "eval echo DSC{0001..$n}.jpg"
+prop_checkBraceExpansionVars4 = verify checkBraceExpansionVars "echo {$i..100}"
+checkBraceExpansionVars = ForShell [Bash] f
+  where
+    f t@(T_BraceExpansion id list) = mapM_ check list
+      where
+        check element =
+            when (any (`isInfixOf` toString element) ["$..", "..$"]) $ do
+                c <- isEvaled element
+                if c
+                    then style id 2175 "Quote this invalid brace expansion since it should be passed literally to eval."
+                    else warn id 2051 "Bash doesn't support variables in brace range expansions."
+    f _ = return ()
+
+    literalExt t =
+        case t of
+            T_DollarBraced {} -> return "$"
+            T_DollarExpansion {} -> return "$"
+            T_DollarArithmetic {} -> return "$"
+            otherwise -> return "-"
+    toString t = fromJust $ getLiteralStringExt literalExt t
+    isEvaled t = do
+        cmd <- getClosestCommandM t
+        return $ isJust cmd && fromJust cmd `isUnqualifiedCommand` "eval"
+
+
+prop_checkMultiDimensionalArrays1 = verify checkMultiDimensionalArrays "foo[a][b]=3"
+prop_checkMultiDimensionalArrays2 = verifyNot checkMultiDimensionalArrays "foo[a]=3"
+prop_checkMultiDimensionalArrays3 = verify checkMultiDimensionalArrays "foo=( [a][b]=c )"
+prop_checkMultiDimensionalArrays4 = verifyNot checkMultiDimensionalArrays "foo=( [a]=c )"
+prop_checkMultiDimensionalArrays5 = verify checkMultiDimensionalArrays "echo ${foo[bar][baz]}"
+prop_checkMultiDimensionalArrays6 = verifyNot checkMultiDimensionalArrays "echo ${foo[bar]}"
+checkMultiDimensionalArrays = ForShell [Bash] f
+  where
+    f token =
+        case token of
+            T_Assignment _ _ name (first:second:_) _ -> about second
+            T_IndexedElement _ (first:second:_) _ -> about second
+            T_DollarBraced {} ->
+                when (isMultiDim token) $ about token
+            _ -> return ()
+    about t = warn (getId t) 2180 "Bash does not support multidimensional arrays. Use 1D or associative arrays."
+
+    re = mkRegex "^\\[.*\\]\\[.*\\]"  -- Fixme, this matches ${foo:- [][]} and such as well
+    isMultiDim t = getBracedModifier (bracedString t) `matches` re
+
+prop_checkPS11 = verify checkPS1Assignments "PS1='\\033[1;35m\\$ '"
+prop_checkPS11a= verify checkPS1Assignments "export PS1='\\033[1;35m\\$ '"
+prop_checkPSf2 = verify checkPS1Assignments "PS1='\\h \\e[0m\\$ '"
+prop_checkPS13 = verify checkPS1Assignments "PS1=$'\\x1b[c '"
+prop_checkPS14 = verify checkPS1Assignments "PS1=$'\\e[3m; '"
+prop_checkPS14a= verify checkPS1Assignments "export PS1=$'\\e[3m; '"
+prop_checkPS15 = verifyNot checkPS1Assignments "PS1='\\[\\033[1;35m\\]\\$ '"
+prop_checkPS16 = verifyNot checkPS1Assignments "PS1='\\[\\e1m\\e[1m\\]\\$ '"
+prop_checkPS17 = verifyNot checkPS1Assignments "PS1='e033x1B'"
+prop_checkPS18 = verifyNot checkPS1Assignments "PS1='\\[\\e\\]'"
+checkPS1Assignments = ForShell [Bash] f
+  where
+    f token = case token of
+        (T_Assignment _ _ "PS1" _ word) -> warnFor word
+        _ -> return ()
+
+    warnFor word =
+        let contents = concat $ oversimplify word in
+            when (containsUnescaped contents) $
+                info (getId word) 2025 "Make sure all escape sequences are enclosed in \\[..\\] to prevent line wrapping issues"
+    containsUnescaped s =
+        let unenclosed = subRegex enclosedRegex s "" in
+           isJust $ matchRegex escapeRegex unenclosed
+    enclosedRegex = mkRegex "\\\\\\[.*\\\\\\]" -- FIXME: shouldn't be eager
+    escapeRegex = mkRegex "\\\\x1[Bb]|\\\\e|\x1B|\\\\033"
+
+
+return []
+runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Data.hs

@@ -1,5 +1,6 @@
 module ShellCheck.Data where
 
+import ShellCheck.Interface
 import Data.Version (showVersion)
 import Paths_ShellCheck (version)
 
@@ -24,20 +25,46 @@ internalVariables = [
     "FUNCNEST", "GLOBIGNORE", "HISTCONTROL", "HISTFILE", "HISTFILESIZE",
     "HISTIGNORE", "HISTSIZE", "HISTTIMEFORMAT", "HOME", "HOSTFILE", "IFS",
     "IGNOREEOF", "INPUTRC", "LANG", "LC_ALL", "LC_COLLATE", "LC_CTYPE",
-    "LC_MESSAGES", "LC_NUMERIC", "LINES", "MAIL", "MAILCHECK", "MAILPATH",
-    "OPTERR", "PATH", "POSIXLY_CORRECT", "PROMPT_COMMAND",
-    "PROMPT_DIRTRIM", "PS1", "PS2", "PS3", "PS4", "SHELL", "TIMEFORMAT",
-    "TMOUT", "TMPDIR", "auto_resume", "histchars", "COPROC",
+    "LC_MESSAGES", "LC_MONETARY", "LC_NUMERIC", "LC_TIME", "LINES", "MAIL",
+    "MAILCHECK", "MAILPATH", "OPTERR", "PATH", "POSIXLY_CORRECT",
+    "PROMPT_COMMAND", "PROMPT_DIRTRIM", "PS1", "PS2", "PS3", "PS4", "SHELL",
+    "TIMEFORMAT", "TMOUT", "TMPDIR", "auto_resume", "histchars", "COPROC",
 
     -- Other
-    "USER", "TZ", "TERM"
+    "USER", "TZ", "TERM", "LOGNAME", "LD_LIBRARY_PATH", "LANGUAGE", "DISPLAY",
+    "HOSTNAME", "KRB5CCNAME", "XAUTHORITY"
+
+    -- Ksh
+    , ".sh.version"
+
+    -- shflags
+    , "FLAGS_ARGC", "FLAGS_ARGV", "FLAGS_ERROR", "FLAGS_FALSE", "FLAGS_HELP",
+    "FLAGS_PARENT", "FLAGS_RESERVED", "FLAGS_TRUE", "FLAGS_VERSION",
+    "flags_error", "flags_return"
   ]
 
-variablesWithoutSpaces = [
-    "$", "-", "?", "!",
+specialVariablesWithoutSpaces = [
+    "$", "-", "?", "!", "#"
+  ]
+variablesWithoutSpaces = specialVariablesWithoutSpaces ++ [
     "BASHPID", "BASH_ARGC", "BASH_LINENO", "BASH_SUBSHELL", "EUID", "LINENO",
     "OPTIND", "PPID", "RANDOM", "SECONDS", "SHELLOPTS", "SHLVL", "UID",
     "COLUMNS", "HISTFILESIZE", "HISTSIZE", "LINES"
+
+    -- shflags
+    , "FLAGS_ERROR", "FLAGS_FALSE", "FLAGS_TRUE"
+  ]
+
+specialVariables = specialVariablesWithoutSpaces ++ ["@", "*"]
+
+unbracedVariables = specialVariables ++ [
+    "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"
+  ]
+
+arrayVariables = [
+    "BASH_ALIASES", "BASH_ARGC", "BASH_ARGV", "BASH_CMDS", "BASH_LINENO",
+    "BASH_REMATCH", "BASH_SOURCE", "BASH_VERSINFO", "COMP_WORDS", "COPROC",
+    "DIRSTACK", "FUNCNAME", "GROUPS", "MAPFILE", "PIPESTATUS", "COMPREPLY"
   ]
 
 commonCommands = [
@@ -66,6 +93,14 @@ commonCommands = [
     "zcat"
   ]
 
+nonReadingCommands = [
+    "alias", "basename", "bg", "cal", "cd", "chgrp", "chmod", "chown",
+    "cp", "du", "echo", "export", "false", "fg", "fuser", "getconf",
+    "getopt", "getopts", "ipcrm", "ipcs", "jobs", "kill", "ln", "ls",
+    "locale", "mv", "printf", "ps", "pwd", "renice", "rm", "rmdir",
+    "set", "sleep", "touch", "trap", "true", "ulimit", "unalias", "uname"
+    ]
+
 sampleWords = [
     "alpha", "bravo", "charlie", "delta", "echo", "foxtrot",
     "golf", "hotel", "india", "juliett", "kilo", "lima", "mike",
@@ -73,3 +108,27 @@ sampleWords = [
     "tango", "uniform", "victor", "whiskey", "xray", "yankee",
     "zulu"
   ]
+
+binaryTestOps = [
+    "-nt", "-ot", "-ef", "==", "!=", "<=", ">=", "-eq", "-ne", "-lt", "-le",
+    "-gt", "-ge", "=~", ">", "<", "=", "\\<", "\\>", "\\<=", "\\>="
+  ]
+
+unaryTestOps = [
+    "!", "-a", "-b", "-c", "-d", "-e", "-f", "-g", "-h", "-L", "-k", "-p",
+    "-r", "-s", "-S", "-t", "-u", "-w", "-x", "-O", "-G", "-N", "-z", "-n",
+    "-o", "-v", "-R"
+  ]
+
+shellForExecutable :: String -> Maybe Shell
+shellForExecutable name =
+    case name of
+        "sh"    -> return Sh
+        "bash"  -> return Bash
+        "bats"  -> return Bash
+        "dash"  -> return Dash
+        "ash"   -> return Dash -- There's also a warning for this.
+        "ksh"   -> return Ksh
+        "ksh88" -> return Ksh
+        "ksh93" -> return Ksh
+        otherwise -> Nothing

src/ShellCheck/Fixer.hs

@@ -0,0 +1,409 @@
+{-
+    Copyright 2018-2019 Vidar Holen, Ng Zhi An
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+
+{-# LANGUAGE TemplateHaskell #-}
+module ShellCheck.Fixer (applyFix, removeTabStops, mapPositions, Ranged(..), runTests) where
+
+import ShellCheck.Interface
+import Control.Monad.State
+import Data.Array
+import Data.List
+import Data.Semigroup
+import GHC.Exts (sortWith)
+import Test.QuickCheck
+
+-- The Ranged class is used for types that has a start and end position.
+class Ranged a where
+    start   :: a -> Position
+    end     :: a -> Position
+    overlap :: a -> a -> Bool
+    overlap x y =
+        (yStart >= xStart && yStart < xEnd) || (yStart < xStart && yEnd > xStart)
+        where
+            yStart = start y
+            yEnd = end y
+            xStart = start x
+            xEnd = end x
+    -- Set a new start and end position on a Ranged
+    setRange :: (Position, Position) -> a -> a
+
+-- Tests auto-verify that overlap commutes
+assertOverlap x y = overlap x y && overlap y x
+assertNoOverlap x y = not (overlap x y) && not (overlap y x)
+
+prop_overlap_contiguous = assertNoOverlap
+        (tFromStart 10 12 "foo" 1)
+        (tFromStart 12 14 "bar" 2)
+
+prop_overlap_adjacent_zerowidth = assertNoOverlap
+        (tFromStart 3 3 "foo" 1)
+        (tFromStart 3 3 "bar" 2)
+
+prop_overlap_enclosed = assertOverlap
+        (tFromStart 3 5 "foo" 1)
+        (tFromStart 1 10 "bar" 2)
+
+prop_overlap_partial = assertOverlap
+        (tFromStart 1 5 "foo" 1)
+        (tFromStart 3 7 "bar" 2)
+
+
+instance Ranged PositionedComment where
+    start = pcStartPos
+    end = pcEndPos
+    setRange (s, e) pc = pc {
+        pcStartPos = s,
+        pcEndPos = e
+    }
+
+instance Ranged Replacement where
+    start = repStartPos
+    end   = repEndPos
+    setRange (s, e) r = r {
+        repStartPos = s,
+        repEndPos = e
+    }
+
+-- The Monoid instance for Fix merges fixes that do not conflict.
+-- TODO: Make an efficient 'mconcat'
+instance Monoid Fix where
+    mempty = newFix
+    mappend = (<>)
+
+instance Semigroup Fix where
+    f1 <> f2 =
+        -- FIXME: This might need to also discard adjacent zero-width ranges for
+        --        when two fixes change the same AST node, e.g. `foo` -> "$(foo)"
+        if or [ r2 `overlap` r1 | r1 <- fixReplacements f1, r2 <- fixReplacements f2 ]
+        then f1
+        else newFix {
+            fixReplacements = fixReplacements f1 ++ fixReplacements f2
+            }
+
+-- Conveniently apply a transformation to positions in a Fix
+mapPositions :: (Position -> Position) -> Fix -> Fix
+mapPositions f = adjustFix
+  where
+    adjustReplacement rep =
+        rep {
+            repStartPos = f $ repStartPos rep,
+            repEndPos = f $ repEndPos rep
+        }
+    adjustFix fix =
+        fix {
+            fixReplacements = map adjustReplacement $ fixReplacements fix
+        }
+
+-- Rewrite a Ranged from a tabstop of 8 to 1
+removeTabStops :: Ranged a => a -> Array Int String -> a
+removeTabStops range ls =
+    let startColumn = realignColumn lineNo colNo range
+        endColumn = realignColumn endLineNo endColNo range
+        startPosition = (start range) { posColumn = startColumn }
+        endPosition = (end range) { posColumn = endColumn } in
+    setRange (startPosition, endPosition) range
+  where
+    realignColumn lineNo colNo c =
+      if lineNo c > 0 && lineNo c <= fromIntegral (length ls)
+      then real (ls ! fromIntegral (lineNo c)) 0 0 (colNo c)
+      else colNo c
+    real _ r v target | target <= v = r
+    -- hit this case at the end of line, and if we don't hit the target
+    -- return real + (target - v)
+    real [] r v target = r + (target - v)
+    real ('\t':rest) r v target = real rest (r+1) (v + 8 - (v `mod` 8)) target
+    real (_:rest) r v target = real rest (r+1) (v+1) target
+    lineNo = posLine . start
+    endLineNo = posLine . end
+    colNo = posColumn . start
+    endColNo = posColumn . end
+
+
+-- A replacement that spans multiple line is applied by:
+-- 1. merging the affected lines into a single string using `unlines`
+-- 2. apply the replacement as if it only spanned a single line
+-- The tricky part is adjusting the end column of the replacement
+-- (the end line doesn't matter because there is only one line)
+--
+--   aaS  <--- start of replacement (row 1 column 3)
+--   bbbb
+--   cEc
+--    \------- end of replacement (row 3 column 2)
+--
+-- a flattened string will look like:
+--
+--   "aaS\nbbbb\ncEc\n"
+--
+-- The column of E has to be adjusted by:
+-- 1. lengths of lines to be replaced, except the end row itself
+-- 2. end column of the replacement
+-- 3. number of '\n' by `unlines`
+multiToSingleLine :: [Fix] -> Array Int String -> ([Fix], String)
+multiToSingleLine fixes lines =
+    (map (mapPositions adjust) fixes, unlines $ elems lines)
+  where
+    -- A prefix sum tree from line number to column shift.
+    -- FIXME: The tree will be totally unbalanced.
+    shiftTree :: PSTree Int
+    shiftTree =
+        foldl (\t (n,s) -> addPSValue (n+1) (length s + 1) t) newPSTree $
+            assocs lines
+    singleString = unlines $ elems lines
+    adjust pos =
+        pos {
+            posLine = 1,
+            posColumn = (posColumn pos) +
+                (fromIntegral $ getPrefixSum (fromIntegral $ posLine pos) shiftTree)
+        }
+
+-- Apply a fix and return resulting lines.
+-- The number of lines can increase or decrease with no obvious mapping back, so
+-- the function does not return an array.
+applyFix :: Fix -> Array Int String -> [String]
+applyFix fix fileLines =
+    let
+        untabbed = fix {
+            fixReplacements =
+                map (\c -> removeTabStops c fileLines) $
+                    fixReplacements fix
+            }
+        (adjustedFixes, singleLine) = multiToSingleLine [untabbed] fileLines
+    in
+        lines . runFixer $ applyFixes2 adjustedFixes singleLine
+
+
+-- start and end comes from pos, which is 1 based
+prop_doReplace1 = doReplace 0 0 "1234" "A" == "A1234" -- technically not valid
+prop_doReplace2 = doReplace 1 1 "1234" "A" == "A1234"
+prop_doReplace3 = doReplace 1 2 "1234" "A" == "A234"
+prop_doReplace4 = doReplace 3 3 "1234" "A" == "12A34"
+prop_doReplace5 = doReplace 4 4 "1234" "A" == "123A4"
+prop_doReplace6 = doReplace 5 5 "1234" "A" == "1234A"
+doReplace start end o r =
+    let si = fromIntegral (start-1)
+        ei = fromIntegral (end-1)
+        (x, xs) = splitAt si o
+        (y, z) = splitAt (ei - si) xs
+    in
+    x ++ r ++ z
+
+-- Fail if the 'expected' string is not result when applying 'fixes' to 'original'.
+testFixes :: String -> String -> [Fix] -> Bool
+testFixes expected original fixes =
+    actual == expected
+  where
+    actual = runFixer (applyFixes2 fixes original)
+
+
+-- A Fixer allows doing repeated modifications of a string where each
+-- replacement automatically accounts for shifts from previous ones.
+type Fixer a =  State (PSTree Int) a
+
+-- Apply a single replacement using its indices into the original string.
+-- It does not handle multiple lines, all line indices must be 1.
+applyReplacement2 :: Replacement -> String -> Fixer String
+applyReplacement2 rep string = do
+    tree <- get
+    let transform pos = pos + getPrefixSum pos tree
+    let originalPos = (repStartPos rep, repEndPos rep)
+        (oldStart, oldEnd) = tmap (fromInteger . posColumn) originalPos
+        (newStart, newEnd) = tmap transform (oldStart, oldEnd)
+
+    let (l1, l2) = tmap posLine originalPos in
+        when (l1 /= 1 || l2 /= 1) $
+            error "ShellCheck internal error, please report: bad cross-line fix"
+
+    let replacer = repString rep
+    let shift = (length replacer) - (oldEnd - oldStart)
+    let insertionPoint =
+          case repInsertionPoint rep of
+              InsertBefore -> oldStart
+              InsertAfter  -> oldEnd+1
+    put $ addPSValue insertionPoint shift tree
+
+    return $ doReplace newStart newEnd string replacer
+  where
+    tmap f (a,b) = (f a, f b)
+
+-- Apply a list of Replacements in the correct order
+applyReplacements2 :: [Replacement] -> String -> Fixer String
+applyReplacements2 reps str =
+    foldM (flip applyReplacement2) str $
+        reverse $ sortWith repPrecedence reps
+
+-- Apply all fixes with replacements in the correct order
+applyFixes2 :: [Fix] -> String -> Fixer String
+applyFixes2 fixes = applyReplacements2 (concatMap fixReplacements fixes)
+
+-- Get the final value of a Fixer.
+runFixer :: Fixer a -> a
+runFixer f = evalState f newPSTree
+
+
+
+-- A Prefix Sum Tree that lets you look up the sum of values at and below an index.
+-- It's implemented essentially as a Fenwick tree without the bit-based balancing.
+-- The last Num is the sum of the left branch plus current element.
+data PSTree n = PSBranch n (PSTree n) (PSTree n) n | PSLeaf
+    deriving (Show)
+
+newPSTree :: Num n => PSTree n
+newPSTree = PSLeaf
+
+-- Get the sum of values whose keys are <= 'target'
+getPrefixSum :: (Ord n, Num n) => n -> PSTree n -> n
+getPrefixSum = f 0
+  where
+    f sum _ PSLeaf = sum
+    f sum target (PSBranch pivot left right cumulative) =
+        case () of
+            _ | target < pivot -> f sum target left
+            _ | target > pivot -> f (sum+cumulative) target right
+            _ -> sum+cumulative
+
+-- Add a value to the Prefix Sum tree at the given index.
+-- Values accumulate: addPSValue 42 2 . addPSValue 42 3 == addPSValue 42 5
+addPSValue :: (Ord n, Num n) => n -> n -> PSTree n -> PSTree n
+addPSValue key value tree = if value == 0 then tree else f tree
+  where
+    f PSLeaf = PSBranch key PSLeaf PSLeaf value
+    f (PSBranch pivot left right sum) =
+        case () of
+            _ | key < pivot -> PSBranch pivot (f left) right (sum + value)
+            _ | key > pivot -> PSBranch pivot left (f right) sum
+            _ -> PSBranch pivot left right (sum + value)
+
+prop_pstreeSumsCorrectly kvs targets =
+  let
+    -- Trivial O(n * m) implementation
+    dumbPrefixSums :: [(Int, Int)] -> [Int] -> [Int]
+    dumbPrefixSums kvs targets =
+        let prefixSum target = sum . map snd . filter (\(k,v) -> k <= target) $ kvs
+        in map prefixSum targets
+    -- PSTree O(n * log m) implementation
+    smartPrefixSums :: [(Int, Int)] -> [Int] -> [Int]
+    smartPrefixSums kvs targets =
+        let tree = foldl (\tree (pos, shift) -> addPSValue pos shift tree) PSLeaf kvs
+        in map (\x -> getPrefixSum x tree) targets
+  in smartPrefixSums kvs targets == dumbPrefixSums kvs targets
+
+
+-- Semi-convenient functions for constructing tests.
+testFix :: [Replacement] -> Fix
+testFix list = newFix {
+        fixReplacements = list
+    }
+
+tFromStart :: Int -> Int -> String -> Int -> Replacement
+tFromStart start end repl order =
+    newReplacement {
+        repStartPos = newPosition {
+            posLine = 1,
+            posColumn = fromIntegral start
+        },
+        repEndPos = newPosition {
+            posLine = 1,
+            posColumn = fromIntegral end
+        },
+        repString = repl,
+        repPrecedence = order,
+        repInsertionPoint = InsertAfter
+    }
+
+tFromEnd start end repl order =
+    (tFromStart start end repl order) {
+        repInsertionPoint = InsertBefore
+    }
+
+prop_simpleFix1 = testFixes "hello world" "hell world" [
+    testFix [
+        tFromEnd 5 5 "o" 1
+    ]]
+
+prop_anchorsLeft = testFixes "-->foobar<--" "--><--" [
+    testFix [
+        tFromStart 4 4 "foo" 1,
+        tFromStart 4 4 "bar" 2
+    ]]
+
+prop_anchorsRight = testFixes "-->foobar<--" "--><--" [
+    testFix [
+        tFromEnd 4 4 "bar" 1,
+        tFromEnd 4 4 "foo" 2
+    ]]
+
+prop_anchorsBoth1 = testFixes "-->foobar<--" "--><--" [
+    testFix [
+        tFromStart 4 4 "bar" 2,
+        tFromEnd 4 4 "foo" 1
+    ]]
+
+prop_anchorsBoth2 = testFixes "-->foobar<--" "--><--" [
+    testFix [
+        tFromEnd 4 4 "foo" 2,
+        tFromStart 4 4 "bar" 1
+    ]]
+
+prop_composeFixes1 = testFixes "cd \"$1\" || exit" "cd $1" [
+    testFix [
+        tFromStart 4 4 "\"" 10,
+        tFromEnd   6 6 "\"" 10
+    ],
+    testFix [
+        tFromEnd 6 6 " || exit" 5
+    ]]
+
+prop_composeFixes2 = testFixes "$(\"$1\")" "`$1`" [
+    testFix [
+        tFromStart 1 2 "$(" 5,
+        tFromEnd   4 5 ")" 5
+    ],
+    testFix [
+        tFromStart 2 2 "\"" 10,
+        tFromEnd 4 4 "\"" 10
+    ]]
+
+prop_composeFixes3 = testFixes "(x)[x]" "xx" [
+    testFix [
+        tFromStart 1 1 "(" 4,
+        tFromEnd   2 2 ")" 3,
+        tFromStart 2 2 "[" 2,
+        tFromEnd   3 3 "]" 1
+    ]]
+
+prop_composeFixes4 = testFixes "(x)[x]" "xx" [
+    testFix [
+        tFromStart 1 1 "(" 4,
+        tFromStart 2 2 "[" 3,
+        tFromEnd   2 2 ")" 2,
+        tFromEnd   3 3 "]" 1
+    ]]
+
+prop_composeFixes5 = testFixes "\"$(x)\"" "`x`" [
+    testFix [
+        tFromStart 1 2 "$(" 2,
+        tFromEnd   3 4 ")"  2,
+        tFromStart 1 1 "\"" 1,
+        tFromEnd   4 4 "\"" 1
+    ]]
+
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Formatter/CheckStyle.hs

@@ -0,0 +1,95 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.CheckStyle (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Char
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = do
+        putStrLn "<?xml version='1.0' encoding='UTF-8'?>"
+        putStrLn "<checkstyle version='4.3'>",
+
+    onFailure = outputError,
+    onResult = outputResults,
+
+    footer = putStrLn "</checkstyle>"
+}
+
+outputResults cr sys =
+    if null comments
+    then outputFile (crFilename cr) "" []
+    else mapM_ outputGroup fileGroups
+  where
+    comments = crComments cr
+    fileGroups = groupWith sourceFile comments
+    outputGroup group = do
+        let filename = sourceFile (head group)
+        result <- (siReadFile sys) filename
+        let contents = either (const "") id result
+        outputFile filename contents group
+
+outputFile filename contents warnings = do
+    let comments = makeNonVirtual warnings contents
+    putStrLn . formatFile filename $ comments
+
+formatFile name comments = concat [
+    "<file ", attr "name" name, ">\n",
+        concatMap formatComment comments,
+    "</file>"
+    ]
+
+formatComment c = concat [
+    "<error ",
+    attr "line" $ show . lineNo $ c,
+    attr "column" $ show . colNo $ c,
+    attr "severity" . severity $ severityText c,
+    attr "message" $ messageText c,
+    attr "source" $ "ShellCheck.SC" ++ show (codeNo c),
+    "/>\n"
+    ]
+
+outputError file error = putStrLn $ concat [
+    "<file ", attr "name" file, ">\n",
+    "<error ",
+        attr "line" "1",
+        attr "column" "1",
+        attr "severity" "error",
+        attr "message" error,
+        attr "source" "ShellCheck",
+    "/>\n",
+    "</file>"
+    ]
+
+
+attr s v = concat [ s, "='", escape v, "' " ]
+escape = concatMap escape'
+escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
+isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
+
+severity "error" = "error"
+severity "warning" = "warning"
+severity _ = "info"

src/ShellCheck/Formatter/Diff.hs

@@ -0,0 +1,255 @@
+{-
+    Copyright 2019 Vidar 'koala_man' Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE TemplateHaskell #-}
+module ShellCheck.Formatter.Diff (format, ShellCheck.Formatter.Diff.runTests) where
+
+import ShellCheck.Interface
+import ShellCheck.Fixer
+import ShellCheck.Formatter.Format
+
+import Control.Monad
+import Data.Algorithm.Diff
+import Data.Array
+import Data.IORef
+import Data.List
+import qualified Data.Monoid as Monoid
+import Data.Maybe
+import qualified Data.Map as M
+import GHC.Exts (sortWith)
+import System.IO
+import System.FilePath
+
+import Test.QuickCheck
+
+import Debug.Trace
+ltt x = trace (show x) x
+
+format :: FormatterOptions -> IO Formatter
+format options = do
+    didOutput <- newIORef False
+    shouldColor <- shouldOutputColor (foColorOption options)
+    let color = if shouldColor then colorize else nocolor
+    return Formatter {
+        header = return (),
+        footer = checkFooter didOutput color,
+        onFailure = reportFailure color,
+        onResult  = reportResult didOutput color
+    }
+
+
+contextSize = 3
+red = 31
+green = 32
+yellow = 33
+cyan = 36
+bold = 1
+
+nocolor n = id
+colorize n s = (ansi n) ++ s ++ (ansi 0)
+ansi n = "\x1B[" ++ show n ++ "m"
+
+printErr :: ColorFunc -> String -> IO ()
+printErr color = hPutStrLn stderr . color bold . color red
+reportFailure color file msg = printErr color $ file ++ ": " ++ msg
+
+checkFooter didOutput color = do
+    output <- readIORef didOutput
+    unless output $
+            printErr color "Issues were detected, but none were auto-fixable. Use another format to see them."
+
+type ColorFunc = (Int -> String -> String)
+data LFStatus = LinefeedMissing | LinefeedOk
+data DiffDoc a = DiffDoc String LFStatus [DiffRegion a]
+data DiffRegion a = DiffRegion (Int, Int) (Int, Int) [Diff a]
+
+reportResult :: (IORef Bool) -> ColorFunc -> CheckResult -> SystemInterface IO -> IO ()
+reportResult didOutput color result sys = do
+    let comments = crComments result
+    let suggestedFixes = mapMaybe pcFix comments
+    let fixmap = buildFixMap suggestedFixes
+    mapM_ output $ M.toList fixmap
+  where
+    output (name, fix) = do
+        file <- (siReadFile sys) name
+        case file of
+            Right contents -> do
+                putStrLn $ formatDoc color $ makeDiff name contents fix
+                writeIORef didOutput True
+            Left msg -> reportFailure color name msg
+
+hasTrailingLinefeed str =
+    case str of
+        [] -> True
+        _ -> last str == '\n'
+
+coversLastLine regions =
+    case regions of
+        [] -> False
+        _ -> (fst $ last regions)
+
+-- TODO: Factor this out into a unified diff library because we're doing a lot
+-- of the heavy lifting anyways.
+makeDiff :: String -> String -> Fix -> DiffDoc String
+makeDiff name contents fix = do
+    let hunks = groupDiff $ computeDiff contents fix
+    let lf = if coversLastLine hunks && not (hasTrailingLinefeed contents)
+             then LinefeedMissing
+             else LinefeedOk
+    DiffDoc name lf $ findRegions hunks
+
+computeDiff :: String -> Fix -> [Diff String]
+computeDiff contents fix =
+    let old = lines contents
+        array = listArray (1, fromIntegral $ (length old)) old
+        new = applyFix fix array
+    in getDiff old new
+
+-- Group changes into hunks
+groupDiff :: [Diff a] -> [(Bool, [Diff a])]
+groupDiff = filter (\(_, l) -> not (null l)) . hunt []
+  where
+    -- Churn through 'Both's until we find a difference
+    hunt current [] = [(False, reverse current)]
+    hunt current (x@Both {}:rest) = hunt (x:current) rest
+    hunt current list =
+        let (context, previous) = splitAt contextSize current
+        in (False, reverse previous) : gather context 0 list
+
+    -- Pick out differences until we find a run of Both's
+    gather current n [] =
+        let (extras, patch) = splitAt (max 0 $ n - contextSize) current
+        in [(True, reverse patch), (False, reverse extras)]
+
+    gather current n list@(Both {}:_) | n == contextSize*2 =
+        let (context, previous) = splitAt contextSize current
+        in (True, reverse previous) : hunt context list
+
+    gather current n (x@Both {}:rest) = gather (x:current) (n+1) rest
+    gather current n (x:rest) = gather (x:current) 0 rest
+
+-- Get line numbers for hunks
+findRegions :: [(Bool, [Diff String])] -> [DiffRegion String]
+findRegions = find' 1 1
+  where
+    find' _ _ [] = []
+    find' left right ((output, run):rest) =
+        let (dl, dr) = countDelta run
+            remainder = find' (left+dl) (right+dr) rest
+        in
+            if output
+            then DiffRegion (left, dl) (right, dr) run : remainder
+            else remainder
+
+-- Get left/right line counts for a hunk
+countDelta :: [Diff a] -> (Int, Int)
+countDelta = count' 0 0
+  where
+    count' left right [] = (left, right)
+    count' left right (x:rest) =
+        case x of
+            Both {} -> count' (left+1) (right+1) rest
+            First {} -> count' (left+1) right rest
+            Second {} -> count' left (right+1) rest
+
+formatRegion :: ColorFunc -> LFStatus -> DiffRegion String -> String
+formatRegion color lf (DiffRegion left right diffs) =
+    let header = color cyan ("@@ -" ++ (tup left) ++ " +" ++ (tup right) ++" @@")
+    in
+        unlines $ header : reverse (getStrings lf (reverse diffs))
+  where
+    noLF = "\\ No newline at end of file"
+
+    getStrings LinefeedOk list = map format list
+    getStrings LinefeedMissing list@((Both _ _):_) = noLF : map format list
+    getStrings LinefeedMissing list@((First _):_) = noLF : map format list
+    getStrings LinefeedMissing (last:rest) = format last : getStrings LinefeedMissing rest
+
+    tup (a,b) = (show a) ++ "," ++ (show b)
+    format (Both x _) = ' ':x
+    format (First x) = color red $ '-':x
+    format (Second x) = color green $ '+':x
+
+splitLast [] = ([], [])
+splitLast x =
+    let (last, rest) = splitAt 1 $ reverse x
+    in (reverse rest, last)
+
+formatDoc color (DiffDoc name lf regions) =
+    let (most, last) = splitLast regions
+    in
+          (color bold $ "--- " ++ ("a" </> name)) ++ "\n" ++
+          (color bold $ "+++ " ++ ("b" </> name)) ++ "\n" ++
+          concatMap (formatRegion color LinefeedOk) most ++
+          concatMap (formatRegion color lf) last
+
+-- Create a Map from filename to Fix
+buildFixMap :: [Fix] -> M.Map String Fix
+buildFixMap fixes = perFile
+  where
+    splitFixes = concatMap splitFixByFile fixes
+    perFile = groupByMap (posFile . repStartPos . head . fixReplacements) splitFixes
+
+-- There are currently no multi-file fixes, but let's handle it anyways
+splitFixByFile :: Fix -> [Fix]
+splitFixByFile fix = map makeFix $ groupBy sameFile (fixReplacements fix)
+  where
+    sameFile rep1 rep2 = (posFile $ repStartPos rep1) == (posFile $ repStartPos rep2)
+    makeFix reps = newFix { fixReplacements = reps }
+
+groupByMap :: (Ord k, Monoid v) => (v -> k) -> [v] -> M.Map k v
+groupByMap f = M.fromListWith Monoid.mappend . map (\x -> (f x, x))
+
+-- For building unit tests
+b n = Both n n
+l = First
+r = Second
+
+prop_identifiesProperContext = groupDiff [b 1, b 2, b 3, b 4, l 5, b 6, b 7, b 8, b 9] ==
+    [(False, [b 1]), -- Omitted
+    (True, [b 2, b 3, b 4, l 5, b 6, b 7, b 8]), -- A change with three lines of context
+    (False, [b 9])]  -- Omitted
+
+prop_includesContextFromStartIfNecessary = groupDiff [b 4, l 5, b 6, b 7, b 8, b 9] ==
+    [ -- Nothing omitted
+    (True, [b 4, l 5, b 6, b 7, b 8]), -- A change with three lines of context
+    (False, [b 9])]  -- Omitted
+
+prop_includesContextUntilEndIfNecessary = groupDiff [b 4, l 5] ==
+    [ -- Nothing omitted
+        (True, [b 4, l 5])
+    ] -- Nothing Omitted
+
+prop_splitsIntoMultipleHunks = groupDiff [l 1, b 1, b 2, b 3, b 4, b 5, b 6, b 7, r 8] ==
+    [ -- Nothing omitted
+        (True, [l 1, b 1, b 2, b 3]),
+        (False, [b 4]),
+        (True, [b 5, b 6, b 7, r 8])
+    ] -- Nothing Omitted
+
+prop_splitsIntoMultipleHunksUnlessTouching = groupDiff [l 1, b 1, b 2, b 3, b 4, b 5, b 6, r 7] ==
+    [
+        (True, [l 1, b 1, b 2, b 3, b 4, b 5, b 6, r 7])
+    ]
+
+prop_countDeltasWorks = countDelta [b 1, l 2, r 3, r 4, b 5] == (3,4)
+prop_countDeltasWorks2 = countDelta [] == (0,0)
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Formatter/Format.hs

@@ -0,0 +1,79 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.Format where
+
+import ShellCheck.Data
+import ShellCheck.Interface
+import ShellCheck.Fixer
+
+import Control.Monad
+import Data.Array
+import Data.List
+import System.IO
+import System.Info
+
+-- A formatter that carries along an arbitrary piece of data
+data Formatter = Formatter {
+    header ::  IO (),
+    onResult :: CheckResult -> SystemInterface IO -> IO (),
+    onFailure :: FilePath -> ErrorMessage -> IO (),
+    footer :: IO ()
+}
+
+sourceFile = posFile . pcStartPos
+lineNo = posLine . pcStartPos
+endLineNo = posLine . pcEndPos
+colNo  = posColumn . pcStartPos
+endColNo = posColumn . pcEndPos
+codeNo = cCode . pcComment
+messageText = cMessage . pcComment
+
+severityText :: PositionedComment -> String
+severityText pc =
+    case cSeverity (pcComment pc) of
+        ErrorC   -> "error"
+        WarningC -> "warning"
+        InfoC    -> "info"
+        StyleC   -> "style"
+
+-- Realign comments from a tabstop of 8 to 1
+makeNonVirtual comments contents =
+    map fix comments
+  where
+    list = lines contents
+    arr = listArray (1, length list) list
+    untabbedFix f = newFix {
+      fixReplacements = map (\r -> removeTabStops r arr) (fixReplacements f)
+    }
+    fix c = (removeTabStops c arr) {
+      pcFix = fmap untabbedFix (pcFix c)
+    }
+
+
+shouldOutputColor :: ColorOption -> IO Bool
+shouldOutputColor colorOption = do
+    term <- hIsTerminalDevice stdout
+    let windows = "mingw" `isPrefixOf` os
+    let isUsableTty = term && not windows
+    let useColor = case colorOption of
+                       ColorAlways -> True
+                       ColorNever -> False
+                       ColorAuto -> isUsableTty
+    return useColor

src/ShellCheck/Formatter/GCC.hs

@@ -0,0 +1,65 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.GCC (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = return (),
+    footer = return (),
+    onFailure = outputError,
+    onResult = outputAll
+}
+
+outputError file error = hPutStrLn stderr $ file ++ ": " ++ error
+
+outputAll cr sys = mapM_ f groups
+  where
+    comments = crComments cr
+    groups = groupWith sourceFile comments
+    f :: [PositionedComment] -> IO ()
+    f group = do
+        let filename = sourceFile (head group)
+        result <- (siReadFile sys) filename
+        let contents = either (const "") id result
+        outputResult filename contents group
+
+outputResult filename contents warnings = do
+    let comments = makeNonVirtual warnings contents
+    mapM_ (putStrLn . formatComment filename) comments
+
+formatComment filename c = concat [
+    filename, ":",
+    show $ lineNo c, ":",
+    show $ colNo c, ": ",
+    case severityText c of
+        "error" -> "error"
+        "warning" -> "warning"
+        _ -> "note",
+    ": ",
+    concat . lines $ messageText c,
+    " [SC", show $ codeNo c, "]"
+  ]

src/ShellCheck/Formatter/JSON.hs

@@ -0,0 +1,110 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.JSON (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Aeson
+import Data.IORef
+import Data.Monoid
+import GHC.Exts
+import System.IO
+import qualified Data.ByteString.Lazy.Char8 as BL
+
+format :: IO Formatter
+format = do
+    ref <- newIORef []
+    return Formatter {
+        header = return (),
+        onResult = collectResult ref,
+        onFailure = outputError,
+        footer = finish ref
+    }
+
+instance ToJSON Replacement where
+    toJSON replacement =
+        let start = repStartPos replacement
+            end = repEndPos replacement
+            str = repString replacement in
+        object [
+          "precedence" .= repPrecedence replacement,
+          "insertionPoint"  .=
+            case repInsertionPoint replacement of
+                InsertBefore -> "beforeStart" :: String
+                InsertAfter  -> "afterEnd",
+          "line" .= posLine start,
+          "column" .= posColumn start,
+          "endLine" .= posLine end,
+          "endColumn" .= posColumn end,
+          "replacement" .= str
+        ]
+
+instance ToJSON PositionedComment where
+  toJSON comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    object [
+      "file" .= posFile start,
+      "line" .= posLine start,
+      "endLine" .= posLine end,
+      "column" .= posColumn start,
+      "endColumn" .= posColumn end,
+      "level" .= severityText comment,
+      "code" .= cCode c,
+      "message" .= cMessage c,
+      "fix" .= pcFix comment
+    ]
+
+  toEncoding comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    pairs (
+         "file" .= posFile start
+      <> "line" .= posLine start
+      <> "endLine" .= posLine end
+      <> "column" .= posColumn start
+      <> "endColumn" .= posColumn end
+      <> "level" .= severityText comment
+      <> "code" .= cCode c
+      <> "message" .= cMessage c
+      <> "fix" .= pcFix comment
+    )
+
+instance ToJSON Fix where
+    toJSON fix = object [
+        "replacements" .= fixReplacements fix
+        ]
+
+outputError file msg = hPutStrLn stderr $ file ++ ": " ++ msg
+
+collectResult ref cr sys = mapM_ f groups
+  where
+    comments = crComments cr
+    groups = groupWith sourceFile comments
+    f :: [PositionedComment] -> IO ()
+    f group = modifyIORef ref (\x -> comments ++ x)
+
+finish ref = do
+    list <- readIORef ref
+    BL.putStrLn $ encode list

src/ShellCheck/Formatter/JSON1.hs

@@ -0,0 +1,127 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.JSON1 (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Aeson
+import Data.IORef
+import Data.Monoid
+import GHC.Exts
+import System.IO
+import qualified Data.ByteString.Lazy.Char8 as BL
+
+format :: IO Formatter
+format = do
+    ref <- newIORef []
+    return Formatter {
+        header = return (),
+        onResult = collectResult ref,
+        onFailure = outputError,
+        footer = finish ref
+    }
+
+data Json1Output = Json1Output {
+    comments :: [PositionedComment]
+    }
+
+instance ToJSON Json1Output where
+    toJSON result = object [
+        "comments" .= comments result
+        ]
+    toEncoding result = pairs (
+        "comments" .= comments result
+        )
+
+instance ToJSON Replacement where
+    toJSON replacement =
+        let start = repStartPos replacement
+            end = repEndPos replacement
+            str = repString replacement in
+        object [
+          "precedence" .= repPrecedence replacement,
+          "insertionPoint"  .=
+            case repInsertionPoint replacement of
+                InsertBefore -> "beforeStart" :: String
+                InsertAfter  -> "afterEnd",
+          "line" .= posLine start,
+          "column" .= posColumn start,
+          "endLine" .= posLine end,
+          "endColumn" .= posColumn end,
+          "replacement" .= str
+        ]
+
+instance ToJSON PositionedComment where
+  toJSON comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    object [
+      "file" .= posFile start,
+      "line" .= posLine start,
+      "endLine" .= posLine end,
+      "column" .= posColumn start,
+      "endColumn" .= posColumn end,
+      "level" .= severityText comment,
+      "code" .= cCode c,
+      "message" .= cMessage c,
+      "fix" .= pcFix comment
+    ]
+
+  toEncoding comment =
+    let start = pcStartPos comment
+        end = pcEndPos comment
+        c = pcComment comment in
+    pairs (
+         "file" .= posFile start
+      <> "line" .= posLine start
+      <> "endLine" .= posLine end
+      <> "column" .= posColumn start
+      <> "endColumn" .= posColumn end
+      <> "level" .= severityText comment
+      <> "code" .= cCode c
+      <> "message" .= cMessage c
+      <> "fix" .= pcFix comment
+    )
+
+instance ToJSON Fix where
+    toJSON fix = object [
+        "replacements" .= fixReplacements fix
+        ]
+
+outputError file msg = hPutStrLn stderr $ file ++ ": " ++ msg
+
+collectResult ref cr sys = mapM_ f groups
+  where
+    comments = crComments cr
+    groups = groupWith sourceFile comments
+    f :: [PositionedComment] -> IO ()
+    f group = do
+        let filename = sourceFile (head group)
+        result <- siReadFile sys filename
+        let contents = either (const "") id result
+        let comments' = makeNonVirtual comments contents
+        modifyIORef ref (\x -> comments' ++ x)
+
+finish ref = do
+    list <- readIORef ref
+    BL.putStrLn $ encode $ Json1Output { comments = list }

src/ShellCheck/Formatter/Quiet.hs

@@ -0,0 +1,36 @@
+{-
+    Copyright 2019 Austin Voecks
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.Quiet (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Control.Monad
+import Data.IORef
+import System.Exit
+
+format :: FormatterOptions -> IO Formatter
+format options =
+    return Formatter {
+        header = return (),
+        footer = return (),
+        onFailure = \ _ _ -> exitFailure,
+        onResult  = \ result _ -> unless (null $ crComments result) exitFailure
+    }

src/ShellCheck/Formatter/TTY.hs

@@ -0,0 +1,197 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.TTY (format) where
+
+import ShellCheck.Fixer
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Control.Monad
+import Data.Array
+import Data.Foldable
+import Data.Ord
+import Data.IORef
+import Data.List
+import Data.Maybe
+import GHC.Exts
+import System.IO
+import System.Info
+
+wikiLink = "https://www.shellcheck.net/wiki/"
+
+-- An arbitrary Ord thing to order warnings
+type Ranking = (Char, Severity, Integer)
+-- Ansi coloring function
+type ColorFunc = (String -> String -> String)
+
+format :: FormatterOptions -> IO Formatter
+format options = do
+    topErrorRef <- newIORef []
+    return Formatter {
+        header = return (),
+        footer = outputWiki topErrorRef,
+        onFailure = outputError options,
+        onResult = outputResult options topErrorRef
+    }
+
+colorForLevel level =
+    case level of
+        "error"   -> 31 -- red
+        "warning" -> 33 -- yellow
+        "info"    -> 32 -- green
+        "style"   -> 32 -- green
+        "verbose" -> 32 -- green
+        "message" -> 1 -- bold
+        "source"  -> 0 -- none
+        _ -> 0         -- none
+
+rankError :: PositionedComment -> Ranking
+rankError err = (ranking, cSeverity $ pcComment err, cCode $ pcComment err)
+  where
+    ranking =
+        if cCode (pcComment err) `elem` uninteresting
+        then 'Z'
+        else 'A'
+
+    -- A list of the most generic, least directly helpful
+    -- error codes to downrank.
+    uninteresting = [
+        1009, -- Mentioned parser error was..
+        1019, -- Expected this to be an argument
+        1036, -- ( is invalid here
+        1047, -- Expected 'fi'
+        1062, -- Expected 'done'
+        1070, -- Parsing stopped here (generic)
+        1072, -- Missing/unexpected ..
+        1073, -- Couldn't parse this ..
+        1088, -- Parsing stopped here (paren)
+        1089  -- Parsing stopped here (keyword)
+        ]
+
+appendComments errRef comments max = do
+    previous <- readIORef errRef
+    let current = map (\x -> (rankError x, cCode $ pcComment x, cMessage $ pcComment x)) comments
+    writeIORef errRef . take max . nubBy equal . sort $ previous ++ current
+  where
+    fst3 (x,_,_) = x
+    equal x y = fst3 x == fst3 y
+
+outputWiki :: IORef [(Ranking, Integer, String)] -> IO ()
+outputWiki errRef = do
+    issues <- readIORef errRef
+    unless (null issues) $ do
+        putStrLn "For more information:"
+        mapM_ showErr issues
+  where
+    showErr (_, code, msg) =
+        putStrLn $ "  " ++ wikiLink ++ "SC" ++ show code ++ " -- " ++ shorten msg
+    limit = 36
+    shorten msg =
+        if length msg < limit
+        then msg
+        else (take (limit-3) msg) ++ "..."
+
+outputError options file error = do
+    color <- getColorFunc $ foColorOption options
+    hPutStrLn stderr $ color "error" $ file ++ ": " ++ error
+
+outputResult options ref result sys = do
+    color <- getColorFunc $ foColorOption options
+    let comments = crComments result
+    appendComments ref comments (fromIntegral $ foWikiLinkCount options)
+    let fileGroups = groupWith sourceFile comments
+    mapM_ (outputForFile color sys) fileGroups
+
+outputForFile color sys comments = do
+    let fileName = sourceFile (head comments)
+    result <- (siReadFile sys) fileName
+    let contents = either (const "") id result
+    let fileLinesList = lines contents
+    let lineCount = length fileLinesList
+    let fileLines = listArray (1, lineCount) fileLinesList
+    let groups = groupWith lineNo comments
+    mapM_ (\commentsForLine -> do
+        let lineNum = fromIntegral $ lineNo (head commentsForLine)
+        let line = if lineNum < 1 || lineNum > lineCount
+                        then ""
+                        else fileLines ! fromIntegral lineNum
+        putStrLn ""
+        putStrLn $ color "message" $
+           "In " ++ fileName ++" line " ++ show lineNum ++ ":"
+        putStrLn (color "source" line)
+        mapM_ (\c -> putStrLn (color (severityText c) $ cuteIndent c)) commentsForLine
+        putStrLn ""
+        showFixedString color commentsForLine (fromIntegral lineNum) fileLines
+      ) groups
+
+-- Pick out only the lines necessary to show a fix in action
+sliceFile :: Fix -> Array Int String -> (Fix, Array Int String)
+sliceFile fix lines =
+    (mapPositions adjust fix, sliceLines lines)
+  where
+    (minLine, maxLine) =
+        foldl (\(mm, mx) pos -> ((min mm $ fromIntegral $ posLine pos), (max mx $ fromIntegral $ posLine pos)))
+                (maxBound, minBound) $
+            concatMap (\x -> [repStartPos x, repEndPos x]) $ fixReplacements fix
+    sliceLines :: Array Int String -> Array Int String
+    sliceLines = ixmap (1, maxLine - minLine + 1) (\x -> x + minLine - 1)
+    adjust pos =
+        pos {
+            posLine = posLine pos - (fromIntegral minLine) + 1
+        }
+
+showFixedString :: ColorFunc -> [PositionedComment] -> Int -> Array Int String -> IO ()
+showFixedString color comments lineNum fileLines =
+    let line = fileLines ! fromIntegral lineNum in
+    case mapMaybe pcFix comments of
+        [] -> return ()
+        fixes -> do
+            -- Folding automatically removes overlap
+            let mergedFix = fold fixes
+            -- We show the complete, associated fixes, whether or not it includes this
+            -- and/or other unrelated lines.
+            let (excerptFix, excerpt) = sliceFile mergedFix fileLines
+            -- in the spirit of error prone
+            putStrLn $ color "message" "Did you mean: "
+            putStrLn $ unlines $ applyFix excerptFix excerpt
+
+cuteIndent :: PositionedComment -> String
+cuteIndent comment =
+    replicate (fromIntegral $ colNo comment - 1) ' ' ++
+        makeArrow ++ " " ++ code (codeNo comment) ++ ": " ++ messageText comment
+  where
+    arrow n = '^' : replicate (fromIntegral $ n-2) '-' ++ "^"
+    makeArrow =
+        let sameLine = lineNo comment == endLineNo comment
+            delta = endColNo comment - colNo comment
+        in
+            if sameLine && delta > 2 && delta < 32 then arrow delta else "^--"
+
+code num = "SC" ++ show num
+
+getColorFunc :: ColorOption -> IO ColorFunc
+getColorFunc colorOption = do
+    useColor <- shouldOutputColor colorOption
+    return $ if useColor then colorComment else const id
+  where
+    colorComment level comment =
+        ansi (colorForLevel level) ++ comment ++ clear
+    clear = ansi 0
+    ansi n = "\x1B[" ++ show n ++ "m"

src/ShellCheck/Interface.hs

@@ -0,0 +1,328 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE DeriveGeneric, DeriveAnyClass #-}
+module ShellCheck.Interface
+    (
+    SystemInterface(..)
+    , CheckSpec(csFilename, csScript, csCheckSourced, csIncludedWarnings, csExcludedWarnings, csShellTypeOverride, csMinSeverity, csIgnoreRC, csOptionalChecks)
+    , CheckResult(crFilename, crComments)
+    , ParseSpec(psFilename, psScript, psCheckSourced, psIgnoreRC, psShellTypeOverride)
+    , ParseResult(prComments, prTokenPositions, prRoot)
+    , AnalysisSpec(asScript, asShellType, asFallbackShell, asExecutionMode, asCheckSourced, asTokenPositions, asOptionalChecks)
+    , AnalysisResult(arComments)
+    , FormatterOptions(foColorOption, foWikiLinkCount)
+    , Shell(Ksh, Sh, Bash, Dash)
+    , ExecutionMode(Executed, Sourced)
+    , ErrorMessage
+    , Code
+    , Severity(ErrorC, WarningC, InfoC, StyleC)
+    , Position(posFile, posLine, posColumn)
+    , Comment(cSeverity, cCode, cMessage)
+    , PositionedComment(pcStartPos , pcEndPos , pcComment, pcFix)
+    , ColorOption(ColorAuto, ColorAlways, ColorNever)
+    , TokenComment(tcId, tcComment, tcFix)
+    , emptyCheckResult
+    , newParseResult
+    , newAnalysisSpec
+    , newAnalysisResult
+    , newFormatterOptions
+    , newPosition
+    , newTokenComment
+    , mockedSystemInterface
+    , mockRcFile
+    , newParseSpec
+    , emptyCheckSpec
+    , newPositionedComment
+    , newComment
+    , Fix(fixReplacements)
+    , newFix
+    , InsertionPoint(InsertBefore, InsertAfter)
+    , Replacement(repStartPos, repEndPos, repString, repPrecedence, repInsertionPoint)
+    , newReplacement
+    , CheckDescription(cdName, cdDescription, cdPositive, cdNegative)
+    , newCheckDescription
+    ) where
+
+import ShellCheck.AST
+
+import Control.DeepSeq
+import Control.Monad.Identity
+import Data.List
+import Data.Monoid
+import Data.Ord
+import Data.Semigroup
+import GHC.Generics (Generic)
+import qualified Data.Map as Map
+
+
+data SystemInterface m = SystemInterface {
+    -- Read a file by filename, or return an error
+    siReadFile :: String -> m (Either ErrorMessage String),
+    -- Given:
+    --   the current script,
+    --   a list of source-path annotations in effect,
+    --   and a sourced file,
+    --   find the sourced file
+    siFindSource :: String -> [String] -> String -> m FilePath,
+    -- Get the configuration file (name, contents) for a filename
+    siGetConfig :: String -> m (Maybe (FilePath, String))
+}
+
+-- ShellCheck input and output
+data CheckSpec = CheckSpec {
+    csFilename :: String,
+    csScript :: String,
+    csCheckSourced :: Bool,
+    csIgnoreRC :: Bool,
+    csExcludedWarnings :: [Integer],
+    csIncludedWarnings :: Maybe [Integer],
+    csShellTypeOverride :: Maybe Shell,
+    csMinSeverity :: Severity,
+    csOptionalChecks :: [String]
+} deriving (Show, Eq)
+
+data CheckResult = CheckResult {
+    crFilename :: String,
+    crComments :: [PositionedComment]
+} deriving (Show, Eq)
+
+emptyCheckResult :: CheckResult
+emptyCheckResult = CheckResult {
+    crFilename = "",
+    crComments = []
+}
+
+emptyCheckSpec :: CheckSpec
+emptyCheckSpec = CheckSpec {
+    csFilename = "",
+    csScript = "",
+    csCheckSourced = False,
+    csIgnoreRC = False,
+    csExcludedWarnings = [],
+    csIncludedWarnings = Nothing,
+    csShellTypeOverride = Nothing,
+    csMinSeverity = StyleC,
+    csOptionalChecks = []
+}
+
+newParseSpec :: ParseSpec
+newParseSpec = ParseSpec {
+    psFilename = "",
+    psScript = "",
+    psCheckSourced = False,
+    psIgnoreRC = False,
+    psShellTypeOverride = Nothing
+}
+
+-- Parser input and output
+data ParseSpec = ParseSpec {
+    psFilename :: String,
+    psScript :: String,
+    psCheckSourced :: Bool,
+    psIgnoreRC :: Bool,
+    psShellTypeOverride :: Maybe Shell
+} deriving (Show, Eq)
+
+data ParseResult = ParseResult {
+    prComments :: [PositionedComment],
+    prTokenPositions :: Map.Map Id (Position, Position),
+    prRoot :: Maybe Token
+} deriving (Show, Eq)
+
+newParseResult :: ParseResult
+newParseResult = ParseResult {
+    prComments = [],
+    prTokenPositions = Map.empty,
+    prRoot = Nothing
+}
+
+-- Analyzer input and output
+data AnalysisSpec = AnalysisSpec {
+    asScript :: Token,
+    asShellType :: Maybe Shell,
+    asFallbackShell :: Maybe Shell,
+    asExecutionMode :: ExecutionMode,
+    asCheckSourced :: Bool,
+    asOptionalChecks :: [String],
+    asTokenPositions :: Map.Map Id (Position, Position)
+}
+
+newAnalysisSpec token = AnalysisSpec {
+    asScript = token,
+    asShellType = Nothing,
+    asFallbackShell = Nothing,
+    asExecutionMode = Executed,
+    asCheckSourced = False,
+    asOptionalChecks = [],
+    asTokenPositions = Map.empty
+}
+
+newtype AnalysisResult = AnalysisResult {
+    arComments :: [TokenComment]
+}
+
+newAnalysisResult = AnalysisResult {
+    arComments = []
+}
+
+-- Formatter options
+data FormatterOptions = FormatterOptions {
+    foColorOption :: ColorOption,
+    foWikiLinkCount :: Integer
+}
+
+newFormatterOptions = FormatterOptions {
+    foColorOption = ColorAuto,
+    foWikiLinkCount = 3
+}
+
+data CheckDescription = CheckDescription {
+    cdName :: String,
+    cdDescription :: String,
+    cdPositive :: String,
+    cdNegative :: String
+    }
+
+newCheckDescription = CheckDescription {
+    cdName = "",
+    cdDescription = "",
+    cdPositive = "",
+    cdNegative = ""
+    }
+
+-- Supporting data types
+data Shell = Ksh | Sh | Bash | Dash deriving (Show, Eq)
+data ExecutionMode = Executed | Sourced deriving (Show, Eq)
+
+type ErrorMessage = String
+type Code = Integer
+
+data Severity = ErrorC | WarningC | InfoC | StyleC
+    deriving (Show, Eq, Ord, Generic, NFData)
+data Position = Position {
+    posFile :: String,    -- Filename
+    posLine :: Integer,   -- 1 based source line
+    posColumn :: Integer  -- 1 based source column, where tabs are 8
+} deriving (Show, Eq, Generic, NFData, Ord)
+
+newPosition :: Position
+newPosition = Position {
+    posFile   = "",
+    posLine   = 1,
+    posColumn = 1
+}
+
+data Comment = Comment {
+    cSeverity :: Severity,
+    cCode     :: Code,
+    cMessage  :: String
+} deriving (Show, Eq, Generic, NFData)
+
+newComment :: Comment
+newComment = Comment {
+    cSeverity = StyleC,
+    cCode     = 0,
+    cMessage  = ""
+}
+
+-- only support single line for now
+data Replacement = Replacement {
+    repStartPos :: Position,
+    repEndPos :: Position,
+    repString :: String,
+    -- Order in which the replacements should happen: highest precedence first.
+    repPrecedence :: Int,
+    -- Whether to insert immediately before or immediately after the specified region.
+    repInsertionPoint :: InsertionPoint
+} deriving (Show, Eq, Generic, NFData)
+
+data InsertionPoint = InsertBefore | InsertAfter
+    deriving (Show, Eq, Generic, NFData)
+
+instance Ord Replacement where
+    compare r1 r2 = (repStartPos r1) `compare` (repStartPos r2)
+
+newReplacement = Replacement {
+    repStartPos = newPosition,
+    repEndPos = newPosition,
+    repString = "",
+    repPrecedence = 1,
+    repInsertionPoint = InsertAfter
+}
+
+data Fix = Fix {
+    fixReplacements :: [Replacement]
+} deriving (Show, Eq, Generic, NFData)
+
+newFix = Fix {
+    fixReplacements = []
+}
+
+data PositionedComment = PositionedComment {
+    pcStartPos :: Position,
+    pcEndPos   :: Position,
+    pcComment  :: Comment,
+    pcFix      :: Maybe Fix
+} deriving (Show, Eq, Generic, NFData)
+
+newPositionedComment :: PositionedComment
+newPositionedComment = PositionedComment {
+    pcStartPos = newPosition,
+    pcEndPos   = newPosition,
+    pcComment  = newComment,
+    pcFix      = Nothing
+}
+
+data TokenComment = TokenComment {
+    tcId :: Id,
+    tcComment :: Comment,
+    tcFix :: Maybe Fix
+} deriving (Show, Eq, Generic, NFData)
+
+newTokenComment = TokenComment {
+    tcId = Id 0,
+    tcComment = newComment,
+    tcFix = Nothing
+}
+
+data ColorOption =
+    ColorAuto
+    | ColorAlways
+    | ColorNever
+  deriving (Ord, Eq, Show)
+
+-- For testing
+mockedSystemInterface :: [(String, String)] -> SystemInterface Identity
+mockedSystemInterface files = SystemInterface {
+    siReadFile = rf,
+    siFindSource = fs,
+    siGetConfig = const $ return Nothing
+}
+  where
+    rf file =
+        case filter ((== file) . fst) files of
+            [] -> return $ Left "File not included in mock."
+            [(_, contents)] -> return $ Right contents
+    fs _ _ file = return file
+
+mockRcFile rcfile mock = mock {
+    siGetConfig = const . return $ Just (".shellcheckrc", rcfile)
+}
+

src/ShellCheck/Regex.hs

@@ -0,0 +1,80 @@
+{-
+    Copyright 2012-2019 Vidar Holen
+
+    This file is part of ShellCheck.
+    https://www.shellcheck.net
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+-}
+{-# LANGUAGE FlexibleContexts #-}
+
+-- Basically Text.Regex based on regex-tdfa instead of the buggy regex-posix.
+module ShellCheck.Regex where
+
+import Data.List
+import Data.Maybe
+import Control.Monad
+import Text.Regex.TDFA
+
+-- Precompile the regex
+mkRegex :: String -> Regex
+mkRegex str =
+    let make :: String -> Regex
+        make = makeRegex
+    in
+        make str
+
+-- Does the regex match?
+matches :: String -> Regex -> Bool
+matches = flip match
+
+-- Get all subgroups of the first match
+matchRegex :: Regex -> String -> Maybe [String]
+matchRegex re str = do
+    (_, _, _, groups) <- matchM re str :: Maybe (String,String,String,[String])
+    return groups
+
+-- Get all full matches
+matchAllStrings :: Regex -> String -> [String]
+matchAllStrings re = unfoldr f
+  where
+    f :: String -> Maybe (String, String)
+    f str = do
+        (_, match, rest, _) <- matchM re str :: Maybe (String, String, String, [String])
+        return (match, rest)
+
+-- Get all subgroups from all matches
+matchAllSubgroups :: Regex -> String -> [[String]]
+matchAllSubgroups re = unfoldr f
+  where
+    f :: String -> Maybe ([String], String)
+    f str = do
+        (_, _, rest, groups) <- matchM re str :: Maybe (String, String, String, [String])
+        return (groups, rest)
+
+-- Replace regex in input with string
+subRegex :: Regex -> String -> String -> String
+subRegex re input replacement = f input
+  where
+    f str = fromMaybe str $ do
+        (before, match, after) <- matchM re str :: Maybe (String, String, String)
+        when (null match) $ error ("Internal error: substituted empty in " ++ str)
+        return $ before ++ replacement ++ f after
+
+-- Split a string based on a regex.
+splitOn :: String -> Regex -> [String]
+splitOn input re =
+    case matchM re input :: Maybe (String, String, String) of
+        Just (before, match, after) -> before : after `splitOn` re
+        Nothing -> [input]

stack.yaml

@@ -0,0 +1,35 @@
+# This file was automatically generated by stack init
+# For more information, see: https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
+resolver: lts-13.26
+
+# Local packages, usually specified by relative directory name
+packages:
+- '.'
+# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
+extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: >= 1.0.0
+
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

striptests

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+# This file strips all unit tests from ShellCheck, removing
+# the dependency on QuickCheck and Template Haskell and
+# reduces the binary size considerably.
+set -o pipefail
+
+sponge() {
+  local data
+  data="$(cat)"
+  printf '%s\n' "$data" > "$1"
+}
+
+modify() {
+  if ! "${@:2}" < "$1" | sponge "$1"
+  then
+    {
+      printf 'Failed to modify %s: ' "$1"
+      printf '%q ' "${@:2}"
+      printf '\n'
+    } >&2
+    exit 1
+  fi
+}
+
+detestify() {
+  printf '%s\n' '-- AUTOGENERATED from ShellCheck by striptests. Do not modify.'
+  awk '
+    BEGIN {
+      state = 0;
+    }
+
+    /LANGUAGE TemplateHaskell/ { next; }
+    /^import.*Test\./ { next; }
+
+    /^module/ {
+      sub(/,[^,)]*runTests/, "");
+    }
+
+    # Delete tests
+    /^prop_/ { state = 1; next; }
+
+    # ..and any blank lines following them.
+    state == 1 && /^ / { next; }
+
+    # Template Haskell marker
+    /^return / {
+      exit;
+    }
+
+    { state = 0; print; }
+    '
+}
+
+
+
+if [[ ! -e 'ShellCheck.cabal' ]]
+then
+  echo "Run me from the ShellCheck directory." >&2
+  exit 1
+fi
+
+if [[ -d '.git' ]] && ! git diff --exit-code > /dev/null 2>&1
+then
+  echo "You have local changes! These may be overwritten." >&2
+  exit 2
+fi
+
+modify 'ShellCheck.cabal' sed -e '
+  /QuickCheck/d
+  /^test-suite/{ s/.*//; q; }
+  '
+
+find . -name '.git' -prune -o -type f -name '*.hs' -print |
+  while IFS= read -r file
+  do
+    modify "$file" detestify
+  done
+

test/buildtest

@@ -0,0 +1,35 @@
+#!/bin/bash
+# This script configures, builds and runs tests.
+# It's meant for automatic cross-distro testing.
+
+die() { echo "$*" >&2; exit 1; }
+
+[ -e "ShellCheck.cabal" ] ||
+  die "ShellCheck.cabal not in current dir"
+command -v cabal ||
+  die "cabal is missing"
+
+cabal update ||
+  die "can't update"
+cabal install --dependencies-only --enable-tests ||
+  die "can't install dependencies"
+cabal configure --enable-tests ||
+  die "configure failed"
+cabal build ||
+  die "build failed"
+cabal test ||
+  die "test failed"
+
+dist/build/shellcheck/shellcheck - << 'EOF' || die "execution failed"
+#!/bin/sh
+echo "Hello World"
+EOF
+
+dist/build/shellcheck/shellcheck - << 'EOF' && die "negative execution failed"
+#!/bin/sh
+echo $1
+EOF
+
+
+echo "Success"
+exit 0

test/check_release

@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+
+failed=0
+fail() {
+  echo "$(tput setaf 1)$*$(tput sgr0)"
+  failed=1
+}
+
+if git diff | grep -q ""
+then
+  fail "There are uncommited changes"
+fi
+
+current=$(git tag --points-at)
+if [[ -z "$current" ]]
+then
+  fail "No git tag on the current commit"
+  echo "Create one with:   git tag -a v0.0.0"
+fi
+
+if [[ "$current" != v* ]]
+then
+  fail "Bad tag format: expected v0.0.0"
+fi
+
+if [[ "$(git cat-file -t "$current")" != "tag" ]]
+then
+  fail "Current tag is not annotated (required for Snap)."
+fi
+
+if [[ "$(git tag --points-at master)" != "$current" ]]
+then
+  fail "You are not on master"
+fi
+
+version=${current#v}
+if ! grep "Version:" ShellCheck.cabal | grep -qFw "$version"
+then
+  fail "The cabal file does not match tag version $version"
+fi
+
+if ! grep -qF "## $current" CHANGELOG.md
+then
+  fail "CHANGELOG.md does not contain '## $current'"
+fi
+
+if [[ $(git log -1 --pretty=%B) != "Stable version "* ]]
+then
+  fail "Expected git log message to be 'Stable version ...'"
+fi
+
+i=1 j=1
+cat << EOF
+
+Manual Checklist
+
+$((i++)). Make sure none of the automated checks above failed
+$((i++)). Make sure Travis build currently passes: https://travis-ci.org/koalaman/shellcheck
+$((i++)). Make sure SnapCraft build currently works: https://build.snapcraft.io/user/koalaman
+$((i++)). Run test/distrotest to ensure that most distros can build OOTB.
+$((i++)). Format and read over the manual for bad formatting and outdated info.
+$((i++)). Make sure the Hackage package builds, so that all files are 
+
+Release Steps
+
+$((j++)). \`cabal sdist\` to generate a Hackage package
+$((j++)). \`git push --follow-tags\` to push commit
+$((j++)). Wait for Travis to build
+$((j++)). Verify release:
+  a. Check that the new versions are uploaded: https://shellcheck.storage.googleapis.com/index.html
+  b. Check that the docker images have version tags: https://hub.docker.com/u/koalaman
+$((j++)). If no disaster, upload to Hackage: http://hackage.haskell.org/upload
+$((j++)). Push a new commit that updates CHANGELOG.md
+EOF
+exit "$failed"

test/distrotest

@@ -0,0 +1,80 @@
+#!/bin/bash
+# This script runs 'buildtest' on each of several distros
+# via Docker.
+set -o pipefail
+
+exec 3>&1 4>&2
+die() { echo "$*" >&4; exit 1; }
+
+[ -e "ShellCheck.cabal" ] || die "ShellCheck.cabal not in this dir"
+
+[ "$1" = "--run" ] || {
+cat << EOF
+This script pulls multiple distros via Docker and compiles
+ShellCheck and dependencies for each one. It takes hours,
+and is still highly experimental.
+
+Make sure you're plugged in and have screen/tmux in place,
+then re-run with $0 --run to continue.
+
+Also note that 'dist' will be deleted.
+EOF
+exit 0
+}
+
+echo "Deleting 'dist'..."
+rm -rf dist
+
+log=$(mktemp) || die "Can't create temp file"
+date >> "$log" || die "Can't write to log"
+
+echo "Logging to $log" >&3
+exec >> "$log" 2>&1
+
+final=0
+while read -r distro setup
+do
+  [[ "$distro" = "#"* || -z "$distro" ]] && continue
+  printf '%s ' "$distro" >&3
+  docker pull "$distro" || die "Can't pull $distro"
+  printf 'pulled. ' >&3
+
+  tmp=$(mktemp -d) || die "Can't make temp dir"
+  cp -r . "$tmp/" || die "Can't populate test dir"
+  printf 'Result: ' >&3
+  < /dev/null docker run -v "$tmp:/mnt" "$distro" sh -c "
+    $setup
+    cd /mnt || exit 1
+    test/buildtest
+    "
+  ret=$?
+  if [ "$ret" = 0 ]
+  then
+    echo "OK" >&3
+  else
+    echo "FAIL with $ret. See $log" >&3
+    final=1
+  fi
+  rm -rf "$tmp"
+done << EOF
+# Docker tag          Setup command
+debian:stable         apt-get update && apt-get install -y cabal-install
+debian:testing        apt-get update && apt-get install -y cabal-install
+ubuntu:latest         apt-get update && apt-get install -y cabal-install
+opensuse/leap:latest  zypper install -y cabal-install ghc
+
+# Other Ubuntu versions we want to support
+ubuntu:19.04          apt-get update && apt-get install -y cabal-install
+ubuntu:18.10          apt-get update && apt-get install -y cabal-install
+
+# Misc Haskell including current and latest Stack build
+ubuntu:18.10          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
+haskell:latest        true
+
+# Known to currently fail
+centos:latest         yum install -y epel-release && yum install -y cabal-install
+fedora:latest         dnf install -y cabal-install
+archlinux/base:latest pacman -S -y --noconfirm cabal-install ghc-static base-devel
+EOF
+
+exit "$final"

test/shellcheck.hs

@@ -2,15 +2,29 @@ module Main where
 
 import Control.Monad
 import System.Exit
-import qualified ShellCheck.Simple
 import qualified ShellCheck.Analytics
+import qualified ShellCheck.AnalyzerLib
+import qualified ShellCheck.Checker
+import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.Custom
+import qualified ShellCheck.Checks.ShellSupport
+import qualified ShellCheck.Fixer
+import qualified ShellCheck.Formatter.Diff
 import qualified ShellCheck.Parser
 
 main = do
     putStrLn "Running ShellCheck tests..."
-    results <- sequence [ShellCheck.Simple.runTests,
-                         ShellCheck.Analytics.runTests,
-                         ShellCheck.Parser.runTests]
-    if and results then exitSuccess
-     else exitFailure
-
+    results <- sequence [
+        ShellCheck.Analytics.runTests
+        ,ShellCheck.AnalyzerLib.runTests
+        ,ShellCheck.Checker.runTests
+        ,ShellCheck.Checks.Commands.runTests
+        ,ShellCheck.Checks.Custom.runTests
+        ,ShellCheck.Checks.ShellSupport.runTests
+        ,ShellCheck.Fixer.runTests
+        ,ShellCheck.Formatter.Diff.runTests
+        ,ShellCheck.Parser.runTests
+      ]
+    if and results
+      then exitSuccess
+      else exitFailure

test/stacktest

@@ -0,0 +1,27 @@
+#!/bin/bash
+# This script builds ShellCheck through `stack` using
+# various resolvers. It's run via distrotest.
+
+resolvers=(
+  nightly-"$(date -d "3 days ago" +"%Y-%m-%d")"
+)
+
+die() { echo "$*" >&2; exit 1; }
+
+[ -e "ShellCheck.cabal" ] ||
+  die "ShellCheck.cabal not in current dir"
+[ -e "stack.yaml" ] ||
+  die "stack.yaml not in current dir"
+command -v stack ||
+  die "stack is missing"
+
+stack setup        || die "Failed to setup with default resolver"
+stack build --test || die "Failed to build/test with default resolver"
+
+for resolver in "${resolvers[@]}"
+do
+  stack --resolver="$resolver" setup        || die "Failed to setup $resolver"
+  stack --resolver="$resolver" build --test || die "Failed build/test with $resolver!"
+done
+
+echo "Success"