Stable version 0.9.0

This release is dedicated to Mindustry: the most fun you can
have with open source (outside of shell scripting of course).

.compile_binaries

@@ -1,73 +0,0 @@
-#!/bin/bash
-
-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
-}
-
-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
-}
-
-build_windows() {
-  # Windows .exe
-  docker run -v "$PWD:/appdata" koalaman/winghc cuib
-  for tag in $TAGS
-  do 
-    cp "dist/build/ShellCheck/shellcheck.exe" "deploy/shellcheck-$tag.exe"; 
-  done
-}
-
-build_osx() {
-  # Darwin x86_64 executable
-  brew update
-  brew install cabal-install pandoc gnu-tar
-  sudo ln -sf /usr/local/bin/gsha512sum /usr/local/bin/sha512sum
-  sudo ln -sf /usr/local/bin/gtar /usr/local/bin/tar
-  export PATH="/usr/local/bin:$PATH"
-
-  cabal update
-  cabal install --dependencies-only
-  cabal build shellcheck
-
-  # Cabal 3 no longer has a predictable output path
-  path="$(find . -name 'shellcheck' -type f -perm +111)"
-  [[ -e "$path" ]]
-
-  for tag in $TAGS
-  do 
-    cp "$path" "deploy/shellcheck-$tag.darwin-x86_64";
-  done
-}
-

.github/ISSUE_TEMPLATE.md

@@ -2,10 +2,10 @@
 - 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
+- [ ] I tried on https://www.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
+- [ ] https://www.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
 
 

.github/workflows/build.yml

@@ -0,0 +1,131 @@
+name: Build ShellCheck
+
+# Run this workflow every time a new commit pushed to your repository
+on: push
+
+jobs:
+  package_source:
+    name: Package Source Code
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-mark manual ghc # Don't bother installing ghc just to tar up source
+          sudo apt-get install cabal-install
+
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Deduce tags
+        run: |
+          mkdir source
+          echo "latest" > source/tags
+          if tag=$(git describe --exact-match --tags)
+          then
+            echo "stable" >> source/tags
+            echo "$tag" >> source/tags
+          fi
+          cat source/tags
+
+      - name: Package Source
+        run: |
+          grep "stable" source/tags || ./setgitversion
+          cabal sdist
+          mv dist-newstyle/sdist/*.tar.gz source/source.tar.gz
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: source
+          path: source/
+
+  build_source:
+    name: Build Source Code
+    needs: package_source
+    strategy:
+      matrix:
+        build: [linux.x86_64, linux.aarch64, linux.armv6hf, darwin.x86_64, windows.x86_64]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Download artifacts
+        uses: actions/download-artifact@v3
+
+      - name: Build source
+        run: |
+          mkdir -p bin
+          mkdir -p bin/${{matrix.build}}
+          ( cd bin && ../build/run_builder ../source/source.tar.gz ../build/${{matrix.build}} )
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: bin
+          path: bin/
+
+  package_binary:
+    name: Package Binaries
+    needs: build_source
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Download artifacts
+        uses: actions/download-artifact@v3
+
+      - name: Work around GitHub permissions bug
+        run: chmod +x bin/*/shellcheck*
+
+      - name: Package binaries
+        run: |
+          export TAGS="$(cat source/tags)"
+          mkdir -p deploy
+          cp -r bin/* deploy
+          cd deploy
+          ../.prepare_deploy
+          rm -rf */ README* LICENSE*
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: deploy
+          path: deploy/
+
+  deploy:
+    name: Deploy binaries
+    needs: package_binary
+    runs-on: ubuntu-latest
+    environment: Deploy
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Download artifacts
+        uses: actions/download-artifact@v3
+
+      - name: Upload to GitHub
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          export TAGS="$(cat source/tags)"
+          ./.github_deploy
+
+      - name: Waiting for GitHub to replicate uploaded releases
+        run: |
+          sleep 300
+
+      - name: Upload to Docker Hub
+        env:
+          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+          DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
+          DOCKER_EMAIL: ${{ secrets.DOCKER_EMAIL }}
+          DOCKER_BASE: ${{ secrets.DOCKER_USERNAME }}/shellcheck
+        run: |
+          export TAGS="$(cat source/tags)"
+          ( source ./.multi_arch_docker && set -eux && multi_arch_docker::main )

.github_deploy

@@ -2,39 +2,10 @@
 set -x
 shopt -s extglob
 
-if [[ "$TRAVIS_SECURE_ENV_VARS" != "true" ]]
-then
-  echo >&2 "Missing TRAVIS_SECURE_ENV_VARS. Skipping GitHub deployment."
-  exit 0
-fi
-
-install_deps() {
-  version="2.7.0"  # 2.14.1 fails to overwrite duplicates
-  case "$(uname)" in
-    Linux)
-      sudo apt-get update
-      sudo apt-get install curl
-      curl -L "https://github.com/github/hub/releases/download/v$version/hub-linux-amd64-$version.tgz" | tar xvz --strip-components=1 "hub-linux-amd64-$version/bin/hub"
-      ;;
-    Darwin)
-      curl -L "https://github.com/github/hub/releases/download/v$version/hub-darwin-amd64-$version.tgz" | tar xvz --strip-components=1 "hub-darwin-amd64-$version/bin/hub"
-      ;;
-    *)
-      echo "Unknown: $(uname)"
-      exit 1
-      ;;
-  esac
-
-  hub_path="$PWD/bin/hub"
-  hub() {
-    "$hub_path" "$@"
-  }
-}
-install_deps
-
 export EDITOR="touch"
 
 # Sanity check
+gh --version || exit 1
 hub release show latest || exit 1
 
 for tag in $TAGS
@@ -50,8 +21,8 @@ do
   for file in deploy/*
   do
     [[ $file == *.@(xz|gz|zip) ]] || continue
-    files+=(-a "$file")
+    [[ $file == *"$tag"* ]] || continue
+    files+=("$file")
   done
-  hub release edit "${files[@]}" "$tag" || exit 1
+  gh release upload "$tag" "${files[@]}" --clobber || exit 1
 done
-

.multi_arch_docker

@@ -1,12 +1,6 @@
 #!/bin/bash
 # This script builds and deploys multi-architecture docker images from the
-# binaries previously built and deployed to GCS by the Travis pipeline.
-
-if [[ "$TRAVIS_SECURE_ENV_VARS" != "true" ]]
-then
-  echo >&2 "Missing TRAVIS_SECURE_ENV_VARS. Skipping Docker builds."
-  exit 0
-fi
+# binaries previously built and deployed to GitHub.
 
 function multi_arch_docker::install_docker_buildx() {
   # Install up-to-date version of docker, with buildx support.
@@ -108,6 +102,5 @@ function multi_arch_docker::main() {
   multi_arch_docker::install_docker_buildx
   multi_arch_docker::login_to_docker_hub
   multi_arch_docker::build_and_push_all
-  set +x
   multi_arch_docker::test_all
 }

.prepare_deploy

@@ -1,8 +1,9 @@
 #!/bin/bash
-# This script packages up Travis compiled binaries
+# This script packages up compiled binaries
 set -ex
-shopt -s nullglob
-cd deploy
+shopt -s nullglob extglob
+
+ls -l
 
 cp ../LICENSE LICENSE.txt
 sed -e $'s/$/\r/' > README.txt << END
@@ -22,44 +23,32 @@ This binary was compiled on $(date -u).
 $(git log -n 3)
 END
 
-for file in ./*.exe
+for dir in */
 do
-  zip "${file%.*}.zip" README.txt LICENSE.txt "$file"
+  cp LICENSE.txt README.txt "$dir"
 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
+echo "Tags are $TAGS"
 
-for file in *.linux-aarch64
+for tag in $TAGS
 do
-  base="${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 dir in windows.*/
+  do
+    ( cd "$dir" && zip "../shellcheck-$tag.zip" * )
+  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"
+  for dir in {linux,darwin}.*/
+  do
+    base="${dir%/}"
+    ( cd "$dir" && tar -cJf "../shellcheck-$tag.$base.tar.xz" --transform="s:^:shellcheck-$tag/:" * )
+  done
 done
 
 for file in ./*
 do
+  [[ -f "$file" ]] || continue
   sha512sum "$file" > "$file.sha512sum"
 done
+
+ls -l

.travis.yml

@@ -1,64 +0,0 @@
-language: shell
-os: linux
-
-services:
-  - docker
-
-jobs:
-  include:
-    - stage: Build
-
-      # This must weirdly not have a dash, otherwise an empty job is created
-      env: BUILD=linux
-    - env: BUILD=windows
-    - env: BUILD=armv6hf
-    - env: BUILD=aarch64
-    - env: BUILD=osx
-      os: osx
-
-    - stage: Deploy docker image
-      # Deploy only for pushes to master branch, not other branches, not PRs.
-      if: type = push
-      script:
-        - source ./.multi_arch_docker
-        - set -ex; multi_arch_docker::main; set +x
-
-# This is in global context and runs for every stage that doesn't override it.
-before_install: |
-  DOCKER_BASE="$DOCKER_USERNAME/shellcheck"
-  DOCKER_BUILDS=""
-  export TAGS=""
-  test "$TRAVIS_BRANCH" = master && TAGS="$TAGS latest" || true
-  test -n "$TRAVIS_TAG"          && TAGS="$TAGS stable $TRAVIS_TAG" || true
-  echo "Tags are $TAGS"
-
-# This is in global context and runs for every stage that doesn't override it.
-script:
-  - mkdir -p deploy
-  - source ./.compile_binaries
-  - ./striptests
-  - set -ex; build_"$BUILD"; set +x;
-  - ./.prepare_deploy
-  - ./.github_deploy
-
-# This is in global context and runs for every stage that doesn't override it.
-after_failure: |
-  id
-  pwd
-  df -h
-  find . -name '*.log' -type f -exec grep "" /dev/null {} +
-  find . -ls
-
-# This is in global context and runs for every stage that doesn't override it.
-deploy:
-  provider: gcs
-  skip_cleanup: true
-  access_key_id: GOOG7MDN7WEH6IIGBDCA
-  secret_access_key:
-    secure: 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
-  bucket: shellcheck-private
-  local_dir: deploy
-  on:
-    repo: koalaman/shellcheck
-    condition: $TRAVIS_BUILD_STAGE_NAME = Build
-    all_branches: true

CHANGELOG.md

@@ -1,3 +1,91 @@
+## v0.9.0 - 2022-12-12
+### Added
+- SC2316: Warn about 'local readonly foo' and similar (thanks, patrickxia!)
+- SC2317: Warn about unreachable commands
+- SC2318: Warn about backreferences in 'declare x=1 y=$x'
+- SC2319/SC2320: Warn when $? refers to echo/printf/[ ]/[[ ]]/test
+- SC2321: Suggest removing $((..)) in array[$((idx))]=val
+- SC2322: Suggest collapsing double parentheses in arithmetic contexts
+- SC2323: Suggest removing wrapping parentheses in a[(x+1)]=val
+
+### Fixed
+- SC2086: Now uses DFA to make more accurate predictions about values
+- SC2086: No longer warns about values declared as integer with declare -i
+
+### Changed
+- ShellCheck now has a Data Flow Analysis engine to make smarter decisions
+  based on control flow rather than just syntax. Existing checks will
+  gradually start using it, which may cause them to trigger differently
+  (but more accurately).
+- Values in directives/shellcheckrc can now be quoted with '' or ""
+
+
+## v0.8.0 - 2021-11-06
+### Added
+- `disable=all` now conveniently disables all warnings
+- `external-sources=true` directive can be added to .shellcheckrc to make
+  shellcheck behave as if `-x` was specified.
+- Optional `check-extra-masked-returns` for pointing out commands with
+  suppressed exit codes (SC2312).
+- Optional `require-double-brackets` for recommending \[\[ ]] (SC2292).
+- SC2286-SC2288: Warn when command name ends in a symbol like `/.)'"`
+- SC2289: Warn when command name contains tabs or linefeeds
+- SC2291: Warn about repeated unquoted spaces between words in echo
+- SC2292: Suggest [[ over [ in Bash/Ksh scripts (optional)
+- SC2293/SC2294: Warn when calling `eval` with arrays
+- SC2295: Warn about "${x#$y}" treating $y as a pattern when not quoted
+- SC2296-SC2301: Improved warnings for bad parameter expansions
+- SC2302/SC2303: Warn about loops over array values when using them as keys
+- SC2304-SC2306: Warn about unquoted globs in expr arguments
+- SC2307: Warn about insufficient number of arguments to expr
+- SC2308: Suggest other approaches for non-standard expr extensions
+- SC2313: Warn about `read` with unquoted, array indexed variable
+
+### Fixed
+- SC2102 about repetitions in ranges no longer triggers on [[ -v arr[xx] ]]
+- SC2155 now recognizes `typeset` and local read-only `declare` statements
+- SC2181 now tries to avoid triggering for error handling functions
+- SC2290: Warn about misused = in declare & co, which were not caught by SC2270+
+- The flag --color=auto no longer outputs color when TERM is "dumb" or unset
+
+### Changed
+- SC2048: Warning about $\* now also applies to ${array[\*]}
+- SC2181 now only triggers on single condition tests like `[ $? = 0 ]`.
+- Quote warnings are now emitted for declaration utilities in sh
+- Leading `_` can now be used to suppress warnings about unused variables
+- TTY output now includes warning level in text as well as color
+
+### Removed
+- SC1004: Literal backslash+linefeed in '' was found to be usually correct
+
+
+## v0.7.2 - 2021-04-19
+### Added
+- `disable` directives can now be a range, e.g. `disable=SC3000-SC4000`
+- SC1143: Warn about line continuations in comments
+- SC2259/SC2260: Warn when redirections override pipes
+- SC2261: Warn about multiple competing redirections
+- SC2262/SC2263: Warn about aliases declared and used in the same parsing unit
+- SC2264: Warn about wrapper functions that blatantly recurse
+- SC2265/SC2266: Warn when using & or | with test statements
+- SC2267: Warn when using xargs -i instead of -I
+- SC2268: Warn about unnecessary x-comparisons like `[ x$var = xval ]`
+
+### Fixed
+- SC1072/SC1073 now respond to disable annotations, though ignoring parse errors
+  is still purely cosmetic and does not allow ShellCheck to continue.
+- Improved error reporting for trailing tokens after ]/]] and compound commands
+- `#!/usr/bin/env -S shell` is now handled correctly
+- Here docs with \r are now parsed correctly and give better warnings
+
+### Changed
+- Assignments are now parsed to spec, without leniency for leading $ or spaces
+- POSIX/dash unsupported feature warnings now have individual SC3xxx codes
+- SC1090: A leading `$x/` or `$(x)/` is now treated as `./` when locating files
+- SC2154: Variables appearing in -z/-n tests are no longer considered unassigned
+- SC2270-SC2285: Improved warnings about misused `=`, e.g. `${var}=42`
+
+
 ## v0.7.1 - 2020-04-04
 ### Fixed
 - `-f diff` no longer claims that it found more issues when it didn't
@@ -138,7 +226,7 @@
 - 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
+- SC2196/SC2197: Warn about deprecated egrep/fgrep
 - SC2195: Warn about unmatchable case branches
 - SC2194: Warn about constant 'case' statements
 - SC2193: Warn about `[[ file.png == *.mp3 ]]` and other unmatchables
@@ -155,7 +243,7 @@
 ### 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
+- Here doc delimiters 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
@@ -168,7 +256,7 @@
 - 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` 
+- 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 ))`
 
@@ -339,7 +427,7 @@
 ### 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` 
+- 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`
@@ -390,7 +478,7 @@
 
 ### Removed
 - Suggestions about using parameter expansion over basename
-- The `jsoncheck` binary. Use `shellcheck -f json` instead. 
+- The `jsoncheck` binary. Use `shellcheck -f json` instead.
 
 
 ## v0.2.0 - 2013-10-27

Dockerfile

@@ -1,29 +0,0 @@
-# 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 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 ShellCheck image
-FROM scratch
-LABEL maintainer="Vidar Holen <vidar@vidarholen.net>"
-WORKDIR /mnt
-COPY --from=build /out /
-ENTRYPOINT ["/bin/shellcheck"]

LICENSE

@@ -1,13 +1,3 @@
-Employer mandated disclaimer:
-
-  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
 
@@ -681,4 +671,4 @@ 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>.
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

README.md

@@ -1,4 +1,5 @@
-[![Build Status](https://travis-ci.org/koalaman/shellcheck.svg?branch=master)](https://travis-ci.org/koalaman/shellcheck)
+[![Build Status](https://github.com/koalaman/shellcheck/actions/workflows/build.yml/badge.svg)](https://github.com/koalaman/shellcheck/actions/workflows/build.yml)
+
 
 # ShellCheck - A shell script static analysis tool
 
@@ -109,11 +110,8 @@ Services and platforms that have ShellCheck pre-installed and ready to use:
 * [Codacy](https://www.codacy.com/)
 * [Code Climate](https://codeclimate.com/)
 * [Code Factor](https://www.codefactor.io/)
-* [Github](https://github.com/features/actions)(only Linux)
-
-Services and platforms with third party plugins:
-
-* [SonarQube](https://www.sonarqube.org/) through [sonar-shellcheck-plugin](https://github.com/emerald-squad/sonar-shellcheck-plugin)
+* [CircleCI](https://circleci.com) via the [ShellCheck Orb](https://circleci.com/orbs/registry/orb/circleci/shellcheck)
+* [Github](https://github.com/features/actions) (only Linux)
 
 Most other services, including [GitLab](https://about.gitlab.com/), let you install
 ShellCheck yourself, either through the system's package manager (see [Installing](#installing)),
@@ -142,13 +140,13 @@ On systems with Stack (installs to `~/.local/bin`):
 
 On Debian based distros:
 
-    apt-get install shellcheck
+    sudo apt 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.
+or get the dependency free [shellcheck-bin](https://aur.archlinux.org/packages/shellcheck-bin/) from the AUR.
 
 On Gentoo based distros:
 
@@ -156,8 +154,8 @@ On Gentoo based distros:
 
 On EPEL based distros:
 
-    yum -y install epel-release
-    yum install ShellCheck
+    sudo yum -y install epel-release
+    sudo yum install ShellCheck
 
 On Fedora based distros:
 
@@ -167,10 +165,14 @@ On FreeBSD:
 
     pkg install hs-ShellCheck
 
-On OS X with homebrew:
+On macOS (OS X) with Homebrew:
 
     brew install shellcheck
 
+Or with MacPorts:
+
+    sudo port install shellcheck
+
 On OpenBSD:
 
     pkg_add shellcheck
@@ -197,6 +199,10 @@ Or Windows (via [scoop](http://scoop.sh)):
 C:\> scoop install shellcheck
 ```
 
+From [conda-forge](https://anaconda.org/conda-forge/shellcheck):
+
+    conda install -c conda-forge shellcheck
+
 From Snap Store:
 
     snap install --channel=edge shellcheck
@@ -220,7 +226,7 @@ Alternatively, you can download pre-compiled binaries for the latest release her
 * [Linux, x86_64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.x86_64.tar.xz) (statically linked)
 * [Linux, armv6hf](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.armv6hf.tar.xz), i.e. Raspberry Pi (statically linked)
 * [Linux, aarch64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.linux.aarch64.tar.xz) aka ARM64 (statically linked)
-* [MacOS, x86_64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.darwin.x86_64.tar.xz)
+* [macOS, x86_64](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.darwin.x86_64.tar.xz)
 * [Windows, x86](https://github.com/koalaman/shellcheck/releases/download/stable/shellcheck-stable.zip)
 
 or see the [GitHub Releases](https://github.com/koalaman/shellcheck/releases) for other releases
@@ -233,6 +239,19 @@ pandoc -s -f markdown-smart -t man shellcheck.1.md -o shellcheck.1
 sudo mv shellcheck.1 /usr/share/man/man1
 ```
 
+### pre-commit
+
+To run ShellCheck via [pre-commit](https://pre-commit.com/), add the hook to your `.pre-commit-config.yaml`:
+
+```
+repos:
+-   repo: https://github.com/koalaman/shellcheck-precommit
+    rev: v0.7.2
+    hooks:
+    -   id: shellcheck
+#       args: ["--severity=warning"]  # Optionally only show errors and warnings
+```
+
 ### Travis CI
 
 Travis CI has now integrated ShellCheck by default, so you don't need to manually install it.
@@ -264,7 +283,7 @@ This section describes how to build ShellCheck from a source directory. ShellChe
 
 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.
+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
 
@@ -339,6 +358,7 @@ 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
+unset var[i]                      # Array index treated as glob
 ```
 
 ### Conditionals
@@ -357,6 +377,7 @@ ShellCheck can recognize many types of incorrect test statements.
 [ grep -q foo file ]              # Command without $(..)
 [[ "$$file" == *.jpg ]]           # Comparisons that can't succeed
 (( 1 -lt 2 ))                     # Using test operators in ((..))
+[ x ] & [ y ] | [ z ]             # Accidental backgrounding and piping
 ```
 
 ### Frequently misused commands
@@ -428,6 +449,8 @@ echo "Hello $name"                # Unassigned lowercase variables
 cmd | read bar; echo $bar         # Assignments in subshells
 cat foo | cp bar                  # Piping to commands that don't read
 printf '%s: %s\n' foo             # Mismatches in printf argument count
+eval "${array[@]}"                # Lost word boundaries in array eval
+for i in "${x[@]}"; do ${x[$i]}   # Using array value as key
 ```
 
 ### Robustness
@@ -452,6 +475,7 @@ ShellCheck will warn when using features not supported by the shebang. For examp
 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
+expr match str regex             # Unportable alias for `expr str : regex`
 trap 'exit 42' sigint            # Unportable signal spec
 cmd &> file                      # Unportable redirection operator
 read foo < /dev/tcp/host/22      # Unportable intercepted files
@@ -472,10 +496,15 @@ 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
+!# bin/bash -x -e                 # Common shebang errors
 echo $((n/180*100))               # Unnecessary loss of precision
 ls *[:digit:].txt                 # Bad character class globs
 sed 's/foo/bar/' file > file      # Redirecting to input
+var2=$var2                        # Variable assigned to itself
+[ x$var = xval ]                  # Antiquated x-comparisons
+ls() { ls -l "$@"; }              # Infinitely recursive wrapper
+alias ls='ls -l'; ls foo          # Alias used before it takes effect
+for x; do for x; do               # Nested loop uses same variable
 while getopts "a" f; do case $f in "b") # Unhandled getopts flags
 ```
 

ShellCheck.cabal

@@ -1,5 +1,5 @@
 Name:             ShellCheck
-Version:          0.7.1
+Version:          0.9.0
 Synopsis:         Shell script analysis tool
 License:          GPL-3
 License-file:     LICENSE
@@ -8,7 +8,7 @@ Author:           Vidar Holen
 Maintainer:       vidar@vidarholen.net
 Homepage:         https://www.shellcheck.net/
 Build-Type:       Simple
-Cabal-Version:    >= 1.8
+Cabal-Version:    1.18
 Bug-reports:      https://github.com/koalaman/shellcheck/issues
 Description:
   The goals of ShellCheck are:
@@ -22,9 +22,11 @@ Description:
   * To point out subtle caveats, corner cases and pitfalls, that may cause an
     advanced user's otherwise working script to fail under future circumstances.
 
+Extra-Doc-Files:
+    README.md
+    CHANGELOG.md
 Extra-Source-Files:
     -- documentation
-    README.md
     shellcheck.1.md
     -- A script to build the man page using pandoc
     manpage
@@ -43,19 +45,26 @@ library
       build-depends:
         semigroups
     build-depends:
-      aeson,
-      array,
-      base >= 4.8.0.0 && < 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-tdfa,
-      QuickCheck >= 2.7.4,
+      -- The lower bounds are based on GHC 7.10.3
+      -- The upper bounds are based on GHC 9.4.3
+      aeson                >= 1.4.0 && < 2.2,
+      array                >= 0.5.1 && < 0.6,
+      base                 >= 4.8.0.0 && < 5,
+      bytestring           >= 0.10.6 && < 0.12,
+      containers           >= 0.5.6 && < 0.7,
+      deepseq              >= 1.4.1 && < 1.5,
+      Diff                 >= 0.4.0 && < 0.5,
+      fgl                  >= 5.7.0 && < 5.9,
+      filepath             >= 1.4.0 && < 1.5,
+      mtl                  >= 2.2.2 && < 2.3,
+      parsec               >= 3.1.14 && < 3.2,
+      QuickCheck           >= 2.14.2 && < 2.15,
+      regex-tdfa           >= 1.2.0 && < 1.4,
+      transformers         >= 0.4.2 && < 0.6,
+
+      -- getXdgDirectory from 1.2.3.0
+      directory            >= 1.2.3 && < 1.4,
+
       -- When cabal supports it, move this to setup-depends:
       process
     exposed-modules:
@@ -64,11 +73,15 @@ library
       ShellCheck.Analytics
       ShellCheck.Analyzer
       ShellCheck.AnalyzerLib
+      ShellCheck.CFG
+      ShellCheck.CFGAnalysis
       ShellCheck.Checker
       ShellCheck.Checks.Commands
+      ShellCheck.Checks.ControlFlow
       ShellCheck.Checks.Custom
       ShellCheck.Checks.ShellSupport
       ShellCheck.Data
+      ShellCheck.Debug
       ShellCheck.Fixer
       ShellCheck.Formatter.Format
       ShellCheck.Formatter.CheckStyle
@@ -80,9 +93,11 @@ library
       ShellCheck.Formatter.Quiet
       ShellCheck.Interface
       ShellCheck.Parser
+      ShellCheck.Prelude
       ShellCheck.Regex
     other-modules:
       Paths_ShellCheck
+    default-language: Haskell98
 
 executable shellcheck
     if impl(ghc < 8.0)
@@ -91,18 +106,21 @@ executable shellcheck
     build-depends:
       aeson,
       array,
-      base >= 4 && < 5,
+      base,
       bytestring,
       containers,
-      deepseq >= 1.4.0.0,
-      Diff >= 0.2.0,
-      directory >= 1.2.3.0,
-      mtl >= 2.2.1,
+      deepseq,
+      Diff,
+      directory,
+      fgl,
+      mtl,
       filepath,
-      parsec >= 3.0,
-      QuickCheck >= 2.7.4,
+      parsec,
+      QuickCheck,
       regex-tdfa,
+      transformers,
       ShellCheck
+    default-language: Haskell98
     main-is: shellcheck.hs
 
 test-suite test-shellcheck
@@ -110,17 +128,19 @@ test-suite test-shellcheck
     build-depends:
       aeson,
       array,
-      base >= 4 && < 5,
+      base,
       bytestring,
       containers,
-      deepseq >= 1.4.0.0,
-      Diff >= 0.2.0,
-      directory >= 1.2.3.0,
-      mtl >= 2.2.1,
+      deepseq,
+      Diff,
+      directory,
+      fgl,
       filepath,
+      mtl,
       parsec,
-      QuickCheck >= 2.7.4,
+      QuickCheck,
       regex-tdfa,
+      transformers,
       ShellCheck
+    default-language: Haskell98
     main-is: test/shellcheck.hs
-

build/README.md

@@ -0,0 +1,13 @@
+This directory contains Dockerfiles for all builds.
+
+A build image will:
+
+* Run on Linux x86\_64 with vanilla Docker (no exceptions)
+* Not contain any software that would restrict easy modification or copying
+* Take a `cabal sdist` style tar.gz of the ShellCheck directory on stdin
+* Output a tar.gz of artifacts on stdout, in a directory named for the arch
+
+This makes it simple to build any release without exotic hardware or software.
+
+An image can be built and tagged using `build_builder`,
+and run on a source tarball using `run_builder`.

build/build_builder

@@ -0,0 +1,12 @@
+#!/bin/sh
+if [ $# -eq 0 ]
+then
+  echo >&2 "No build image directories specified"
+  echo >&2 "Example: $0 build/*/"
+  exit 1
+fi
+
+for dir
+do
+  ( cd "$dir" && docker build -t "$(cat tag)" . ) || exit 1
+done

build/darwin.x86_64/Dockerfile

@@ -0,0 +1,30 @@
+FROM liushuyu/osxcross@sha256:fa32af4677e2860a1c5950bc8c360f309e2a87e2ddfed27b642fddf7a6093b76
+
+ENV TARGET x86_64-apple-darwin18
+ENV TARGETNAME darwin.x86_64
+
+# Build dependencies
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+RUN apt-get update && apt-get install -y ghc automake autoconf llvm curl
+
+# Build GHC
+WORKDIR /ghc
+RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-src.tar.xz" | tar xJ --strip-components=1
+RUN ./boot && ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
+RUN cp mk/flavours/quick-cross.mk mk/build.mk && make -j "$(nproc)"
+RUN make install
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-linux.tar.xz" | tar xJv -C /usr/local/bin
+
+# Due to an apparent cabal bug, we specify our options directly to cabal
+# It won't reuse caches if ghc-options are specified in ~/.cabal/config
+ENV CABALOPTS "--with-ghc=$TARGET-ghc;--with-hc-pkg=$TARGET-ghc-pkg"
+
+# Prebuild the dependencies
+RUN cabal update && IFS=';' && cabal install --dependencies-only $CABALOPTS ShellCheck
+
+# Copy the build script
+COPY build /usr/bin
+
+WORKDIR /scratch
+ENTRYPOINT ["/usr/bin/build"]

build/darwin.x86_64/build

@@ -0,0 +1,14 @@
+#!/bin/sh
+set -xe
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  cabal update
+  ( IFS=';'; cabal build $CABALOPTS )
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  "$TARGET-strip" -Sx "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+} >&2
+tar czv "$TARGETNAME"

build/darwin.x86_64/tag

@@ -0,0 +1 @@
+koalaman/scbuilder-darwin-x86_64

build/linux.aarch64/Dockerfile

@@ -0,0 +1,30 @@
+FROM ubuntu:20.04
+
+ENV TARGET aarch64-linux-gnu
+ENV TARGETNAME linux.aarch64
+
+# Build dependencies
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+RUN apt-get update && apt-get install -y ghc automake autoconf build-essential llvm curl qemu-user-static gcc-$TARGET
+
+# Build GHC
+WORKDIR /ghc
+RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-src.tar.xz" | tar xJ --strip-components=1
+RUN ./boot && ./configure --host x86_64-linux-gnu --build x86_64-linux-gnu --target "$TARGET"
+RUN cp mk/flavours/quick-cross.mk mk/build.mk && make -j "$(nproc)"
+RUN make install
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-linux.tar.xz" | tar xJv -C /usr/local/bin
+
+# Due to an apparent cabal bug, we specify our options directly to cabal
+# It won't reuse caches if ghc-options are specified in ~/.cabal/config
+ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections;--with-ghc=$TARGET-ghc;--with-hc-pkg=$TARGET-ghc-pkg"
+
+# Prebuild the dependencies
+RUN cabal update && IFS=';' && cabal install --dependencies-only $CABALOPTS ShellCheck
+
+# Copy the build script
+COPY build /usr/bin
+
+WORKDIR /scratch
+ENTRYPOINT ["/usr/bin/build"]

build/linux.aarch64/build

@@ -0,0 +1,15 @@
+#!/bin/sh
+set -xe
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  cabal update
+  ( IFS=';'; cabal build $CABALOPTS --enable-executable-static )
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  "$TARGET-strip" -s "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+  qemu-aarch64-static "$TARGETNAME/shellcheck" --version
+} >&2
+tar czv "$TARGETNAME"

build/linux.aarch64/tag

@@ -0,0 +1 @@
+koalaman/scbuilder-linux-aarch64

build/linux.armv6hf/Dockerfile

@@ -0,0 +1,60 @@
+# I've again spent days trying to get a working armv6hf compiler going.
+# God only knows how many recompilations of GCC, GHC, libraries, and
+# ShellCheck itself, has gone into it.
+#
+# I tried Debian's toolchain.  I tried my custom one built according to
+# RPi `gcc -v`. I tried GHC9, glibc, musl, registerised vs not, but
+# nothing has yielded an armv6hf binary that does not immediately
+# segfault on qemu-arm-static or the RPi itself.
+#
+# I then tried the same but with armv7hf. Same story.
+#
+# Emulating the entire userspace with balenalib again?  Very strange build
+# failures where programs would fail to execute with > ~100 arguments.
+#
+# Finally, creating our own appears to work when using a custom QEmu
+# patched to follow execve calls.
+#
+# PS: $100 bounty for getting a RPi1 compatible static build going
+#     with cross-compilation, similar to what the aarch64 build does.
+#
+
+FROM ubuntu:20.04
+
+ENV TARGETNAME linux.armv6hf
+
+# Build QEmu with execve follow support
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+RUN apt-get update
+RUN apt-get install -y build-essential git ninja-build python3 pkg-config libglib2.0-dev libpixman-1-dev
+WORKDIR /build
+RUN git clone --depth 1 https://github.com/koalaman/qemu
+RUN cd qemu && ./configure --static && cd build && ninja qemu-arm
+RUN cp qemu/build/qemu-arm /build/qemu-arm-static
+ENV QEMU_EXECVE 1
+
+# Set up an armv6 userspace
+WORKDIR /
+RUN apt-get install -y debootstrap qemu-user-static
+# We expect this to fail if the host doesn't have binfmt qemu support
+RUN qemu-debootstrap --arch armhf bullseye pi http://mirrordirector.raspbian.org/raspbian || [ -e /pi/etc/issue ]
+RUN cp /build/qemu-arm-static /pi/usr/bin/qemu-arm-static
+RUN printf > /bin/pirun '%s\n' '#!/bin/sh' 'chroot /pi /usr/bin/qemu-arm-static /usr/bin/env "$@"' && chmod +x /bin/pirun
+# If the debootstrap process didn't finish, continue it
+RUN [ ! -e /pi/debootstrap ] || pirun '/debootstrap/debootstrap' --second-stage
+
+# Install deps in the chroot
+RUN pirun apt-get update
+RUN pirun apt-get install -y ghc cabal-install
+
+# Finally we can build the current dependencies. This takes hours.
+ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections;--gcc-options;-Os -Wl,--gc-sections -ffunction-sections -fdata-sections"
+RUN pirun cabal update
+RUN IFS=";" && pirun cabal install --dependencies-only $CABALOPTS ShellCheck
+RUN IFS=';' && pirun cabal install $CABALOPTS --lib fgl
+
+# Copy the build script
+WORKDIR /pi/scratch
+COPY build /pi/usr/bin
+ENTRYPOINT ["/bin/pirun", "/usr/bin/build"]

build/linux.armv6hf/build

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -xe
+cd /scratch
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  # This script does not cabal update because compiling anything new is slow
+  ( IFS=';'; cabal build $CABALOPTS --enable-executable-static )
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  strip -s "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+  "$TARGETNAME/shellcheck" --version
+} >&2
+tar czv "$TARGETNAME"

build/linux.armv6hf/tag

@@ -0,0 +1 @@
+koalaman/scbuilder-linux-armv6hf

build/linux.x86_64/Dockerfile

@@ -0,0 +1,20 @@
+FROM alpine:latest
+
+ENV TARGETNAME linux.x86_64
+
+# Install GHC and cabal
+USER root
+RUN apk add ghc cabal g++ libffi-dev curl bash
+
+# Use ld.bfd instead of ld.gold due to
+# x86_64-linux-gnu/libpthread.a(pthread_cond_init.o)(.note.stapsdt+0x14): error:
+#    relocation refers to local symbol "" [2], which is defined in a discarded section
+ENV CABALOPTS "--ghc-options;-optl-Wl,-fuse-ld=bfd -split-sections -optc-Os -optc-Wl,--gc-sections"
+
+# Other archs pre-build dependencies here, but this one doesn't to detect ecosystem movement
+
+# Copy the build script
+COPY build /usr/bin
+
+WORKDIR /scratch
+ENTRYPOINT ["/usr/bin/build"]

build/linux.x86_64/build

@@ -0,0 +1,15 @@
+#!/bin/sh
+set -xe
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  cabal update
+  ( IFS=';'; cabal build $CABALOPTS --enable-executable-static )
+  find . -name shellcheck -type f -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  strip -s "$TARGETNAME/shellcheck"
+  ls -l "$TARGETNAME"
+  "$TARGETNAME/shellcheck" --version
+} >&2
+tar czv "$TARGETNAME"

build/linux.x86_64/tag

@@ -0,0 +1 @@
+koalaman/scbuilder-linux-x86_64

build/run_builder

@@ -0,0 +1,30 @@
+#!/bin/bash
+if [ $# -lt 2 ]
+then
+  echo >&2 "This script builds a source archive (as produced by cabal sdist)"
+  echo >&2 "Usage: $0 sourcefile.tar.gz builddir..."
+  exit 1
+fi
+
+file=$(realpath "$1")
+shift
+
+if [ ! -e "$file" ]
+then
+  echo >&2 "$file does not exist"
+  exit 1
+fi
+
+set -ex -o pipefail
+
+for dir
+do
+  tagfile="$dir/tag"
+  if [ ! -e "$tagfile" ]
+  then
+    echo >&2 "$tagfile does not exist"
+    exit 2
+  fi
+
+  docker run -i "$(< "$tagfile")" < "$file" | tar xz
+done

build/windows.x86_64/Dockerfile

@@ -0,0 +1,27 @@
+FROM ubuntu:20.04
+
+ENV TARGETNAME windows.x86_64
+
+# We don't need wine32, even though it complains
+USER root
+ENV DEBIAN_FRONTEND noninteractive
+RUN apt-get update && apt-get install -y curl busybox wine winbind
+
+# Fetch Windows version, will be available under z:\haskell
+WORKDIR /haskell
+RUN curl -L "https://downloads.haskell.org/~ghc/8.10.4/ghc-8.10.4-x86_64-unknown-mingw32.tar.xz" | tar xJ --strip-components=1
+WORKDIR /haskell/bin
+RUN curl -L "https://downloads.haskell.org/~cabal/cabal-install-3.2.0.0/cabal-install-3.2.0.0-x86_64-unknown-mingw32.zip" | busybox unzip -
+RUN curl -L "https://curl.se/windows/dl-7.84.0/curl-7.84.0-win64-mingw.zip" | busybox unzip - && mv curl-7.84.0-win64-mingw/bin/* .
+ENV WINEPATH /haskell/bin
+
+# It's unknown whether Cabal on Windows suffers from the same issue
+# that necessitated this but I don't care enough to find out
+ENV CABALOPTS "--ghc-options;-split-sections -optc-Os -optc-Wl,--gc-sections"
+
+# Precompile some deps to speed up later builds
+RUN wine /haskell/bin/cabal.exe update && IFS=';' && wine /haskell/bin/cabal.exe install --lib --dependencies-only $CABALOPTS ShellCheck
+
+COPY build /usr/bin
+WORKDIR /scratch
+ENTRYPOINT ["/usr/bin/build"]

build/windows.x86_64/build

@@ -0,0 +1,19 @@
+#!/bin/sh
+cabal() {
+  wine /haskell/bin/cabal.exe  "$@"
+}
+
+set -xe
+{
+  tar xzv --strip-components=1
+  chmod +x striptests && ./striptests
+  mkdir "$TARGETNAME"
+  cabal update
+  ( IFS=';'; cabal build $CABALOPTS )
+  find dist*/ -name shellcheck.exe -type f -ls -exec mv {} "$TARGETNAME/" \;
+  ls -l "$TARGETNAME"
+  wine "/haskell/mingw/bin/strip.exe" -s "$TARGETNAME/shellcheck.exe"
+  ls -l "$TARGETNAME"
+  wine "$TARGETNAME/shellcheck.exe" --version
+} >&2
+tar czv "$TARGETNAME"

build/windows.x86_64/tag

@@ -0,0 +1 @@
+koalaman/scbuilder-windows-x86_64

nextnumber

@@ -6,7 +6,7 @@ then
   exit 1
 fi
 
-for i in 1 2
+for i in 1 2 3
 do
   last=$(grep -hv "^prop" ./**/*.hs | grep -Ewo "${i}[0-9]{3}" | sort -n | tail -n 1)
   echo "Next ${i}xxx: $((last+1))"

quickrun

@@ -2,4 +2,12 @@
 # quickrun runs ShellCheck in an interpreted mode.
 # This allows testing changes without recompiling.
 
-runghc -isrc -idist/build/autogen shellcheck.hs "$@"
+path=$(find . -type f -path './dist*/Paths_ShellCheck.hs' | sort | head -n 1)
+if [ -z "$path" ]
+then
+  echo >&2 "Unable to find Paths_ShellCheck.hs. Please 'cabal build' once."
+  exit 1
+fi
+path="${path%/*}"
+
+exec runghc -isrc -i"$path" shellcheck.hs "$@"

quicktest

@@ -3,8 +3,17 @@
 # This allows running tests without compiling, which can be faster.
 # 'cabal test' remains the source of truth.
 
+path=$(find . -type f -path './dist*/Paths_ShellCheck.hs' | sort | head -n 1)
+if [ -z "$path" ]
+then
+    echo >&2 "Unable to find Paths_ShellCheck.hs. Please 'cabal build' once."
+      exit 1
+fi
+path="${path%/*}"
+
+
 (
-var=$(echo 'main' | ghci test/shellcheck.hs 2>&1 | tee /dev/stderr)
+var=$(echo 'main' | ghci -isrc -i"$path" test/shellcheck.hs 2>&1 | tee /dev/stderr)
 if [[ $var == *ExitSuccess* ]]
 then
   exit 0

setgitversion

@@ -0,0 +1,11 @@
+#!/bin/sh -xe
+# This script hardcodes the `git describe` version as ShellCheck's version number.
+# This is done to allow shellcheck --version to differ from the cabal version when
+# building git snapshots.
+
+file="src/ShellCheck/Data.hs"
+test -e "$file"
+tmp=$(mktemp)
+version=$(git describe)
+sed -e "s/=.*VERSIONSTRING.*/= \"$version\" -- VERSIONSTRING, DO NOT SUBMIT/" "$file" > "$tmp"
+mv "$tmp" "$file"

shellcheck.1.md

@@ -112,6 +112,9 @@ not warn at all, as `ksh` supports decimals in arithmetic contexts.
     line (plus `/dev/null`). This option allows following any file the script
     may `source`.
 
+    This option may also be enabled using `external-sources=true` in
+    `.shellcheckrc`. This flag takes precedence.
+
 **FILES...**
 
 :   One or more script files to check, or "-" for standard input.
@@ -232,12 +235,22 @@ Valid keys are:
 **disable**
 :   Disables a comma separated list of error codes for the following command.
     The command can be a simple command like `echo foo`, or a compound command
-    like a function definition, subshell block or loop.
+    like a function definition, subshell block or loop. A range can be
+    be specified with a dash, e.g. `disable=SC3000-SC4000` to exclude 3xxx.
+    All warnings can be disabled with `disable=all`.
 
 **enable**
 :   Enable an optional check by name, as listed with **--list-optional**.
     Only file-wide `enable` directives are considered.
 
+**external-sources**
+:   Set to `true` in `.shellcheckrc` to always allow ShellCheck to open
+    arbitrary files from 'source' statements (the way most tools do).
+
+    This option defaults to `false` only due to ShellCheck's origin as a
+    remote service for checking untrusted scripts. It can safely be enabled
+    for normal development.
+
 **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
@@ -254,7 +267,7 @@ Valid keys are:
 **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'.
+    as a more targeted alternative to 'disable=SC2039'.
 
 # RC FILES
 
@@ -269,6 +282,12 @@ Here is an example `.shellcheckrc`:
     source-path=SCRIPTDIR
     source-path=/mnt/chroot
 
+    # Since 0.9.0, values can be quoted with '' or "" to allow spaces
+    source-path="My Documents/scripts"
+
+    # Allow opening any 'source'd file, even if not specified as input
+    external-sources=true
+
     # Turn on warnings for unquoted variables with safe values
     enable=quote-safe-variables
 
@@ -319,10 +338,32 @@ 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
+# KNOWN INCOMPATIBILITIES
 
-ShellCheck is developed and maintained by Vidar Holen, with assistance from a
-long list of wonderful contributors.
+(If nothing in this section makes sense, you are unlikely to be affected by it)
+
+To avoid confusing and misguided suggestions, ShellCheck requires function
+bodies to be either `{ brace groups; }` or `( subshells )`, and function names
+containing `[]*=!` are only recognized after a `function` keyword.
+
+The following unconventional function definitions are identical in Bash,
+but ShellCheck only recognizes the latter.
+
+    [x!=y] () [[ $1 ]]
+    function [x!=y] () { [[ $1 ]]; }
+
+Shells without the `function` keyword do not allow these characters in function
+names to begin with.  Function names containing `{}` are not supported at all.
+
+Further, if ShellCheck sees `[x!=y]` it will assume this is an invalid
+comparison. To invoke the above function, quote the command as in `'[x!=y]'`,
+or to retain the same globbing behavior, use `command [x!=y]`.
+
+ShellCheck imposes additional restrictions on the `[` command to help diagnose
+common invalid uses. While `[ $x= 1 ]` is defined in POSIX, ShellCheck will
+assume it was intended as the much more likely comparison `[ "$x" = 1 ]` and
+fail accordingly. For unconventional or dynamic uses of the `[` command, use
+`test` or `\[` instead.
 
 # REPORTING BUGS
 
@@ -330,9 +371,14 @@ Bugs and issues can be reported on GitHub:
 
 https://github.com/koalaman/shellcheck/issues
 
+# AUTHORS
+
+ShellCheck is developed and maintained by Vidar Holen, with assistance from a
+long list of wonderful contributors.
+
 # COPYRIGHT
 
-Copyright 2012-2019, Vidar Holen and contributors.
+Copyright 2012-2022, Vidar Holen and contributors.
 Licensed under the GNU General Public License version 3 or later,
 see https://gnu.org/licenses/gpl.html
 

shellcheck.hs

@@ -34,6 +34,8 @@ import qualified ShellCheck.Formatter.Quiet
 
 import           Control.Exception
 import           Control.Monad
+import           Control.Monad.IO.Class
+import           Control.Monad.Trans.Class
 import           Control.Monad.Except
 import           Data.Bits
 import           Data.Char
@@ -225,7 +227,7 @@ runFormatter sys format options files = do
     f :: Status -> FilePath -> IO Status
     f status file = do
         newStatus <- process file `catch` handler file
-        return $ status `mappend` newStatus
+        return $! status `mappend` newStatus
     handler :: FilePath -> IOException -> IO Status
     handler file e = reportFailure file (show e)
     reportFailure file str = do
@@ -234,7 +236,7 @@ runFormatter sys format options files = do
 
     process :: FilePath -> IO Status
     process filename = do
-        input <- siReadFile sys filename
+        input <- siReadFile sys Nothing filename
         either (reportFailure filename) check input
       where
         check contents = do
@@ -389,6 +391,7 @@ parseOption flag options =
             throwError SyntaxFailure
         return (Prelude.read num :: Integer)
 
+ioInterface :: Options -> [FilePath] -> IO (SystemInterface IO)
 ioInterface options files = do
     inputs <- mapM normalize files
     cache <- newIORef emptyCache
@@ -402,14 +405,14 @@ ioInterface options files = do
     emptyCache :: Map.Map FilePath String
     emptyCache = Map.empty
 
-    get cache inputs file = do
+    get cache inputs rcSuggestsExternal file = do
         map <- readIORef cache
         case Map.lookup file map of
             Just x  -> return $ Right x
-            Nothing -> fetch cache inputs file
+            Nothing -> fetch cache inputs rcSuggestsExternal file
 
-    fetch cache inputs file = do
-        ok <- allowable inputs file
+    fetch cache inputs rcSuggestsExternal file = do
+        ok <- allowable rcSuggestsExternal inputs file
         if ok
           then (do
             (contents, shouldCache) <- inputFile file
@@ -417,13 +420,16 @@ ioInterface options files = do
                 modifyIORef cache $ Map.insert file contents
             return $ Right contents
             ) `catch` handler
-          else return $ Left (file ++ " was not specified as input (see shellcheck -x).")
+          else
+            if rcSuggestsExternal == Just False
+            then return $ Left (file ++ " was not specified as input, and external files were disabled via directive.")
+            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
+    allowable rcSuggestsExternal inputs x =
+        if fromMaybe (externalSources options) rcSuggestsExternal
         then return True
         else do
             path <- normalize x
@@ -497,7 +503,7 @@ ioInterface options files = do
             b <- p x
             if b then pure (Just x) else acc
 
-    findSourceFile inputs sourcePathFlag currentScript sourcePathAnnotation original =
+    findSourceFile inputs sourcePathFlag currentScript rcSuggestsExternal sourcePathAnnotation original =
         if isAbsolute original
         then
             let (_, relative) = splitDrive original
@@ -506,8 +512,8 @@ ioInterface options files = do
             find original original
       where
         find filename deflt = do
-            sources <- findM ((allowable inputs) `andM` doesFileExist) $
-                        (adjustPath filename):(map (</> filename) $ map adjustPath $ sourcePathFlag ++ sourcePathAnnotation)
+            sources <- findM ((allowable rcSuggestsExternal inputs) `andM` doesFileExist) $
+                        (adjustPath filename):(map ((</> filename) . adjustPath) $ sourcePathFlag ++ sourcePathAnnotation)
             case sources of
                 Nothing -> return deflt
                 Just first -> return first

snap/snapcraft.yaml

@@ -16,12 +16,12 @@ description: |
     advanced user's otherwise working script to fail under future
     circumstances.
 
-  By default ShellCheck can only check non-hidden files under /home, to make 
+  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
@@ -31,6 +31,8 @@ apps:
   shellcheck:
     command: usr/bin/shellcheck
     plugs: [home, removable-media]
+    environment:
+      LANG: C.UTF-8
 
 parts:
   shellcheck:

src/ShellCheck/AST.hs

@@ -45,6 +45,7 @@ data InnerToken t =
     | Inner_TA_Variable String [t]
     | Inner_TA_Expansion [t]
     | Inner_TA_Sequence [t]
+    | Inner_TA_Parenthesis t
     | Inner_TA_Trinary t t t
     | Inner_TA_Unary String t
     | Inner_TC_And ConditionType String t t
@@ -141,15 +142,16 @@ data InnerToken t =
     | Inner_T_CoProcBody t
     | Inner_T_Include t
     | Inner_T_SourceCommand t t
-    | Inner_T_BatsTest t t
+    | Inner_T_BatsTest String t
     deriving (Show, Eq, Functor, Foldable, Traversable)
 
 data Annotation =
-    DisableComment Integer
+    DisableComment Integer Integer -- [from, to)
     | EnableComment String
     | SourceOverride String
     | ShellOverride String
     | SourcePath String
+    | ExternalSources Bool
     deriving (Show, Eq)
 data ConditionType = DoubleBracket | SingleBracket deriving (Show, Eq)
 
@@ -203,6 +205,7 @@ pattern T_Annotation id anns t = OuterToken id (Inner_T_Annotation anns t)
 pattern T_Arithmetic id c = OuterToken id (Inner_T_Arithmetic c)
 pattern T_Array id t = OuterToken id (Inner_T_Array t)
 pattern TA_Sequence id l = OuterToken id (Inner_TA_Sequence l)
+pattern TA_Parentesis id t = OuterToken id (Inner_TA_Parenthesis t)
 pattern T_Assignment id mode var indices value = OuterToken id (Inner_T_Assignment mode var indices value)
 pattern TA_Trinary id t1 t2 t3 = OuterToken id (Inner_TA_Trinary t1 t2 t3)
 pattern TA_Unary id op t1 = OuterToken id (Inner_TA_Unary op t1)
@@ -255,7 +258,7 @@ pattern T_Subshell id l = OuterToken id (Inner_T_Subshell l)
 pattern T_UntilExpression id c l = OuterToken id (Inner_T_UntilExpression c l)
 pattern T_WhileExpression id c l = OuterToken id (Inner_T_WhileExpression c l)
 
-{-# COMPLETE T_AND_IF, T_Bang, T_Case, TC_Empty, T_CLOBBER, T_DGREAT, T_DLESS, T_DLESSDASH, T_Do, T_DollarSingleQuoted, T_Done, T_DSEMI, T_Elif, T_Else, T_EOF, T_Esac, T_Fi, T_For, T_Glob, T_GREATAND, T_Greater, T_If, T_In, T_Lbrace, T_Less, T_LESSAND, T_LESSGREAT, T_Literal, T_Lparen, T_NEWLINE, T_OR_IF, T_ParamSubSpecialChar, T_Pipe, T_Rbrace, T_Rparen, T_Select, T_Semi, T_SingleQuoted, T_Then, T_UnparsedIndex, T_Until, T_While, TA_Assignment, TA_Binary, TA_Expansion, T_AndIf, T_Annotation, T_Arithmetic, T_Array, TA_Sequence, T_Assignment, TA_Trinary, TA_Unary, TA_Variable, T_Backgrounded, T_Backticked, T_Banged, T_BatsTest, T_BraceExpansion, T_BraceGroup, TC_And, T_CaseExpression, TC_Binary, TC_Group, TC_Nullary, T_Condition, T_CoProcBody, T_CoProc, TC_Or, TC_Unary, T_DollarArithmetic, T_DollarBraceCommandExpansion, T_DollarBraced, T_DollarBracket, T_DollarDoubleQuoted, T_DollarExpansion, T_DoubleQuoted, T_Extglob, T_FdRedirect, T_ForArithmetic, T_ForIn, T_Function, T_HereDoc, T_HereString, T_IfExpression, T_Include, T_IndexedElement, T_IoDuplicate, T_IoFile, T_NormalWord, T_OrIf, T_Pipeline, T_ProcSub, T_Redirecting, T_Script, T_SelectIn, T_SimpleCommand, T_SourceCommand, T_Subshell, T_UntilExpression, T_WhileExpression #-}
+{-# COMPLETE T_AND_IF, T_Bang, T_Case, TC_Empty, T_CLOBBER, T_DGREAT, T_DLESS, T_DLESSDASH, T_Do, T_DollarSingleQuoted, T_Done, T_DSEMI, T_Elif, T_Else, T_EOF, T_Esac, T_Fi, T_For, T_Glob, T_GREATAND, T_Greater, T_If, T_In, T_Lbrace, T_Less, T_LESSAND, T_LESSGREAT, T_Literal, T_Lparen, T_NEWLINE, T_OR_IF, T_ParamSubSpecialChar, T_Pipe, T_Rbrace, T_Rparen, T_Select, T_Semi, T_SingleQuoted, T_Then, T_UnparsedIndex, T_Until, T_While, TA_Assignment, TA_Binary, TA_Expansion, T_AndIf, T_Annotation, T_Arithmetic, T_Array, TA_Sequence, TA_Parentesis, T_Assignment, TA_Trinary, TA_Unary, TA_Variable, T_Backgrounded, T_Backticked, T_Banged, T_BatsTest, T_BraceExpansion, T_BraceGroup, TC_And, T_CaseExpression, TC_Binary, TC_Group, TC_Nullary, T_Condition, T_CoProcBody, T_CoProc, TC_Or, TC_Unary, T_DollarArithmetic, T_DollarBraceCommandExpansion, T_DollarBraced, T_DollarBracket, T_DollarDoubleQuoted, T_DollarExpansion, T_DoubleQuoted, T_Extglob, T_FdRedirect, T_ForArithmetic, T_ForIn, T_Function, T_HereDoc, T_HereString, T_IfExpression, T_Include, T_IndexedElement, T_IoDuplicate, T_IoFile, T_NormalWord, T_OrIf, T_Pipeline, T_ProcSub, T_Redirecting, T_Script, T_SelectIn, T_SimpleCommand, T_SourceCommand, T_Subshell, T_UntilExpression, T_WhileExpression #-}
 
 instance Eq Token where
     OuterToken _ a == OuterToken _ b = a == b

src/ShellCheck/ASTLib.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2021 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -17,9 +17,12 @@
     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.ASTLib where
 
 import ShellCheck.AST
+import ShellCheck.Prelude
+import ShellCheck.Regex
 
 import Control.Monad.Writer
 import Control.Monad
@@ -28,6 +31,12 @@ import Data.Functor
 import Data.Functor.Identity
 import Data.List
 import Data.Maybe
+import qualified Data.Map as Map
+import Numeric (showHex)
+
+import Test.QuickCheck
+
+arguments (T_SimpleCommand _ _ (cmd:args)) = args
 
 -- Is this a type of loop?
 isLoop t = case t of
@@ -51,10 +60,28 @@ willSplit x =
     T_NormalWord _ l -> any willSplit l
     _ -> False
 
-isGlob T_Extglob {} = True
-isGlob T_Glob {} = True
-isGlob (T_NormalWord _ l) = any isGlob l
-isGlob _ = False
+isGlob t = case t of
+    T_Extglob {} -> True
+    T_Glob {} -> True
+    T_NormalWord _ l -> any isGlob l || hasSplitRange l
+    _ -> False
+  where
+    -- foo[x${var}y] gets parsed as foo,[,x,$var,y],
+    -- so check if there's such an interval
+    hasSplitRange l =
+        let afterBracket = dropWhile (not . isHalfOpenRange) l
+        in any isClosingRange afterBracket
+
+    isHalfOpenRange t =
+        case t of
+            T_Literal _ "[" -> True
+            _ -> False
+
+    isClosingRange t =
+        case t of
+            T_Literal _ str -> ']' `elem` str
+            _ -> False
+
 
 -- Is this shell word a constant?
 isConstant token =
@@ -112,7 +139,7 @@ getFlagsUntil stopCondition (T_SimpleCommand _ _ (_:args)) =
     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)"
+getFlagsUntil _ _ = error $ pleaseReport "getFlags on non-command"
 
 -- Get all flags in a GNU way, up until --
 getAllFlags :: Token -> [(Token, String)]
@@ -134,26 +161,141 @@ 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)"
+-- getGnuOpts "erd:u:" will parse a list of arguments tokens like `read`
+--     -re -d : -u 3 bar
+-- into
+--     Just [("r", (-re, -re)), ("e", (-re, -re)), ("d", (-d,:)), ("u", (-u,3)), ("", (bar,bar))]
+--
+-- Each string flag maps to a tuple of (flag, argument), where argument=flag if it
+-- doesn't take a specific one.
+--
+-- Any unrecognized flag will result in Nothing. The exception is if arbitraryLongOpts
+-- is set, in which case --anything will map to "anything".
+getGnuOpts :: String -> [Token] -> Maybe [(String, (Token, Token))]
+getGnuOpts str args = getOpts (True, False) str [] args
+
+-- As above, except the first non-arg string will treat the rest as arguments
+getBsdOpts :: String -> [Token] -> Maybe [(String, (Token, Token))]
+getBsdOpts str args = getOpts (False, False) str [] args
+
+-- Tests for this are in Commands.hs where it's more frequently used
+getOpts ::
+    -- Behavioral config: gnu style, allow arbitrary long options
+    (Bool, Bool)
+    -- A getopts style string
+    -> String
+    -- List of long options and whether they take arguments
+    -> [(String, Bool)]
+    -- List of arguments (excluding command)
+    -> [Token]
+    -- List of flags to tuple of (optionToken, valueToken)
+    -> Maybe [(String, (Token, Token))]
+
+getOpts (gnu, arbitraryLongOpts) string longopts args = process args
+  where
+    flagList (c:':':rest) = ([c], True) : flagList rest
+    flagList (c:rest)     = ([c], False) : flagList rest
+    flagList []           = longopts
+    flagMap = Map.fromList $ ("", False) : flagList string
+
+    process [] = return []
+    process (token:rest) = do
+        case getLiteralStringDef "\0" token of
+            "--" -> return $ listToArgs rest
+            '-':'-':word -> do
+                let (name, arg) = span (/= '=') word
+                needsArg <-
+                    if arbitraryLongOpts
+                    then return $ Map.findWithDefault False name flagMap
+                    else Map.lookup name flagMap
+
+                if needsArg && null arg
+                  then
+                    case rest of
+                        (arg:rest2) -> do
+                            more <- process rest2
+                            return $ (name, (token, arg)) : more
+                        _ -> fail "Missing arg"
+                  else do
+                    more <- process rest
+                    -- Consider splitting up token to get arg
+                    return $ (name, (token, token)) : more
+            '-':opts -> shortToOpts opts token rest
+            arg ->
+                if gnu
+                then do
+                    more <- process rest
+                    return $ ("", (token, token)):more
+                else return $ listToArgs (token:rest)
+
+    shortToOpts opts token args =
+        case opts of
+            c:rest -> do
+                needsArg <- Map.lookup [c] flagMap
+                case () of
+                    _ | needsArg && null rest -> do
+                        (next:restArgs) <- return args
+                        more <- process restArgs
+                        return $ ([c], (token, next)):more
+                    _ | needsArg -> do
+                        more <- process args
+                        return $ ([c], (token, token)):more
+                    _ -> do
+                        more <- shortToOpts rest token args
+                        return $ ([c], (token, token)):more
+            [] -> process args
+
+    listToArgs = map (\x -> ("", (x, x)))
+
+
+-- Generic getOpts that doesn't rely on a format string, but may also be inaccurate.
+-- This provides a best guess interpretation instead of failing when new options are added.
+--
+--    "--" is treated as end of arguments
+--    "--anything[=foo]" is treated as a long option without argument
+--    "-any" is treated as -a -n -y, with the next arg as an option to -y unless it starts with -
+--    anything else is an argument
+getGenericOpts :: [Token] -> [(String, (Token, Token))]
+getGenericOpts = process
+  where
+    process (token:rest) =
+        case getLiteralStringDef "\0" token of
+            "--" -> map (\c -> ("", (c,c))) rest
+            '-':'-':word -> (takeWhile (`notElem` "\0=") word, (token, token)) : process rest
+            '-':optString ->
+                let opts = takeWhile (/= '\0') optString
+                in
+                    case rest of
+                        next:_ | "-" `isPrefixOf` getLiteralStringDef "\0" next  ->
+                            map (\c -> ([c], (token, token))) opts ++ process rest
+                        next:remainder ->
+                            case reverse opts of
+                                last:initial ->
+                                    map (\c -> ([c], (token, token))) (reverse initial)
+                                        ++ [([last], (token, next))]
+                                        ++ process remainder
+                                [] -> process remainder
+                        [] -> map (\c -> ([c], (token, token))) opts
+            _ -> ("", (token, token)) : process rest
+    process [] = []
+
 
 -- Is this an expansion of multiple items of an array?
-isArrayExpansion t@(T_DollarBraced _ _ _) =
-    let string = bracedString t in
+isArrayExpansion (T_DollarBraced _ _ l) =
+    let string = concat $ oversimplify l 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
+mayBecomeMultipleArgs t = willBecomeMultipleArgs t || f False 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
+    f quoted (T_DollarBraced _ _ l) =
+        let string = concat $ oversimplify l in
+            not quoted || "!" `isPrefixOf` string
+    f quoted (T_DoubleQuoted _ parts) = any (f True) parts
+    f quoted (T_NormalWord _ parts) = any (f quoted) parts
+    f _ _ = False
 
 -- Is it certain that this word will becomes multiple words?
 willBecomeMultipleArgs t = willConcatInAssignment t || f t
@@ -161,7 +303,6 @@ willBecomeMultipleArgs t = willConcatInAssignment t || f t
     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
 
@@ -193,6 +334,12 @@ getUnquotedLiteral (T_NormalWord _ list) =
     str _ = Nothing
 getUnquotedLiteral _ = Nothing
 
+isQuotes t =
+    case t of
+        T_DoubleQuoted {} -> True
+        T_SingleQuoted {} -> True
+        _ -> False
+
 -- 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
@@ -211,8 +358,11 @@ getTrailingUnquotedLiteral t =
 getLeadingUnquotedString :: Token -> Maybe String
 getLeadingUnquotedString t =
     case t of
-        T_NormalWord _ ((T_Literal _ s) : _) -> return s
+        T_NormalWord _ ((T_Literal _ s) : rest) -> return $ s ++ from rest
         _ -> Nothing
+  where
+    from ((T_Literal _ s):rest) = s ++ from rest
+    from _ = ""
 
 -- Maybe get the literal string of this token and any globs in it.
 getGlobOrLiteralString = getLiteralStringExt f
@@ -220,6 +370,21 @@ getGlobOrLiteralString = getLiteralStringExt f
     f (T_Glob _ str) = return str
     f _ = Nothing
 
+
+prop_getLiteralString1 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\x01") == Just "\1"
+prop_getLiteralString2 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\xyz") == Just "\\xyz"
+prop_getLiteralString3 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\x1") == Just "\x1"
+prop_getLiteralString4 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\x1y") == Just "\x1y"
+prop_getLiteralString5 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\xy") == Just "\\xy"
+prop_getLiteralString6 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\x") == Just "\\x"
+prop_getLiteralString7 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\1x") == Just "\1x"
+prop_getLiteralString8 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\12x") == Just "\o12x"
+prop_getLiteralString9 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\123x") == Just "\o123x"
+prop_getLiteralString10 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\1234") == Just "\o123\&4"
+prop_getLiteralString11 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\1") == Just "\1"
+prop_getLiteralString12 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\12") == Just "\o12"
+prop_getLiteralString13 = getLiteralString (T_DollarSingleQuoted (Id 0) "\\123") == Just "\o123"
+
 -- Maybe get the literal value of a token, using a custom function
 -- to map unrecognized Tokens into strings.
 getLiteralStringExt :: Monad m => (Token -> m String) -> Token -> m String
@@ -252,14 +417,15 @@ getLiteralStringExt more = g
             '\\' -> '\\' : rest
             'x' ->
                 case cs of
-                    (x:y:more) ->
-                        if isHexDigit x && isHexDigit y
-                        then chr (16*(digitToInt x) + (digitToInt y)) : rest
-                        else '\\':c:rest
+                    (x:y:more) | isHexDigit x && isHexDigit y ->
+                        chr (16*(digitToInt x) + (digitToInt y)) : decodeEscapes more
+                    (x:more) | isHexDigit x ->
+                        chr (digitToInt x) : decodeEscapes more
+                    more -> '\\' : 'x' : decodeEscapes more
             _ | isOctDigit c ->
-                let digits = take 3 $ takeWhile isOctDigit (c:cs)
-                    num = parseOct digits
-                in (if num < 256 then chr num else '?') : rest
+                let (digits, more) = spanMax isOctDigit 3 (c:cs)
+                    num = (parseOct digits) `mod` 256
+                in (chr num) : decodeEscapes more
             _ -> '\\' : c : rest
       where
         rest = decodeEscapes cs
@@ -267,12 +433,48 @@ getLiteralStringExt more = g
           where
             f n "" = n
             f n (c:rest) = f (n * 8 + digitToInt c) rest
+        spanMax f n list =
+            let (first, second) = span f list
+                (prefix, suffix) = splitAt n first
+            in
+                (prefix, suffix ++ second)
     decodeEscapes (c:cs) = c : decodeEscapes cs
     decodeEscapes [] = []
 
 -- Is this token a string literal?
 isLiteral t = isJust $ getLiteralString t
 
+-- Escape user data for messages.
+-- Messages generally avoid repeating user data, but sometimes it's helpful.
+e4m = escapeForMessage
+escapeForMessage :: String -> String
+escapeForMessage str = concatMap f str
+  where
+    f '\\' = "\\\\"
+    f '\n' = "\\n"
+    f '\r' = "\\r"
+    f '\t' = "\\t"
+    f '\x1B' = "\\e"
+    f c =
+        if shouldEscape c
+        then
+            if ord c < 256
+            then "\\x" ++ (pad0 2 $ toHex c)
+            else "\\U" ++ (pad0 4 $ toHex c)
+        else [c]
+
+    shouldEscape c =
+        (not $ isPrint c)
+        || (not (isAscii c) && not (isLetter c))
+
+    pad0 :: Int -> String -> String
+    pad0 n s =
+        let l = length s in
+            if l < n
+            then (replicate (n-l) '0') ++ s
+            else s
+    toHex :: Char -> String
+    toHex c = map toUpper $ showHex (ord c) ""
 
 -- Turn a NormalWord like foo="bar $baz" into a series of constituent elements like [foo=,bar ,$baz]
 getWordParts (T_NormalWord _ l)   = concatMap getWordParts l
@@ -301,7 +503,7 @@ getCommand t =
 
 -- Maybe get the command name string of a token representing a command
 getCommandName :: Token -> Maybe String
-getCommandName = fst . getCommandNameAndToken
+getCommandName = fst . getCommandNameAndToken False
 
 -- Maybe get the name+arguments of a command.
 getCommandArgv t = do
@@ -311,20 +513,38 @@ getCommandArgv t = do
 -- 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
+getCommandTokenOrThis = snd . getCommandNameAndToken False
 
-getCommandNameAndToken :: Token -> (Maybe String, Token)
-getCommandNameAndToken t = fromMaybe (Nothing, t) $ do
-    (T_SimpleCommand _ _ (w:rest)) <- getCommand t
+-- Given a command, get the string and token that represents the command name.
+-- If direct, return the actual command (e.g. exec in 'exec ls')
+-- If not, return the logical command (e.g. 'ls' in 'exec ls')
+
+getCommandNameAndToken :: Bool -> Token -> (Maybe String, Token)
+getCommandNameAndToken direct t = fromMaybe (Nothing, t) $ do
+    cmd@(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)
-
+    return $ fromMaybe (Just s, w) $ do
+        guard $ not direct
+        actual <- getEffectiveCommandToken s cmd rest
+        return (getLiteralString actual, actual)
+  where
+    getEffectiveCommandToken str cmd args =
+        let
+            firstArg = do
+                arg <- listToMaybe args
+                guard . not $ isFlag arg
+                return arg
+        in
+            case str of
+                "busybox" -> firstArg
+                "builtin" -> firstArg
+                "command" -> firstArg
+                "run" -> firstArg -- Used by bats
+                "exec" -> do
+                    opts <- getBsdOpts "cla:" args
+                    (_, (t, _)) <- find (null . fst) opts
+                    return t
+                _ -> fail ""
 
 -- If a command substitution is a single command, get its name.
 --  $(date +%s) = Just "date"
@@ -341,8 +561,8 @@ getCommandNameFromExpansion t =
 
 -- Get the basename of a token representing a command
 getCommandBasename = fmap basename . getCommandName
-  where
-    basename = reverse . takeWhile (/= '/') . reverse
+
+basename = reverse . takeWhile (/= '/') . reverse
 
 isAssignment t =
     case t of
@@ -400,10 +620,10 @@ getAssociativeArrays t =
     f t@T_SimpleCommand {} = sequence_ $ do
         name <- getCommandName t
         let assocNames = ["declare","local","typeset"]
-        guard $ elem name assocNames
+        guard $ name `elem` assocNames
         let flags = getAllFlags t
-        guard $ elem "A" $ map snd flags
-        let args = map fst . filter ((==) "" . snd) $ flags
+        guard $ "A" `elem` map snd flags
+        let args = [arg | (arg, "") <- flags]
         let names = mapMaybe (getLiteralStringExt nameAssignments) args
         return $ tell names
     f _ = return ()
@@ -421,38 +641,36 @@ data PseudoGlob = PGAny | PGMany | PGChar Char
 
 -- 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]
+wordToPseudoGlob :: Token -> [PseudoGlob]
+wordToPseudoGlob = fromMaybe [PGMany] . wordToPseudoGlob' False
 
 -- Turn a word into a PG pattern, but only if we can preserve
 -- exact semantics.
 wordToExactPseudoGlob :: Token -> Maybe [PseudoGlob]
-wordToExactPseudoGlob word =
-    simplifyPseudoGlob . concat <$> mapM f (getWordParts word)
+wordToExactPseudoGlob = wordToPseudoGlob' True
+
+wordToPseudoGlob' :: Bool -> Token -> Maybe [PseudoGlob]
+wordToPseudoGlob' exact word =
+    simplifyPseudoGlob <$> toGlob word
   where
+    toGlob :: Token -> Maybe [PseudoGlob]
+    toGlob word =
+        case word of
+            T_NormalWord _ (T_Literal _ ('~':str):rest) -> do
+                guard $ not exact
+                let this = (PGMany : (map PGChar $ dropWhile (/= '/') str))
+                tail <- concat <$> (mapM f $ concatMap getWordParts rest)
+                return $ this ++ tail
+            _ -> concat <$> (mapM f $ getWordParts word)
+
     f x = case x of
-        T_Literal _ s -> return $ map PGChar s
+        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"
+        T_Glob _ "?"       -> return [PGAny]
+        T_Glob _ "*"       -> return [PGMany]
+        T_Glob _ ('[':_) | not exact -> return [PGAny]
+        _ -> if exact then fail "" else return [PGMany]
+
 
 -- Reorder a PseudoGlob for more efficient matching, e.g.
 -- f?*?**g -> f??*g
@@ -502,8 +720,7 @@ pseudoGlobIsSuperSetof = matchable
     matchable (PGMany : rest) [] = matchable rest []
     matchable _ _ = False
 
-wordsCanBeEqual x y = fromMaybe True $
-    liftM2 pseudoGlobsCanOverlap (wordToPseudoGlob x) (wordToPseudoGlob y)
+wordsCanBeEqual x y = pseudoGlobsCanOverlap (wordToPseudoGlob x) (wordToPseudoGlob y)
 
 -- Is this an expansion that can be quoted,
 -- e.g. $(foo) `foo` $foo (but not {foo,})?
@@ -517,6 +734,11 @@ isCommandSubstitution t = case t of
     T_Backticked {} -> True
     _ -> False
 
+-- Is this an expansion that results in a simple string?
+isStringExpansion t = isCommandSubstitution t || case t of
+    T_DollarArithmetic {} -> True
+    T_DollarBraced {} -> not (isArrayExpansion t)
+    _ -> False
 
 -- Is this a T_Annotation that ignores a specific code?
 isAnnotationIgnoringCode code t =
@@ -524,5 +746,162 @@ isAnnotationIgnoringCode code t =
         T_Annotation _ anns _ -> any hasNum anns
         _ -> False
   where
-    hasNum (DisableComment ts) = code == ts
+    hasNum (DisableComment from to) = code >= from && code < to
     hasNum _                   = False
+
+prop_executableFromShebang1 = executableFromShebang "/bin/sh" == "sh"
+prop_executableFromShebang2 = executableFromShebang "/bin/bash" == "bash"
+prop_executableFromShebang3 = executableFromShebang "/usr/bin/env ksh" == "ksh"
+prop_executableFromShebang4 = executableFromShebang "/usr/bin/env -S foo=bar bash -x" == "bash"
+prop_executableFromShebang5 = executableFromShebang "/usr/bin/env --split-string=bash -x" == "bash"
+prop_executableFromShebang6 = executableFromShebang "/usr/bin/env --split-string=foo=bar bash -x" == "bash"
+prop_executableFromShebang7 = executableFromShebang "/usr/bin/env --split-string bash -x" == "bash"
+prop_executableFromShebang8 = executableFromShebang "/usr/bin/env --split-string foo=bar bash -x" == "bash"
+prop_executableFromShebang9 = executableFromShebang "/usr/bin/env foo=bar dash" == "dash"
+prop_executableFromShebang10 = executableFromShebang "/bin/busybox sh" == "ash"
+prop_executableFromShebang11 = executableFromShebang "/bin/busybox ash" == "ash"
+
+-- Get the shell executable from a string like '/usr/bin/env bash'
+executableFromShebang :: String -> String
+executableFromShebang = shellFor
+  where
+    re = mkRegex "/env +(-S|--split-string=?)? *(.*)"
+    shellFor s | s `matches` re =
+        case matchRegex re s of
+            Just [flag, shell] -> fromEnvArgs (words shell)
+            _ -> ""
+    shellFor sb =
+        case words sb of
+            [] -> ""
+            [x] -> basename x
+            (first:second:args) | basename first == "busybox" ->
+                case basename second of
+                   "sh" -> "ash" -- busybox sh is ash
+                   x -> x
+            (first:args) | basename first == "env" ->
+                fromEnvArgs args
+            (first:_) -> basename first
+
+    fromEnvArgs args = fromMaybe "" $ find (notElem '=') $ skipFlags args
+    basename s = reverse . takeWhile (/= '/') . reverse $ s
+    skipFlags = dropWhile ("-" `isPrefixOf`)
+
+
+-- Determining if a name is a variable
+isVariableStartChar x = x == '_' || isAsciiLower x || isAsciiUpper x
+isVariableChar x = isVariableStartChar x || isDigit x
+isSpecialVariableChar = (`elem` "*@#?-$!")
+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
+
+
+-- 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_getBracedReference11b = 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) | c `elem` "!#" = rest
+    dropPrefix cs = cs
+    takeName s = do
+        let name = takeWhile isVariableChar s
+        guard . not $ null name
+        return name
+    getSpecial (c:_) | isSpecialVariableChar c = return [c]
+    getSpecial _ = fail "empty or not special"
+
+    nameExpansion ('!':next:rest) = do -- e.g. ${!foo*bar*}
+        guard $ isVariableChar next -- e.g. ${!@}
+        first <- find (not . isVariableChar) rest
+        guard $ first `elem` "*?@"
+        return ""
+    nameExpansion _ = Nothing
+
+-- Get the variable modifier like /a/b in ${var/a/b}
+prop_getBracedModifier1 = getBracedModifier "foo:bar:baz" == ":bar:baz"
+prop_getBracedModifier2 = getBracedModifier "!var:-foo" == ":-foo"
+prop_getBracedModifier3 = getBracedModifier "foo[bar]" == "[bar]"
+prop_getBracedModifier4 = getBracedModifier "foo[@]@Q" == "[@]@Q"
+prop_getBracedModifier5 = getBracedModifier "@@Q" == "@Q"
+getBracedModifier s = headOrDefault "" $ 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]
+
+-- Get the variables from indices like ["x", "y"] in ${var[x+y+1]}
+prop_getIndexReferences1 = getIndexReferences "var[x+y+1]" == ["x", "y"]
+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 "^(\\[.+\\])? *:([^-=?+].*)"
+
+
+-- Returns whether a token is a parameter expansion without any modifiers.
+-- True for $var ${var} $1 $#
+-- False for ${#var} ${var[x]} ${var:-0}
+isUnmodifiedParameterExpansion t =
+    case t of
+        T_DollarBraced _ False _ -> True
+        T_DollarBraced _ _ list ->
+            let str = concat $ oversimplify list
+            in getBracedReference str == str
+        _ -> 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
+
+isClosingFileOp op =
+    case op of
+        T_IoDuplicate _ (T_GREATAND _) "-" -> True
+        T_IoDuplicate _ (T_LESSAND  _) "-" -> True
+        _                                  -> False
+
+getEnableDirectives root =
+    case root of
+        T_Annotation _ list _ -> [s | EnableComment s <- list]
+        _ -> []
+
+return []
+runTests = $quickCheckAll

src/ShellCheck/Analyzer.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2022 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -25,6 +25,7 @@ import ShellCheck.Interface
 import Data.List
 import Data.Monoid
 import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.ControlFlow
 import qualified ShellCheck.Checks.Custom
 import qualified ShellCheck.Checks.ShellSupport
 
@@ -34,19 +35,21 @@ analyzeScript :: AnalysisSpec -> AnalysisResult
 analyzeScript spec = newAnalysisResult {
     arComments =
         filterByAnnotation spec params . nub $
-            runAnalytics spec
-            ++ runChecker params (checkers spec params)
+            runChecker params (checkers spec params)
 }
   where
     params = makeParameters spec
 
 checkers spec params = mconcat $ map ($ params) [
+    ShellCheck.Analytics.checker spec,
     ShellCheck.Checks.Commands.checker spec,
+    ShellCheck.Checks.ControlFlow.checker spec,
     ShellCheck.Checks.Custom.checker,
     ShellCheck.Checks.ShellSupport.checker
     ]
 
 optionalChecks = mconcat $ [
     ShellCheck.Analytics.optionalChecks,
-    ShellCheck.Checks.Commands.optionalChecks
+    ShellCheck.Checks.Commands.optionalChecks,
+    ShellCheck.Checks.ControlFlow.optionalChecks
     ]

src/ShellCheck/AnalyzerLib.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2022 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -23,13 +23,16 @@ module ShellCheck.AnalyzerLib where
 
 import ShellCheck.AST
 import ShellCheck.ASTLib
+import qualified ShellCheck.CFGAnalysis as CF
 import ShellCheck.Data
 import ShellCheck.Interface
 import ShellCheck.Parser
+import ShellCheck.Prelude
 import ShellCheck.Regex
 
 import Control.Arrow (first)
 import Control.DeepSeq
+import Control.Monad
 import Control.Monad.Identity
 import Control.Monad.RWS
 import Control.Monad.State
@@ -79,10 +82,16 @@ 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 the 'inherit_errexit' option set/default.
+    hasInheritErrexit  :: Bool,
     -- Whether this script has 'set -e' anywhere.
     hasSetE            :: Bool,
+    -- Whether this script has 'set -o pipefail' anywhere.
+    hasPipefail        :: Bool,
     -- A linear (bad) analysis of data flow
     variableFlow       :: [StackData],
+    -- A map from Id to Token
+    idMap              :: Map.Map Id Token,
     -- A map from Id to parent Token
     parentMap          :: Map.Map Id Token,
     -- The shell type, such as Bash or Ksh
@@ -92,7 +101,9 @@ data Parameters = Parameters {
     -- The root node of the AST
     rootNode           :: Token,
     -- map from token id to start and end position
-    tokenPositions     :: Map.Map Id (Position, Position)
+    tokenPositions     :: Map.Map Id (Position, Position),
+    -- Result from Control Flow Graph analysis (including data flow analysis)
+    cfgAnalysis :: CF.CFGAnalysis
     } deriving (Show)
 
 -- TODO: Cache results of common AST ops here
@@ -142,7 +153,7 @@ producesComments c s = do
         prRoot pr
         let spec = defaultSpec pr
         let params = makeParameters spec
-        return . not . null $ runChecker params c
+        return . not . null $ filterByAnnotation spec params $ runChecker params c
 
 makeComment :: Severity -> Id -> Code -> String -> TokenComment
 makeComment severity id code note =
@@ -163,8 +174,12 @@ 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
 
+errWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
+errWithFix  = addCommentWithFix ErrorC
 warnWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
 warnWithFix  = addCommentWithFix WarningC
+infoWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
+infoWithFix = addCommentWithFix InfoC
 styleWithFix :: MonadWriter [TokenComment] m => Id -> Code -> String -> Fix -> m ()
 styleWithFix = addCommentWithFix StyleC
 
@@ -176,28 +191,47 @@ 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
+            -- If fix is empty, pretend it wasn't there.
+            tcFix = if null (fixReplacements fix) then Nothing else Just fix
         }
-    in withFix `deepseq` withFix
+    in force withFix
 
-makeParameters spec =
-    let params = Parameters {
+makeParameters spec = params
+  where
+    params = Parameters {
         rootNode = root,
         shellType = fromMaybe (determineShell (asFallbackShell spec) root) $ asShellType spec,
         hasSetE = containsSetE root,
         hasLastpipe =
             case shellType params of
-                Bash -> containsLastpipe root
+                Bash -> isOptionSet "lastpipe" root
                 Dash -> False
                 Sh   -> False
                 Ksh  -> True,
-
+        hasInheritErrexit =
+            case shellType params of
+                Bash -> isOptionSet "inherit_errexit" root
+                Dash -> True
+                Sh   -> True
+                Ksh  -> False,
+        hasPipefail =
+            case shellType params of
+                Bash -> isOptionSet "pipefail" root
+                Dash -> True
+                Sh   -> True
+                Ksh  -> isOptionSet "pipefail" root,
         shellTypeSpecified = isJust (asShellType spec) || isJust (asFallbackShell spec),
+        idMap = getTokenMap root,
         parentMap = getParentTree root,
         variableFlow = getVariableFlow params root,
-        tokenPositions = asTokenPositions spec
-    } in params
-  where root = asScript spec
+        tokenPositions = asTokenPositions spec,
+        cfgAnalysis = CF.analyzeControlFlow cfParams root
+    }
+    cfParams = CF.CFGParameters {
+        CF.cfLastpipe = hasLastpipe params,
+        CF.cfPipefail = hasPipefail params
+    }
+    root = asScript spec
 
 
 -- Does this script mention 'set -e' anywhere?
@@ -214,18 +248,30 @@ containsSetE root = isNothing $ doAnalysis (guard . not . isSetE) root
             _ -> False
     re = mkRegex "[[:space:]]-[^-]*e"
 
--- Does this script mention 'shopt -s lastpipe' anywhere?
--- Also used as a hack.
-containsLastpipe root =
+
+containsSetOption opt root = isNothing $ doAnalysis (guard . not . isPipefail) root
+  where
+    isPipefail t =
+        case t of
+            T_SimpleCommand {}  ->
+                t `isUnqualifiedCommand` "set" &&
+                    (opt `elem` oversimplify t ||
+                        "o" `elem` map snd (getAllFlags t))
+            _ -> False
+
+containsShopt shopt root =
         isNothing $ doAnalysis (guard . not . isShoptLastPipe) root
     where
         isShoptLastPipe t =
             case t of
                 T_SimpleCommand {}  ->
                     t `isUnqualifiedCommand` "shopt" &&
-                        ("lastpipe" `elem` oversimplify t)
+                        (shopt `elem` oversimplify t)
                 _ -> False
 
+-- Does this script mention 'shopt -s $opt' or 'set -o $opt' anywhere?
+isOptionSet opt root = containsShopt opt root || containsSetOption opt root
+
 
 prop_determineShell0 = determineShellTest "#!/bin/sh" == Sh
 prop_determineShell1 = determineShellTest "#!/usr/bin/env ksh" == Ksh
@@ -236,6 +282,10 @@ 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
+prop_determineShell9 = determineShellTest "#!/bin/env -S dash -x" == Dash
+prop_determineShell10 = determineShellTest "#!/bin/env --split-string= dash -x" == Dash
+prop_determineShell11 = determineShellTest "#!/bin/busybox sh" == Dash -- busybox sh is a specific shell, not posix sh
+prop_determineShell12 = determineShellTest "#!/bin/busybox ash" == Dash
 
 determineShellTest = determineShellTest' Nothing
 determineShellTest' fallbackShell = determineShell fallbackShell . fromJust . prRoot . pScript
@@ -249,22 +299,11 @@ determineShell fallbackShell t = fromMaybe Bash $
         headOrDefault (fromShebang s) [s | ShellOverride s <- annotations]
     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 = headOrDefault "" (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)
+    snd $ execState (doStackAnalysis pre post t) ([], Map.empty)
   where
     pre t = modify (first ((:) t))
     post t = do
@@ -292,16 +331,16 @@ isStrictlyQuoteFree = isQuoteFreeNode True
 isQuoteFree = isQuoteFreeNode False
 
 
-isQuoteFreeNode strict tree t =
-    (isQuoteFreeElement t == Just True) ||
-        headOrDefault False (mapMaybe isQuoteFreeContext (drop 1 $ getPath tree t))
+isQuoteFreeNode strict shell tree t =
+    isQuoteFreeElement t ||
+        (fromMaybe False $ msum $ map isQuoteFreeContext $ drop 1 $ getPath tree t)
   where
     -- Is this node self-quoting in itself?
     isQuoteFreeElement t =
         case t of
-            T_Assignment {} -> return True
-            T_FdRedirect {} -> return True
-            _               -> Nothing
+            T_Assignment {} -> assignmentIsQuoting t
+            T_FdRedirect {} -> True
+            _               -> False
 
     -- Are any subnodes inherently self-quoting?
     isQuoteFreeContext t =
@@ -311,7 +350,7 @@ isQuoteFreeNode strict tree t =
             TC_Binary _ DoubleBracket _ _ _ -> return True
             TA_Sequence {}                  -> return True
             T_Arithmetic {}                 -> return True
-            T_Assignment {}                 -> return True
+            T_Assignment {}                 -> return $ assignmentIsQuoting t
             T_Redirecting {}                -> return False
             T_DoubleQuoted _ _              -> return True
             T_DollarDoubleQuoted _ _        -> return True
@@ -323,6 +362,18 @@ isQuoteFreeNode strict tree t =
             T_SelectIn {}                   -> return (not strict)
             _                               -> Nothing
 
+    -- Check whether this assignment is self-quoting due to being a recognized
+    -- assignment passed to a Declaration Utility. This will soon be required
+    -- by POSIX: https://austingroupbugs.net/view.php?id=351
+    assignmentIsQuoting t = shellParsesParamsAsAssignments || not (isAssignmentParamToCommand t)
+    shellParsesParamsAsAssignments = shell /= Sh
+
+    -- Is this assignment a parameter to a command like export/typeset/etc?
+    isAssignmentParamToCommand (T_Assignment id _ _ _ _) =
+        case Map.lookup id tree of
+            Just (T_SimpleCommand _ _ (_:args)) -> id `elem` (map getId args)
+            _ -> False
+
 -- 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
@@ -354,8 +405,8 @@ getClosestCommand tree t =
 
 -- Like above, if koala_man knew Haskell when starting this project.
 getClosestCommandM t = do
-    tree <- asks parentMap
-    return $ getClosestCommand tree t
+    params <- ask
+    return $ getClosestCommand (parentMap params) 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)
@@ -364,21 +415,15 @@ usedAsCommandName tree token = go (getId token) (tail $ getPath tree token)
         | 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 currentId (t@(T_SimpleCommand _ _ (word:_)):_) =
+        getId word == currentId || getId (getCommandTokenOrThis t) == currentId
     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
+    params <- ask
+    return $ getPath (parentMap params) t
 
 isParentOf tree parent child =
     elem (getId parent) . map getId $ getPath tree child
@@ -388,14 +433,13 @@ 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
+findFirst p = foldr go Nothing
+  where
+    go x acc =
+      case p x of
+        Just True  -> return x
+        Just False -> Nothing
+        Nothing    -> acc
 
 -- Check whether a word is entirely output from a single command
 tokenIsJustCommandOutput t = case t of
@@ -410,8 +454,7 @@ tokenIsJustCommandOutput t = case t of
 
 -- TODO: Replace this with a proper Control Flow Graph
 getVariableFlow params t =
-    let (_, stack) = runState (doStackAnalysis startScope endScope t) []
-    in reverse stack
+    reverse $ execState (doStackAnalysis startScope endScope t) []
   where
     startScope t =
         let scopeType = leadType params t
@@ -462,30 +505,22 @@ leadType params t =
 
     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
+        return $ case list of
+            _:_:_ -> not (hasLastpipe params) || getId (last list) /= getId t
+            _ -> False
 
 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
+            [(x, x, name, dataTypeFrom DataString w) | x@(T_Assignment id _ name _ w) <- vars]
+        T_SimpleCommand {} ->
+            getModifiedVariableCommand t
 
-        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
+        TA_Unary _ op v@(TA_Variable _ name _) | "--" `isInfixOf` op || "++" `isInfixOf` op ->
+            [(t, v, name, DataString SourceInteger)]
+        TA_Assignment _ op (TA_Variable _ name _) rhs -> do
             guard $ op `elem` ["=", "*=", "/=", "%=", "+=", "-=", "<<=", ">>=", "&=", "^=", "|="]
-            return (t, t, name, DataString $ SourceFrom [rhs])
+            return (t, t, name, DataString SourceInteger)
 
         T_BatsTest {} -> [
             (t, t, "lines", DataArray SourceExternal),
@@ -496,25 +531,23 @@ getModifiedVariables t =
         -- 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
+            str <- getVariableForTestDashV token
             return (t, token, str, DataString SourceChecked)
 
+        TC_Unary _ _ "-n" token -> markAsChecked t token
+        TC_Unary _ _ "-z" token -> markAsChecked t token
+        TC_Nullary _ _ token -> markAsChecked t token
+
         T_DollarBraced _ _ l -> maybeToList $ do
-            let string = bracedString t
+            let string = concat $ oversimplify l
             let modifier = getBracedModifier string
             guard $ any (`isPrefixOf` modifier) ["=", ":="]
             return (t, t, getBracedReference string, DataString $ SourceFrom [l])
 
-        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&2 modifies foo
+        T_FdRedirect _ ('{':var) op -> -- {foo}>&2 modifies foo
             [(t, t, takeWhile (/= '}') var, DataString SourceInteger) | not $ isClosingFileOp op]
 
-        t@(T_CoProc _ name _) ->
+        T_CoProc _ name _ ->
             [(t, t, fromMaybe "COPROC" name, DataArray SourceInteger)]
 
         --Points to 'for' rather than variable
@@ -522,23 +555,26 @@ getModifiedVariables t =
         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
+  where
+    markAsChecked place token = mapMaybe (f place) $ getWordParts token
+    f place t = case t of
+            T_DollarBraced _ _ l ->
+                let str = getBracedReference $ concat $ oversimplify l in do
+                    guard $ isVariableName str
+                    return (place, t, str, DataString SourceChecked)
+            _ -> Nothing
 
 
 -- 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
+        "declare" -> forDeclare
+        "typeset" -> forDeclare
+
         "export" -> if "f" `elem` flags
             then []
             else concatMap getReference rest
-        "declare" -> if
-                any (`elem` flags) ["x", "p"] &&
-                    (not $ any (`elem` flags) ["f", "F"])
+        "local" -> if "x" `elem` flags
             then concatMap getReference rest
             else []
         "trap" ->
@@ -548,6 +584,13 @@ getReferencedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Litera
         "alias" -> [(base, token, name) | token <- rest, name <- getVariablesFromLiteralToken token]
         _ -> []
   where
+    forDeclare =
+            if
+                any (`elem` flags) ["x", "p"] &&
+                    (not $ any (`elem` flags) ["f", "F"])
+            then concatMap getReference rest
+            else []
+
     getReference t@(T_Assignment _ _ name _ value) = [(t, t, name)]
     getReference t@(T_NormalWord _ [T_Literal _ name]) | not ("-" `isPrefixOf` name) = [(t, t, name)]
     getReference _ = []
@@ -569,10 +612,14 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
         "builtin" ->
             getModifiedVariableCommand $ T_SimpleCommand id cmdPrefix rest
         "read" ->
-            let params = map getLiteral rest
-                readArrayVars = getReadArrayVariables rest
-            in
-                catMaybes . (++ readArrayVars) . takeWhile isJust . reverse $ params
+            let fallback = catMaybes $ takeWhile isJust (reverse $ map getLiteral rest)
+            in fromMaybe fallback $ do
+                parsed <- getGnuOpts flagsForRead rest
+                case lookup "a" parsed of
+                    Just (_, var) -> (:[]) <$> getLiteralArray var
+                    Nothing -> return $ catMaybes $
+                        map (getLiteral . snd . snd) $ filter (null . fst) parsed
+
         "getopts" ->
             case rest of
                 opts:var:_ -> maybeToList $ getLiteral var
@@ -583,8 +630,8 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
         "export" ->
             if "f" `elem` flags then [] else concatMap getModifierParamString rest
 
-        "declare" -> if any (`elem` flags) ["F", "f", "p"] then [] else declaredVars
-        "typeset" -> declaredVars
+        "declare" -> forDeclare
+        "typeset" -> forDeclare
 
         "local" -> concatMap getModifierParamString rest
         "readonly" ->
@@ -596,6 +643,7 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
             return (base, base, "@", DataString $ SourceFrom params)
 
         "printf" -> maybeToList $ getPrintfVariable rest
+        "wait" ->   maybeToList $ getWaitVariable rest
 
         "mapfile" -> maybeToList $ getMapfileArray base rest
         "readarray" -> maybeToList $ getMapfileArray base rest
@@ -615,6 +663,8 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
         T_NormalWord id1 [T_DoubleQuoted id2 [T_Literal id3 (stripEquals s)]]
     stripEqualsFrom t = t
 
+    forDeclare = if any (`elem` flags) ["F", "f", "p"] then [] else declaredVars
+
     declaredVars = concatMap (getModifierParam defaultType) rest
       where
         defaultType = if any (`elem` flags) ["a", "A"] then DataArray else DataString
@@ -653,36 +703,39 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
                 _            -> 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"
+    getPrintfVariable list = getFlagAssignedVariable "v" (SourceFrom list) $ getBsdOpts "v:" list
+    getWaitVariable   list = getFlagAssignedVariable "p" SourceInteger     $ return $ getGenericOpts list
+
+    getFlagAssignedVariable str dataSource maybeFlags = do
+        flags <- maybeFlags
+        (_, (flag, value)) <- find ((== str) . fst) flags
+        variableName <- getLiteralStringExt (const $ return "!") value
+        let (baseName, index) = span (/= '[') variableName
+        return (base, value, baseName, (if null index then DataString else DataArray) dataSource)
 
     -- 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
+    -- where only the first non-option one is used if any.
+    getMapfileArray base rest = parseArgs `mplus` fallback
+      where
+        parseArgs :: Maybe (Token, Token, String, DataType)
+        parseArgs = do
+            args <- getGnuOpts "d:n:O:s:u:C:c:t" rest
+            case [y | ("",(_,y)) <- args] of
+                [] ->
+                    return (base, base, "MAPFILE", DataArray SourceExternal)
+                first:_ -> do
+                    name <- getLiteralString first
+                    guard $ isVariableName name
+                    return (base, first, name, DataArray SourceExternal)
+        -- If arg parsing fails (due to bad or new flags), get the last variable name
+        fallback :: Maybe (Token, Token, String, DataType)
+        fallback = do
+            (name, token) <- listToMaybe . mapMaybe f $ reverse rest
+            return (base, token, name, DataArray SourceExternal)
+        f arg = do
+            name <- getLiteralString arg
+            guard $ isVariableName name
+            return (name, arg)
 
     -- get the FLAGS_ variable created by a shflags DEFINE_ call
     getFlagVariable (n:v:_) = do
@@ -692,28 +745,23 @@ getModifiedVariableCommand base@(T_SimpleCommand id cmdPrefix (T_NormalWord _ (T
 
 getModifiedVariableCommand _ = []
 
-getIndexReferences s = fromMaybe [] $ do
-    match <- matchRegex re s
-    index <- match !!! 0
-    return $ matchAllStrings variableNameRegex index
+-- Given a NormalWord like foo or foo[$bar], get foo.
+-- Primarily used to get references for [[ -v foo[bar] ]]
+getVariableForTestDashV :: Token -> Maybe String
+getVariableForTestDashV t = do
+    str <- takeWhile ('[' /=) <$> getLiteralStringExt toStr t
+    guard $ isVariableName str
+    return str
   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 "^(\\[.+\\])? *:([^-=?+].*)"
+    -- foo[bar] gets parsed with [bar] as a glob, so undo that
+    toStr (T_Glob _ s) = return s
+    -- Turn foo[$x] into foo[\0] so that we can get the constant array name
+    -- in a non-constant expression (while filtering out foo$x[$y])
+    toStr _ = return "\0"
 
 getReferencedVariables parents t =
     case t of
-        T_DollarBraced id _ l -> let str = bracedString t in
+        T_DollarBraced id _ l -> let str = concat $ oversimplify l in
             (t, t, getBracedReference str) :
                 map (\x -> (l, l, x)) (
                     getIndexReferences str
@@ -728,7 +776,7 @@ getReferencedVariables parents t =
         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
+            if isDereferencingBinaryOp op
             then concatMap (getIfReference t) [lhs, rhs]
             else []
 
@@ -738,7 +786,7 @@ getReferencedVariables parents t =
             (t, t, "output")
             ]
 
-        t@(T_FdRedirect _ ('{':var) op) -> -- {foo}>&- references and closes foo
+        T_FdRedirect _ ('{':var) op -> -- {foo}>&- references and closes foo
             [(t, t, takeWhile (/= '}') var) | isClosingFileOp op]
         x -> getReferencedVariableCommand x
   where
@@ -755,19 +803,18 @@ getReferencedVariables parents t =
 
     literalizer t = case t of
         T_Glob _ s -> return s    -- Also when parsed as globs
-        _          -> Nothing
+        _          -> []
 
     getIfReference context token = maybeToList $ do
-            str@(h:_) <- getLiteralStringExt literalizer token
-            when (isDigit h) $ fail "is a number"
+            str <- getVariableForTestDashV token
             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
 
+isDereferencingBinaryOp = (`elem` ["-eq", "-ne", "-lt", "-le", "-gt", "-ge"])
+
 dataTypeFrom defaultType v = (case v of T_Array {} -> DataArray; _ -> defaultType) $ SourceFrom [v]
 
 
@@ -790,16 +837,6 @@ 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 (getLiteralStringDef " " token)
 
@@ -808,77 +845,15 @@ getVariablesFromLiteralToken token =
 prop_getVariablesFromLiteral1 =
     getVariablesFromLiteral "$foo${bar//a/b}$BAZ" == ["foo", "bar", "BAZ"]
 getVariablesFromLiteral string =
-    map (!! 0) $ matchAllSubgroups variableRegex string
+    map head $ 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 = headOrDefault "" $ 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.
-
--- 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
+    params <- ask
+    when (shellType params `elem` l ) c
 
 
 filterByAnnotation asSpec params =
@@ -907,45 +882,15 @@ isCountingReference _ = False
 -- FIXME: doesn't handle ${a:+$var} vs ${a:+"$var"}
 isQuotedAlternativeReference t =
     case t of
-        T_DollarBraced _ _ _ ->
-            getBracedModifier (bracedString t) `matches` re
+        T_DollarBraced _ _ l ->
+            getBracedModifier (concat $ oversimplify l) `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 str t = getOpts str $ getAllFlags t
-getBsdOpts str t = getOpts str $ getLeadingFlags t
-getOpts :: String -> [(Token, String)] -> Maybe [(String, Token)]
-getOpts string flags = process flags
-  where
-    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 $ null flag2
-                more <- process rest
-                return $ (flag1, token2) : more
-            else do
-                more <- process rest2
-                return $ (flag1, token1) : more
-
-supportsArrays shell = shell == Bash || shell == Ksh
+supportsArrays Bash = True
+supportsArrays Ksh = True
+supportsArrays _ = False
 
 -- Returns true if the shell is Bash or Ksh (sorry for the name, Ksh)
 isBashLike :: Parameters -> Bool
@@ -956,5 +901,23 @@ isBashLike params =
         Dash -> False
         Sh -> False
 
+isTrueAssignmentSource c =
+    case c of
+        DataString SourceChecked -> False
+        DataString SourceDeclaration -> False
+        DataArray SourceChecked -> False
+        DataArray SourceDeclaration -> False
+        _ -> True
+
+modifiesVariable params token name =
+    or $ map check flow
+  where
+    flow = getVariableFlow params token
+    check t =
+        case t of
+            Assignment (_, _, n, source) -> isTrueAssignmentSource source && n == name
+            _ -> False
+
+
 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Checker.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2022 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -20,9 +20,10 @@
 {-# LANGUAGE TemplateHaskell #-}
 module ShellCheck.Checker (checkScript, ShellCheck.Checker.runTests) where
 
+import ShellCheck.Analyzer
+import ShellCheck.ASTLib
 import ShellCheck.Interface
 import ShellCheck.Parser
-import ShellCheck.Analyzer
 
 import Data.Either
 import Data.Functor
@@ -85,7 +86,7 @@ checkScript sys spec = do
                     asCheckSourced = csCheckSourced spec,
                     asExecutionMode = Executed,
                     asTokenPositions = tokenPositions,
-                    asOptionalChecks = csOptionalChecks spec
+                    asOptionalChecks = getEnableDirectives root ++ csOptionalChecks spec
                 } where as = newAnalysisSpec root
         let analysisMessages =
                 maybe []
@@ -156,6 +157,11 @@ checkWithIncludesAndSourcePath includes mapper = getErrors
         siFindSource = mapper
     }
 
+checkWithRcIncludesAndSourcePath rc includes mapper = getErrors
+    (mockRcFile rc $ mockedSystemInterface includes) {
+        siFindSource = mapper
+    }
+
 prop_findsParseIssue = check "echo \"$12\"" == [1037]
 
 prop_commentDisablesParseIssue1 =
@@ -229,9 +235,18 @@ prop_cantSourceDynamic =
 prop_cantSourceDynamic2 =
     [1090] == checkWithIncludes [("lib", "")] "source ~/foo"
 
+prop_canStripPrefixAndSource =
+    null $ checkWithIncludes [("./lib", "")] "source \"$MYDIR/lib\""
+
+prop_canStripPrefixAndSource2 =
+    null $ checkWithIncludes [("./utils.sh", "")] "source \"$(dirname \"${BASH_SOURCE[0]}\")/utils.sh\""
+
 prop_canSourceDynamicWhenRedirected =
     null $ checkWithIncludes [("lib", "")] "#shellcheck source=lib\n. \"$1\""
 
+prop_canRedirectWithSpaces =
+    null $ checkWithIncludes [("my file", "")] "#shellcheck source=\"my file\"\n. \"$1\""
+
 prop_recursiveAnalysis =
     [2086] == checkRecursive [("lib", "echo $1")] "source lib"
 
@@ -270,7 +285,7 @@ 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"
+    3046 `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"
 
@@ -295,6 +310,20 @@ prop_canDisableShebangWarning = null $ result
         csScript = "#shellcheck disable=SC2148\nfoo"
     }
 
+prop_canDisableAllWarnings = result == [2086]
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.sh",
+        csScript = "#!/bin/sh\necho $1\n#shellcheck disable=all\necho `echo $1`"
+    }
+
+prop_canDisableParseErrors = null $ result
+  where
+    result = checkWithSpec [] emptyCheckSpec {
+        csFilename = "file.sh",
+        csScript = "#shellcheck disable=SC1073,SC1072,SC2148\n()"
+    }
+
 prop_shExtensionDoesntMatter = result == [2148]
   where
     result = checkWithSpec [] emptyCheckSpec {
@@ -371,7 +400,7 @@ prop_canEnableOptionalsWithRc = result == [2244]
 
 prop_sourcePathRedirectsName = result == [2086]
   where
-    f "dir/myscript" _ "lib" = return "foo/lib"
+    f "dir/myscript" _ _ "lib" = return "foo/lib"
     result = checkWithIncludesAndSourcePath [("foo/lib", "echo $1")] f emptyCheckSpec {
         csScript = "#!/bin/bash\nsource lib",
         csFilename = "dir/myscript",
@@ -380,22 +409,104 @@ prop_sourcePathRedirectsName = result == [2086]
 
 prop_sourcePathAddsAnnotation = result == [2086]
   where
-    f "dir/myscript" ["mypath"] "lib" = return "foo/lib"
+    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_sourcePathWorksWithSpaces = result == [2086]
+  where
+    f "dir/myscript" _ ["my path"] "lib" = return "foo/lib"
+    result = checkWithIncludesAndSourcePath [("foo/lib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\n# shellcheck source-path='my path'\nsource lib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
 prop_sourcePathRedirectsDirective = result == [2086]
   where
-    f "dir/myscript" _ "lib" = return "foo/lib"
-    f _ _ _ = return "/dev/null"
+    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
     }
 
+prop_rcCanAllowExternalSources = result == [2086]
+  where
+    f "dir/myscript" (Just True) _ "mylib" = return "resolved/mylib"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "external-sources=true" [("resolved/mylib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\nsource mylib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_rcCanDenyExternalSources = result == [2086]
+  where
+    f "dir/myscript" (Just False) _ "mylib" = return "resolved/mylib"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "external-sources=false" [("resolved/mylib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\nsource mylib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_rcCanLeaveExternalSourcesUnspecified = result == [2086]
+  where
+    f "dir/myscript" Nothing _ "mylib" = return "resolved/mylib"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "" [("resolved/mylib", "echo $1")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\nsource mylib",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_fileCanDisableExternalSources = result == [2006, 2086]
+  where
+    f "dir/myscript" (Just True) _ "withExternal" = return "withExternal"
+    f "dir/myscript" (Just False) _ "withoutExternal" = return "withoutExternal"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "external-sources=true" [("withExternal", "echo $1"), ("withoutExternal", "_=`foo`")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\ntrue\nsource withExternal\n# shellcheck external-sources=false\nsource withoutExternal",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_fileCannotEnableExternalSources = result == [1144]
+  where
+    f "dir/myscript" Nothing _ "foo" = return "foo"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "" [("foo", "true")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\n# shellcheck external-sources=true\nsource foo",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_fileCannotEnableExternalSources2 = result == [1144]
+  where
+    f "dir/myscript" (Just False) _ "foo" = return "foo"
+    f a b c d = error $ show ("Unexpected", a, b, c, d)
+    result = checkWithRcIncludesAndSourcePath "external-sources=false" [("foo", "true")] f emptyCheckSpec {
+        csScript = "#!/bin/bash\n# shellcheck external-sources=true\nsource foo",
+        csFilename = "dir/myscript",
+        csCheckSourced = True
+    }
+
+prop_rcCanSuppressEarlyProblems1 = null result
+  where
+    result = checkWithRc "disable=1071" emptyCheckSpec {
+        csScript = "#!/bin/zsh\necho $1"
+    }
+
+prop_rcCanSuppressEarlyProblems2 = null result
+  where
+    result = checkWithRc "disable=1104" emptyCheckSpec {
+        csScript = "!/bin/bash\necho 'hello world'"
+    }
+
 return []
 runTests = $quickCheckAll

src/ShellCheck/Checks/Commands.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2019 Vidar Holen
+    Copyright 2012-2022 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -19,6 +19,7 @@
 -}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE MultiWayIf #-}
 
 -- This module contains checks that examine specific commands by name.
 module ShellCheck.Checks.Commands (checker, optionalChecks, ShellCheck.Checks.Commands.runTests) where
@@ -26,21 +27,28 @@ module ShellCheck.Checks.Commands (checker, optionalChecks, ShellCheck.Checks.Co
 import ShellCheck.AST
 import ShellCheck.ASTLib
 import ShellCheck.AnalyzerLib
+import ShellCheck.CFG
+import qualified ShellCheck.CFGAnalysis as CF
 import ShellCheck.Data
 import ShellCheck.Interface
 import ShellCheck.Parser
+import ShellCheck.Prelude
 import ShellCheck.Regex
 
 import Control.Monad
 import Control.Monad.RWS
 import Data.Char
 import Data.Functor.Identity
+import qualified Data.Graph.Inductive.Graph as G
 import Data.List
 import Data.Maybe
-import qualified Data.Map.Strict as Map
+import qualified Data.Map.Strict as M
+import qualified Data.Set as S
 import Test.QuickCheck.All (forAllProperties)
 import Test.QuickCheck.Test (quickCheckWithResult, stdArgs, maxSuccess)
 
+import Debug.Trace -- STRIP
+
 data CommandName = Exactly String | Basename String
     deriving (Eq, Ord)
 
@@ -52,13 +60,11 @@ verify :: CommandCheck -> String -> Bool
 verify f s = producesComments (getChecker [f]) s == Just True
 verifyNot f s = producesComments (getChecker [f]) s == Just False
 
-arguments (T_SimpleCommand _ _ (cmd:args)) = args
-
 commandChecks :: [CommandCheck]
 commandChecks = [
     checkTr
     ,checkFindNameGlob
-    ,checkNeedlessExpr
+    ,checkExpr
     ,checkGrepRe
     ,checkTrapQuotes
     ,checkReturn
@@ -95,7 +101,15 @@ commandChecks = [
     ,checkSudoArgs
     ,checkSourceArgs
     ,checkChmodDashr
+    ,checkXargsDashi
+    ,checkUnquotedEchoSpaces
+    ,checkEvalArray
     ]
+    ++ map checkArgComparison ("alias" : declaringCommands)
+    ++ map checkMaskedReturns declaringCommands
+    ++ map checkMultipleDeclaring declaringCommands
+    ++ map checkBackreferencingDeclaration declaringCommands
+
 
 optionalChecks = map fst optionalCommandChecks
 optionalCommandChecks :: [(CheckDescription, CommandCheck)]
@@ -107,7 +121,7 @@ optionalCommandChecks = [
         cdNegative = "command -v javac"
     }, checkWhich)
     ]
-optionalCheckMap = Map.fromList $ map (\(desc, check) -> (cdName desc, check)) optionalCommandChecks
+optionalCheckMap = M.fromList $ map (\(desc, check) -> (cdName desc, check)) optionalCommandChecks
 
 prop_verifyOptionalExamples = all check optionalCommandChecks
   where
@@ -115,27 +129,68 @@ prop_verifyOptionalExamples = all check optionalCommandChecks
       verify check (cdPositive desc)
       && verifyNot check (cdNegative desc)
 
-buildCommandMap :: [CommandCheck] -> Map.Map CommandName (Token -> Analysis)
-buildCommandMap = foldl' addCheck Map.empty
+-- Run a check against the getopt parser. If it fails, the lists are empty.
+checkGetOpts str flags args f =
+    flags == actualFlags && args == actualArgs
+  where
+    toTokens = map (T_Literal (Id 0)) . words
+    opts = fromMaybe [] $ f (toTokens str)
+    actualFlags = filter (not . null) $ map fst opts
+    actualArgs = [onlyLiteralString x | ("", (_, x)) <- opts]
+
+-- Short options
+prop_checkGetOptsS1 = checkGetOpts "-f x" ["f"] [] $ getOpts (True, True) "f:" []
+prop_checkGetOptsS2 = checkGetOpts "-fx" ["f"] [] $ getOpts (True, True) "f:" []
+prop_checkGetOptsS3 = checkGetOpts "-f -x" ["f", "x"] [] $ getOpts (True, True) "fx" []
+prop_checkGetOptsS4 = checkGetOpts "-f -x" ["f"] [] $ getOpts (True, True) "f:" []
+prop_checkGetOptsS5 = checkGetOpts "-fx" [] [] $ getOpts (True, True) "fx:" []
+
+prop_checkGenericOptsS1 = checkGetOpts "-f x" ["f"] [] $ return . getGenericOpts
+prop_checkGenericOptsS2 = checkGetOpts "-abc x" ["a", "b", "c"] [] $ return . getGenericOpts
+prop_checkGenericOptsS3 = checkGetOpts "-abc -x" ["a", "b", "c", "x"] [] $ return . getGenericOpts
+prop_checkGenericOptsS4 = checkGetOpts "-x" ["x"] [] $ return . getGenericOpts
+
+-- Long options
+prop_checkGetOptsL1 = checkGetOpts "--foo=bar baz" ["foo"] ["baz"] $ getOpts (True, False) "" [("foo", True)]
+prop_checkGetOptsL2 = checkGetOpts "--foo bar baz" ["foo"] ["baz"] $ getOpts (True, False) "" [("foo", True)]
+prop_checkGetOptsL3 = checkGetOpts "--foo baz" ["foo"] ["baz"] $ getOpts (True, True) "" []
+prop_checkGetOptsL4 = checkGetOpts "--foo baz" [] [] $ getOpts (True, False) "" []
+
+prop_checkGenericOptsL1 = checkGetOpts "--foo=bar" ["foo"] [] $ return . getGenericOpts
+prop_checkGenericOptsL2 = checkGetOpts "--foo bar" ["foo"] ["bar"] $ return . getGenericOpts
+prop_checkGenericOptsL3 = checkGetOpts "-x --foo" ["x", "foo"] [] $ return . getGenericOpts
+
+-- Know when to terminate
+prop_checkGetOptsT1 = checkGetOpts "-a x -b" ["a", "b"] ["x"] $ getOpts (True, True) "ab" []
+prop_checkGetOptsT2 = checkGetOpts "-a x -b" ["a"] ["x","-b"] $ getOpts (False, True) "ab" []
+prop_checkGetOptsT3 = checkGetOpts "-a -- -b" ["a"] ["-b"] $ getOpts (True, True) "ab" []
+prop_checkGetOptsT4 = checkGetOpts "-a -- -b" ["a", "b"] [] $ getOpts (True, True) "a:b" []
+
+prop_checkGenericOptsT1 = checkGetOpts "-x -- -y" ["x"] ["-y"] $ return . getGenericOpts
+prop_checkGenericOptsT2 = checkGetOpts "-xy --" ["x", "y"] [] $ return . getGenericOpts
+
+
+buildCommandMap :: [CommandCheck] -> M.Map CommandName (Token -> Analysis)
+buildCommandMap = foldl' addCheck M.empty
   where
     addCheck map (CommandCheck name function) =
-        Map.insertWith composeAnalyzers name function map
+        M.insertWith composeAnalyzers name function map
 
 
-checkCommand :: Map.Map CommandName (Token -> Analysis) -> Token -> Analysis
+checkCommand :: M.Map CommandName (Token -> Analysis) -> Token -> Analysis
 checkCommand map t@(T_SimpleCommand id cmdPrefix (cmd:rest)) = sequence_ $ do
     name <- getLiteralString cmd
     return $
         if '/' `elem` name
         then
-            Map.findWithDefault nullCheck (Basename $ basename name) map t
+            M.findWithDefault nullCheck (Basename $ basename name) map t
         else if name == "builtin" && not (null rest) then
             let t' = T_SimpleCommand id cmdPrefix rest
                 selectedBuiltin = fromMaybe "" $ getLiteralString . head $ rest
-            in Map.findWithDefault nullCheck (Exactly selectedBuiltin) map t'
+            in M.findWithDefault nullCheck (Exactly selectedBuiltin) map t'
         else do
-            Map.findWithDefault nullCheck (Exactly name) map t
-            Map.findWithDefault nullCheck (Basename name) map t
+            M.findWithDefault nullCheck (Exactly name) map t
+            M.findWithDefault nullCheck (Basename name) map t
 
   where
     basename = reverse . takeWhile (/= '/') . reverse
@@ -157,22 +212,22 @@ checker spec params = getChecker $ commandChecks ++ optionals
     optionals =
         if "all" `elem` keys
         then map snd optionalCommandChecks
-        else mapMaybe (\x -> Map.lookup x optionalCheckMap) keys
+        else mapMaybe (\x -> M.lookup x optionalCheckMap) keys
 
 prop_checkTr1 = verify checkTr "tr [a-f] [A-F]"
 prop_checkTr2 = verify checkTr "tr 'a-z' 'A-Z'"
-prop_checkTr2a= verify checkTr "tr '[a-z]' '[A-Z]'"
+prop_checkTr2a = verify checkTr "tr '[a-z]' '[A-Z]'"
 prop_checkTr3 = verifyNot checkTr "tr -d '[:lower:]'"
-prop_checkTr3a= verifyNot checkTr "tr -d '[:upper:]'"
-prop_checkTr3b= verifyNot checkTr "tr -d '|/_[:upper:]'"
+prop_checkTr3a = verifyNot checkTr "tr -d '[:upper:]'"
+prop_checkTr3b = verifyNot checkTr "tr -d '|/_[:upper:]'"
 prop_checkTr4 = verifyNot checkTr "ls [a-z]"
 prop_checkTr5 = verify checkTr "tr foo bar"
 prop_checkTr6 = verify checkTr "tr 'hello' 'world'"
 prop_checkTr8 = verifyNot checkTr "tr aeiou _____"
 prop_checkTr9 = verifyNot checkTr "a-z n-za-m"
-prop_checkTr10= verifyNot checkTr "tr --squeeze-repeats rl lr"
-prop_checkTr11= verifyNot checkTr "tr abc '[d*]'"
-prop_checkTr12= verifyNot checkTr "tr '[=e=]' 'e'"
+prop_checkTr10 = verifyNot checkTr "tr --squeeze-repeats rl lr"
+prop_checkTr11 = verifyNot checkTr "tr abc '[d*]'"
+prop_checkTr12 = verifyNot checkTr "tr '[=e=]' 'e'"
 checkTr = CommandCheck (Basename "tr") (mapM_ f . arguments)
   where
     f w | isGlob w = -- The user will go [ab] -> '[ab]' -> 'ab'. Fixme?
@@ -199,27 +254,81 @@ prop_checkFindNameGlob3 = verifyNot checkFindNameGlob "find * -name '*.php'"
 checkFindNameGlob = CommandCheck (Basename "find") (f . arguments)  where
     acceptsGlob s = s `elem` [ "-ilname", "-iname", "-ipath", "-iregex", "-iwholename", "-lname", "-name", "-path", "-regex", "-wholename" ]
     f [] = return ()
-    f (x:xs) = g x xs
-    g _ [] = return ()
-    g a (b:r) = do
+    f (x:xs) = foldr g (const $ return ()) xs x
+    g b acc a = do
         forM_ (getLiteralString a) $ \s -> when (acceptsGlob s && isGlob b) $
             warn (getId b) 2061 $ "Quote the parameter to " ++ s ++ " so the shell won't interpret it."
-        g b r
+        acc b
 
 
-prop_checkNeedlessExpr = verify checkNeedlessExpr "foo=$(expr 3 + 2)"
-prop_checkNeedlessExpr2 = verify checkNeedlessExpr "foo=`echo \\`expr 3 + 2\\``"
-prop_checkNeedlessExpr3 = verifyNot checkNeedlessExpr "foo=$(expr foo : regex)"
-prop_checkNeedlessExpr4 = verifyNot checkNeedlessExpr "foo=$(expr foo \\< regex)"
-checkNeedlessExpr = CommandCheck (Basename "expr") f where
-    f t =
+prop_checkExpr = verify checkExpr "foo=$(expr 3 + 2)"
+prop_checkExpr2 = verify checkExpr "foo=`echo \\`expr 3 + 2\\``"
+prop_checkExpr3 = verifyNot checkExpr "foo=$(expr foo : regex)"
+prop_checkExpr4 = verifyNot checkExpr "foo=$(expr foo \\< regex)"
+prop_checkExpr5 = verify checkExpr "# shellcheck disable=SC2003\nexpr match foo bar"
+prop_checkExpr6 = verify checkExpr "# shellcheck disable=SC2003\nexpr foo : fo*"
+prop_checkExpr7 = verify checkExpr "# shellcheck disable=SC2003\nexpr 5 -3"
+prop_checkExpr8 = verifyNot checkExpr "# shellcheck disable=SC2003\nexpr \"$@\""
+prop_checkExpr9 = verifyNot checkExpr "# shellcheck disable=SC2003\nexpr 5 $rest"
+prop_checkExpr10 = verify checkExpr "# shellcheck disable=SC2003\nexpr length \"$var\""
+prop_checkExpr11 = verify checkExpr "# shellcheck disable=SC2003\nexpr foo > bar"
+prop_checkExpr12 = verify checkExpr "# shellcheck disable=SC2003\nexpr 1 | 2"
+prop_checkExpr13 = verify checkExpr "# shellcheck disable=SC2003\nexpr 1 * 2"
+prop_checkExpr14 = verify checkExpr "# shellcheck disable=SC2003\nexpr \"$x\" >=  \"$y\""
+
+checkExpr = CommandCheck (Basename "expr") f where
+    f t = do
         when (all (`notElem` exceptions) (words $ arguments t)) $
             style (getId $ getCommandTokenOrThis t) 2003
                 "expr is antiquated. Consider rewriting this using $((..)), ${} or [[ ]]."
+
+        case arguments t of
+            [lhs, op, rhs] -> do
+                checkOp lhs
+                case getWordParts op of
+                    [T_Glob _ "*"] ->
+                        err (getId op) 2304
+                            "* must be escaped to multiply: \\*. Modern $((x * y)) avoids this issue."
+                    [T_Literal _ ":"] | isGlob rhs ->
+                        warn (getId rhs) 2305
+                            "Quote regex argument to expr to avoid it expanding as a glob."
+                    _ -> return ()
+
+            [single] | not (willSplit single) ->
+                warn (getId single) 2307
+                    "'expr' expects 3+ arguments but sees 1. Make sure each operator/operand is a separate argument, and escape <>&|."
+
+            [first, second] |
+                (fromMaybe "" $ getLiteralString first) /= "length"
+                  && not (willSplit first || willSplit second) -> do
+                    checkOp first
+                    warn (getId t) 2307
+                        "'expr' expects 3+ arguments, but sees 2. Make sure each operator/operand is a separate argument, and escape <>&|."
+
+            (first:rest) -> do
+                checkOp first
+                forM_ rest $ \t ->
+                    -- We already find 95%+ of multiplication and regex earlier, so don't bother classifying this further.
+                    when (isGlob t) $ warn (getId t) 2306 "Escape glob characters in arguments to expr to avoid pathname expansion."
+
+            _ -> return ()
+
     -- These operators are hard to replicate in POSIX
-    exceptions = [ ":", "<", ">", "<=", ">=" ]
+    exceptions = [ ":", "<", ">", "<=", ">=",
+        -- We can offer better suggestions for these
+        "match", "length", "substr", "index"]
     words = mapMaybe getLiteralString
 
+    checkOp side =
+        case getLiteralString side of
+            Just "match" -> msg "'expr match' has unspecified results. Prefer 'expr str : regex'."
+            Just "length" -> msg "'expr length' has unspecified results. Prefer ${#var}."
+            Just "substr" -> msg "'expr substr' has unspecified results. Prefer 'cut' or ${var#???}."
+            Just "index" -> msg "'expr index' has unspecified results. Prefer x=${var%%[chars]*}; $((${#x}+1))."
+            _ -> return ()
+      where
+        msg = info (getId side) 2308
+
 
 prop_checkGrepRe1 = verify checkGrepRe "cat foo | grep *.mp3"
 prop_checkGrepRe2 = verify checkGrepRe "grep -Ev cow*test *.mp3"
@@ -230,20 +339,20 @@ prop_checkGrepRe6 = verifyNot checkGrepRe "grep foo \\*.mp3"
 prop_checkGrepRe7 = verify checkGrepRe "grep *foo* file"
 prop_checkGrepRe8 = verify checkGrepRe "ls | grep foo*.jpg"
 prop_checkGrepRe9 = verifyNot checkGrepRe "grep '[0-9]*' file"
-prop_checkGrepRe10= verifyNot checkGrepRe "grep '^aa*' file"
-prop_checkGrepRe11= verifyNot checkGrepRe "grep --include=*.png foo"
-prop_checkGrepRe12= verifyNot checkGrepRe "grep -F 'Foo*' file"
-prop_checkGrepRe13= verifyNot checkGrepRe "grep -- -foo bar*"
-prop_checkGrepRe14= verifyNot checkGrepRe "grep -e -foo bar*"
-prop_checkGrepRe15= verifyNot checkGrepRe "grep --regex -foo bar*"
-prop_checkGrepRe16= verifyNot checkGrepRe "grep --include 'Foo*' file"
-prop_checkGrepRe17= verifyNot checkGrepRe "grep --exclude 'Foo*' file"
-prop_checkGrepRe18= verifyNot checkGrepRe "grep --exclude-dir 'Foo*' file"
-prop_checkGrepRe19= verify checkGrepRe "grep -- 'Foo*' file"
-prop_checkGrepRe20= verifyNot checkGrepRe "grep --fixed-strings 'Foo*' file"
-prop_checkGrepRe21= verifyNot checkGrepRe "grep -o 'x*' file"
-prop_checkGrepRe22= verifyNot checkGrepRe "grep --only-matching 'x*' file"
-prop_checkGrepRe23= verifyNot checkGrepRe "grep '.*' file"
+prop_checkGrepRe10 = verifyNot checkGrepRe "grep '^aa*' file"
+prop_checkGrepRe11 = verifyNot checkGrepRe "grep --include=*.png foo"
+prop_checkGrepRe12 = verifyNot checkGrepRe "grep -F 'Foo*' file"
+prop_checkGrepRe13 = verifyNot checkGrepRe "grep -- -foo bar*"
+prop_checkGrepRe14 = verifyNot checkGrepRe "grep -e -foo bar*"
+prop_checkGrepRe15 = verifyNot checkGrepRe "grep --regex -foo bar*"
+prop_checkGrepRe16 = verifyNot checkGrepRe "grep --include 'Foo*' file"
+prop_checkGrepRe17 = verifyNot checkGrepRe "grep --exclude 'Foo*' file"
+prop_checkGrepRe18 = verifyNot checkGrepRe "grep --exclude-dir 'Foo*' file"
+prop_checkGrepRe19 = verify checkGrepRe "grep -- 'Foo*' file"
+prop_checkGrepRe20 = verifyNot checkGrepRe "grep --fixed-strings 'Foo*' file"
+prop_checkGrepRe21 = verifyNot checkGrepRe "grep -o 'x*' file"
+prop_checkGrepRe22 = verifyNot checkGrepRe "grep --only-matching 'x*' file"
+prop_checkGrepRe23 = verifyNot checkGrepRe "grep '.*' file"
 
 checkGrepRe = CommandCheck (Basename "grep") check where
     check cmd = f cmd (arguments cmd)
@@ -283,21 +392,15 @@ checkGrepRe = CommandCheck (Basename "grep") check where
         candidates =
             sampleWords ++ map (\(x:r) -> toUpper x : r) sampleWords
 
-    getSuspiciousRegexWildcard str =
-        if not $ str `matches` contra
-        then do
-            match <- matchRegex suspicious str
-            str <- match !!! 0
-            str !!! 0
-        else
-            fail "looks good"
-      where
-        suspicious = mkRegex "([A-Za-z1-9])\\*"
-        contra = mkRegex "[^a-zA-Z1-9]\\*|[][^$+\\\\]"
+    getSuspiciousRegexWildcard str = case matchRegex suspicious str of
+        Just [[c]] | not (str `matches` contra) -> Just c
+        _ -> fail "looks good"
+    suspicious = mkRegex "([A-Za-z1-9])\\*"
+    contra = mkRegex "[^a-zA-Z1-9]\\*|[][^$+\\\\]"
 
 
 prop_checkTrapQuotes1 = verify checkTrapQuotes "trap \"echo $num\" INT"
-prop_checkTrapQuotes1a= verify checkTrapQuotes "trap \"echo `ls`\" INT"
+prop_checkTrapQuotes1a = verify checkTrapQuotes "trap \"echo `ls`\" INT"
 prop_checkTrapQuotes2 = verifyNot checkTrapQuotes "trap 'echo $num' INT"
 prop_checkTrapQuotes3 = verify checkTrapQuotes "trap \"echo $((1+num))\" EXIT DEBUG"
 checkTrapQuotes = CommandCheck (Exactly "trap") (f . arguments) where
@@ -378,9 +481,16 @@ prop_checkUnusedEchoEscapes2 = verifyNot checkUnusedEchoEscapes "echo -e 'foi\\n
 prop_checkUnusedEchoEscapes3 = verify checkUnusedEchoEscapes "echo \"n:\\t42\""
 prop_checkUnusedEchoEscapes4 = verifyNot checkUnusedEchoEscapes "echo lol"
 prop_checkUnusedEchoEscapes5 = verifyNot checkUnusedEchoEscapes "echo -n -e '\n'"
+prop_checkUnusedEchoEscapes6 = verify checkUnusedEchoEscapes "echo '\\506'"
+prop_checkUnusedEchoEscapes7 = verify checkUnusedEchoEscapes "echo '\\5a'"
+prop_checkUnusedEchoEscapes8 = verifyNot checkUnusedEchoEscapes "echo '\\8a'"
+prop_checkUnusedEchoEscapes9 = verifyNot checkUnusedEchoEscapes "echo '\\d5a'"
+prop_checkUnusedEchoEscapes10 = verify checkUnusedEchoEscapes "echo '\\x4a'"
+prop_checkUnusedEchoEscapes11 = verify checkUnusedEchoEscapes "echo '\\xat'"
+prop_checkUnusedEchoEscapes12 = verifyNot checkUnusedEchoEscapes "echo '\\xth'"
 checkUnusedEchoEscapes = CommandCheck (Basename "echo") f
   where
-    hasEscapes = mkRegex "\\\\[rnt]"
+    hasEscapes = mkRegex "\\\\([rntabefv\\']|[0-7]{1,3}|x([0-9]|[A-F]|[a-f]){1,2})"
     f cmd =
         whenShell [Sh, Bash, Ksh] $
             unless (cmd `hasFlag` "e") $
@@ -462,8 +572,8 @@ checkMkdirDashPM = CommandCheck (Basename "mkdir") check
   where
     check t = sequence_ $ do
         let flags = getAllFlags t
-        dashP <- find ((\f -> f == "p" || f == "parents") . snd) flags
-        dashM <- find ((\f -> f == "m" || f == "mode") . snd) flags
+        dashP <- find (\(_,f) -> f == "p" || f == "parents") flags
+        dashM <- find (\(_,f) -> f == "m" || f == "mode") flags
         -- mkdir -pm 0700 dir  is fine, so is ../dir, but dir/subdir is not.
         guard $ any couldHaveSubdirs (drop 1 $ arguments t)
         return $ warn (getId $ fst dashM) 2174 "When used with -p, -m only applies to the deepest directory."
@@ -483,7 +593,7 @@ prop_checkNonportableSignals7 = verifyNot checkNonportableSignals "trap 'stop' i
 checkNonportableSignals = CommandCheck (Exactly "trap") (f . arguments)
   where
     f args = case args of
-        first:rest -> unless (isFlag first) $ mapM_ check rest
+        first:rest | not $ isFlag first -> mapM_ check rest
         _ -> return ()
 
     check param = sequence_ $ do
@@ -520,9 +630,9 @@ checkInteractiveSu = CommandCheck (Basename "su") f
             info (getId cmd) 2117
                 "To run commands as another user, use su -c or sudo."
 
-    undirected (T_Pipeline _ _ l) = length l <= 1
+    undirected (T_Pipeline _ _ (_:_:_)) = False
     -- This should really just be modifications to stdin, but meh
-    undirected (T_Redirecting _ list _) = null list
+    undirected (T_Redirecting _ (_:_) _) = False
     undirected _ = True
 
 
@@ -539,9 +649,8 @@ checkSshCommandString = CommandCheck (Basename "ssh") (f . arguments)
             ([], hostport:r@(_:_)) -> checkArg $ last r
             _ -> return ()
     checkArg (T_NormalWord _ [T_DoubleQuoted id parts]) =
-        case filter (not . isConstant) parts of
-            [] -> return ()
-            (x:_) -> info (getId x) 2029
+        forM_ (find (not . isConstant) parts) $
+            \x -> info (getId x) 2029
                 "Note that, unescaped, this expands on the client side."
     checkArg _ = return ()
 
@@ -555,18 +664,20 @@ prop_checkPrintfVar6 = verify checkPrintfVar "printf foo bar baz"
 prop_checkPrintfVar7 = verify checkPrintfVar "printf -- foo bar baz"
 prop_checkPrintfVar8 = verifyNot checkPrintfVar "printf '%s %s %s' \"${var[@]}\""
 prop_checkPrintfVar9 = verifyNot checkPrintfVar "printf '%s %s %s\\n' *.png"
-prop_checkPrintfVar10= verifyNot checkPrintfVar "printf '%s %s %s' foo bar baz"
-prop_checkPrintfVar11= verifyNot checkPrintfVar "printf '%(%s%s)T' -1"
-prop_checkPrintfVar12= verify checkPrintfVar "printf '%s %s\\n' 1 2 3"
-prop_checkPrintfVar13= verifyNot checkPrintfVar "printf '%s %s\\n' 1 2 3 4"
-prop_checkPrintfVar14= verify checkPrintfVar "printf '%*s\\n' 1"
-prop_checkPrintfVar15= verifyNot checkPrintfVar "printf '%*s\\n' 1 2"
-prop_checkPrintfVar16= verifyNot checkPrintfVar "printf $'string'"
-prop_checkPrintfVar17= verify checkPrintfVar "printf '%-*s\\n' 1"
-prop_checkPrintfVar18= verifyNot checkPrintfVar "printf '%-*s\\n' 1 2"
-prop_checkPrintfVar19= verifyNot checkPrintfVar "printf '%(%s)T'"
-prop_checkPrintfVar20= verifyNot checkPrintfVar "printf '%d %(%s)T' 42"
-prop_checkPrintfVar21= verify checkPrintfVar "printf '%d %(%s)T'"
+prop_checkPrintfVar10 = verifyNot checkPrintfVar "printf '%s %s %s' foo bar baz"
+prop_checkPrintfVar11 = verifyNot checkPrintfVar "printf '%(%s%s)T' -1"
+prop_checkPrintfVar12 = verify checkPrintfVar "printf '%s %s\\n' 1 2 3"
+prop_checkPrintfVar13 = verifyNot checkPrintfVar "printf '%s %s\\n' 1 2 3 4"
+prop_checkPrintfVar14 = verify checkPrintfVar "printf '%*s\\n' 1"
+prop_checkPrintfVar15 = verifyNot checkPrintfVar "printf '%*s\\n' 1 2"
+prop_checkPrintfVar16 = verifyNot checkPrintfVar "printf $'string'"
+prop_checkPrintfVar17 = verify checkPrintfVar "printf '%-*s\\n' 1"
+prop_checkPrintfVar18 = verifyNot checkPrintfVar "printf '%-*s\\n' 1 2"
+prop_checkPrintfVar19 = verifyNot checkPrintfVar "printf '%(%s)T'"
+prop_checkPrintfVar20 = verifyNot checkPrintfVar "printf '%d %(%s)T' 42"
+prop_checkPrintfVar21 = verify checkPrintfVar "printf '%d %(%s)T'"
+prop_checkPrintfVar22 = verify checkPrintfVar "printf '%s\n%s' foo"
+
 checkPrintfVar = CommandCheck (Exactly "printf") (f . arguments) where
     f (doubledash:rest) | getLiteralString doubledash == Just "--" = f rest
     f (dashv:var:rest) | getLiteralString dashv == Just "-v" = f rest
@@ -579,23 +690,24 @@ checkPrintfVar = CommandCheck (Exactly "printf") (f . arguments) where
             let formats = getPrintfFormats string
             let formatCount = length formats
             let argCount = length more
+            let pluraliseIfMany word n = if n > 1 then word ++ "s" else word
 
-            return $
-                case () of
-                    () | argCount == 0 && formatCount == 0 ->
-                        return () -- This is fine
-                    () | formatCount == 0 && argCount > 0 ->
-                        err (getId format) 2182
-                            "This printf format string has no variables. Other arguments are ignored."
-                    () | any mayBecomeMultipleArgs more ->
-                        return () -- We don't know so trust the user
-                    () | argCount < formatCount && onlyTrailingTs formats argCount ->
-                        return () -- Allow trailing %()Ts since they use the current time
-                    () | argCount > 0 && argCount `mod` formatCount == 0 ->
-                        return () -- Great: a suitable number of arguments
-                    () ->
-                        warn (getId format) 2183 $
-                            "This format string has " ++ show formatCount ++ " variables, but is passed " ++ show argCount ++ " arguments."
+            return $ if
+                | argCount == 0 && formatCount == 0 ->
+                    return () -- This is fine
+                | formatCount == 0 && argCount > 0 ->
+                    err (getId format) 2182
+                        "This printf format string has no variables. Other arguments are ignored."
+                | any mayBecomeMultipleArgs more ->
+                    return () -- We don't know so trust the user
+                | argCount < formatCount && onlyTrailingTs formats argCount ->
+                    return () -- Allow trailing %()Ts since they use the current time
+                | argCount > 0 && argCount `mod` formatCount == 0 ->
+                    return () -- Great: a suitable number of arguments
+                | otherwise ->
+                    warn (getId format) 2183 $
+                        "This format string has " ++ show formatCount ++ " " ++ pluraliseIfMany "variable" formatCount ++
+                        ", but is passed " ++ show argCount ++ pluraliseIfMany " argument" argCount ++ "."
 
         unless ('%' `elem` concat (oversimplify format) || isLiteral format) $
           info (getId format) 2059
@@ -610,6 +722,8 @@ prop_checkGetPrintfFormats2 = getPrintfFormats "%0*s" == "*s"
 prop_checkGetPrintfFormats3 = getPrintfFormats "%(%s)T" == "T"
 prop_checkGetPrintfFormats4 = getPrintfFormats "%d%%%(%s)T" == "dT"
 prop_checkGetPrintfFormats5 = getPrintfFormats "%bPassed: %d, %bFailed: %d%b, Skipped: %d, %bErrored: %d%b\\n" == "bdbdbdbdb"
+prop_checkGetPrintfFormats6 = getPrintfFormats "%s%s" == "ss"
+prop_checkGetPrintfFormats7 = getPrintfFormats "%s\n%s" == "ss"
 getPrintfFormats = getFormats
   where
     -- Get the arguments in the string as a string of type characters,
@@ -628,18 +742,18 @@ getPrintfFormats = getFormats
 
     regexBasedGetFormats rest =
         case matchRegex re rest of
-            Just [width, precision, typ, rest] ->
+            Just [width, precision, typ, rest, _] ->
                 (if width == "*" then "*" else "") ++
                 (if precision == "*" then "*" else "") ++
                 typ ++ getFormats rest
             Nothing -> take 1 rest ++ getFormats rest
       where
         -- constructed based on specifications in "man printf"
-        re = mkRegex "#?-?\\+? ?0?(\\*|\\d*)\\.?(\\d*|\\*)([diouxXfFeEgGaAcsbq])(.*)"
-        --            \____ _____/\___ ____/   \____ ____/\_________ _________/ \ /
-        --                 V          V             V               V            V
-        --               flags    field width  precision   format character     rest
-        -- field width and precision can be specified with a '*' instead of a digit,
+        re = mkRegex "#?-?\\+? ?0?(\\*|\\d*)\\.?(\\d*|\\*)([diouxXfFeEgGaAcsbq])((\n|.)*)"
+        --            \____ _____/\___ ____/   \____ ____/\_________ _________/ \______ /
+        --                 V          V             V               V               V
+        --               flags    field width  precision   format character        rest
+        -- field width and precision can be specified with an '*' instead of a digit,
         -- in which case printf will accept one more argument for each '*' used
 
 
@@ -663,17 +777,12 @@ prop_checkSetAssignment5 = verifyNot checkSetAssignment "set 'a=5'"
 prop_checkSetAssignment6 = verifyNot checkSetAssignment "set"
 checkSetAssignment = CommandCheck (Exactly "set") (f . arguments)
   where
-    f (var:value:rest) =
-        let str = literal var in
-            when (isVariableName str || isAssignment str) $
-                msg (getId var)
-    f (var:_) =
-        when (isAssignment $ literal var) $
-            msg (getId var)
+    f (var:rest)
+        | (not (null rest) && isVariableName str) || isAssignment str =
+            warn (getId var) 2121 "To assign a variable, use just 'var=value', no 'set ..'."
+      where str = literal var
     f _ = return ()
 
-    msg id = warn id 2121 "To assign a variable, use just 'var=value', no 'set ..'."
-
     isAssignment str = '=' `elem` str
     literal (T_NormalWord _ l) = concatMap literal l
     literal (T_Literal _ str) = str
@@ -687,8 +796,7 @@ prop_checkExportedExpansions4 = verifyNot checkExportedExpansions "export ${foo?
 checkExportedExpansions = CommandCheck (Exactly "export") (mapM_ check . arguments)
   where
     check t = sequence_ $ do
-        var <- getSingleUnmodifiedVariable t
-        let name = bracedString var
+        name <- getSingleUnmodifiedBracedString t
         return . warn (getId t) 2163 $
             "This does not export '" ++ name ++ "'. Remove $/${} for that, or use ${var?} to quiet."
 
@@ -700,30 +808,43 @@ prop_checkReadExpansions5 = verify checkReadExpansions "read \"$var\""
 prop_checkReadExpansions6 = verify checkReadExpansions "read -a $var"
 prop_checkReadExpansions7 = verifyNot checkReadExpansions "read $1"
 prop_checkReadExpansions8 = verifyNot checkReadExpansions "read ${var?}"
+prop_checkReadExpansions9 = verify checkReadExpansions "read arr[val]"
 checkReadExpansions = CommandCheck (Exactly "read") check
   where
     options = getGnuOpts flagsForRead
     getVars cmd = fromMaybe [] $ do
-        opts <- options cmd
-        return [y | (x,y) <- opts, null x || x == "a"]
+        opts <- options $ arguments cmd
+        return [y | (x,(_, y)) <- opts, null x || x == "a"]
 
-    check cmd = mapM_ warning $ getVars cmd
-    warning t = sequence_ $ do
-        var <- getSingleUnmodifiedVariable t
-        let name = bracedString var
+    check cmd = do
+        mapM_ dollarWarning $ getVars cmd
+        mapM_ arrayWarning $ arguments cmd
+
+    dollarWarning t = sequence_ $ do
+        name <- getSingleUnmodifiedBracedString t
         guard $ isVariableName name   -- e.g. not $1
         return . warn (getId t) 2229 $
             "This does not read '" ++ name ++ "'. Remove $/${} for that, or use ${var?} to quiet."
 
+    arrayWarning word =
+        when (any isUnquotedBracket $ getWordParts word) $
+            warn (getId word) 2313 $
+                "Quote array indices to avoid them expanding as globs."
+
+    isUnquotedBracket t =
+        case t of
+            T_Glob _ ('[':_) -> True
+            _ -> False
+
 -- Return the single variable expansion that makes up this word, if any.
 -- e.g. $foo -> $foo, "$foo"'' -> $foo , "hello $name" -> Nothing
-getSingleUnmodifiedVariable :: Token -> Maybe Token
-getSingleUnmodifiedVariable word =
+getSingleUnmodifiedBracedString :: Token -> Maybe String
+getSingleUnmodifiedBracedString word =
     case getWordParts word of
-        [t@(T_DollarBraced {})] ->
-            let contents = bracedString t
+        [T_DollarBraced _ _ l] ->
+            let contents = concat $ oversimplify l
                 name = getBracedReference contents
-            in guard (contents == name) >> return t
+            in guard (contents == name) >> return contents
         _ -> Nothing
 
 prop_checkAliasesUsesArgs1 = verify checkAliasesUsesArgs "alias a='cp $1 /a'"
@@ -754,6 +875,9 @@ checkAliasesExpandEarly = CommandCheck (Exactly "alias") (f . arguments)
 
 prop_checkUnsetGlobs1 = verify checkUnsetGlobs "unset foo[1]"
 prop_checkUnsetGlobs2 = verifyNot checkUnsetGlobs "unset foo"
+prop_checkUnsetGlobs3 = verify checkUnsetGlobs "unset foo[$i]"
+prop_checkUnsetGlobs4 = verify checkUnsetGlobs "unset foo[x${i}y]"
+prop_checkUnsetGlobs5 = verifyNot checkUnsetGlobs "unset foo]["
 checkUnsetGlobs = CommandCheck (Exactly "unset") (mapM_ check . arguments)
   where
     check arg =
@@ -835,6 +959,22 @@ checkLocalScope = CommandCheck (Exactly "local") $ \t ->
         unless (any isFunctionLike path) $
             err (getId $ getCommandTokenOrThis t) 2168 "'local' is only valid in functions."
 
+prop_checkMultipleDeclaring1 = verify (checkMultipleDeclaring "local") "q() { local readonly var=1; }"
+prop_checkMultipleDeclaring2 = verifyNot (checkMultipleDeclaring "local") "q() { local var=1; }"
+prop_checkMultipleDeclaring3 = verify (checkMultipleDeclaring "readonly") "readonly local foo=5"
+prop_checkMultipleDeclaring4 = verify (checkMultipleDeclaring "export") "export readonly foo=5"
+prop_checkMultipleDeclaring5 = verifyNot (checkMultipleDeclaring "local") "f() { local -r foo=5; }"
+prop_checkMultipleDeclaring6 = verifyNot (checkMultipleDeclaring "declare") "declare -rx foo=5"
+prop_checkMultipleDeclaring7 = verifyNot (checkMultipleDeclaring "readonly") "readonly 'local' foo=5"
+checkMultipleDeclaring cmd = CommandCheck (Exactly cmd) (mapM_ check . arguments)
+  where
+    check t = sequence_ $ do
+        lit <- getUnquotedLiteral t
+        guard $ lit `elem` declaringCommands
+        return $ err (getId $ getCommandTokenOrThis t) 2316 $
+                 "This applies " ++ cmd ++ " to the variable named " ++ lit ++
+                 ", which is probably not what you want. Use a separate command or the appropriate `declare` options instead."
+
 prop_checkDeprecatedTempfile1 = verify checkDeprecatedTempfile "var=$(tempfile)"
 prop_checkDeprecatedTempfile2 = verifyNot checkDeprecatedTempfile "tempfile=$(mktemp)"
 checkDeprecatedTempfile = CommandCheck (Basename "tempfile") $
@@ -853,42 +993,56 @@ prop_checkWhileGetoptsCase2 = verify checkWhileGetoptsCase "while getopts 'a:' x
 prop_checkWhileGetoptsCase3 = verifyNot checkWhileGetoptsCase "while getopts 'a:b' x; do case $x in a) foo;; b) bar;; *) :;esac; done"
 prop_checkWhileGetoptsCase4 = verifyNot checkWhileGetoptsCase "while getopts 'a:123' x; do case $x in a) foo;; [0-9]) bar;; esac; done"
 prop_checkWhileGetoptsCase5 = verifyNot checkWhileGetoptsCase "while getopts 'a:' x; do case $x in a) foo;; \\?) bar;; *) baz;; esac; done"
+prop_checkWhileGetoptsCase6 = verifyNot checkWhileGetoptsCase "while getopts 'a:b' x; do case $y in a) foo;; esac; done"
+prop_checkWhileGetoptsCase7 = verifyNot checkWhileGetoptsCase "while getopts 'a:b' x; do case x$x in xa) foo;; xb) foo;; esac; done"
+prop_checkWhileGetoptsCase8 = verifyNot checkWhileGetoptsCase "while getopts 'a:b' x; do x=a; case $x in a) foo;; esac; done"
 checkWhileGetoptsCase = CommandCheck (Exactly "getopts") f
   where
     f :: Token -> Analysis
-    f t@(T_SimpleCommand _ _ (cmd:arg1:_))  = do
+    f t@(T_SimpleCommand _ _ (cmd:arg1:name:_))  = do
         path <- getPathM t
+        params <- ask
         sequence_ $ do
             options <- getLiteralString arg1
+            getoptsVar <- getLiteralString name
             (T_WhileExpression _ _ body) <- findFirst whileLoop path
-            caseCmd <- mapMaybe findCase body !!! 0
+            caseCmd@(T_CaseExpression _ var _) <- mapMaybe findCase body !!! 0
+
+            -- Make sure getopts name and case variable matches
+            [T_DollarBraced _ _ bracedWord] <- return $ getWordParts var
+            [T_Literal _ caseVar] <- return $ getWordParts bracedWord
+            guard $ caseVar == getoptsVar
+
+            -- Make sure the variable isn't modified
+            guard . not $ modifiesVariable params (T_BraceGroup (Id 0) body) getoptsVar
+
             return $ check (getId arg1) (map (:[]) $ filter (/= ':') options) caseCmd
     f _ = return ()
 
     check :: Id -> [String] -> Token -> Analysis
     check optId opts (T_CaseExpression id _ list) = do
-            unless (Nothing `Map.member` handledMap) $ do
-                mapM_ (warnUnhandled optId id) $ catMaybes $ Map.keys notHandled
+            unless (Nothing `M.member` handledMap) $ do
+                mapM_ (warnUnhandled optId id) $ catMaybes $ M.keys notHandled
 
-                unless (any (`Map.member` handledMap) [Just "*",Just "?"]) $
+                unless (any (`M.member` handledMap) [Just "*",Just "?"]) $
                     warn id 2220 "Invalid flags are not handled. Add a *) case."
 
-            mapM_ warnRedundant $ Map.toList notRequested
+            mapM_ warnRedundant $ M.toList notRequested
 
         where
-            handledMap = Map.fromList (concatMap getHandledStrings list)
-            requestedMap = Map.fromList $ map (\x -> (Just x, ())) opts
+            handledMap = M.fromList (concatMap getHandledStrings list)
+            requestedMap = M.fromList $ map (\x -> (Just x, ())) opts
 
-            notHandled = Map.difference requestedMap handledMap
-            notRequested = Map.difference handledMap requestedMap
+            notHandled = M.difference requestedMap handledMap
+            notRequested = M.difference handledMap requestedMap
 
     warnUnhandled optId caseId str =
-        warn caseId 2213 $ "getopts specified -" ++ str ++ ", but it's not handled by this 'case'."
+        warn caseId 2213 $ "getopts specified -" ++ (e4m str) ++ ", but it's not handled by this 'case'."
 
-    warnRedundant (key, expr) = sequence_ $ do
-        str <- key
-        guard $ str `notElem` ["*", ":", "?"]
-        return $ warn (getId expr) 2214 "This case is not specified by getopts."
+    warnRedundant (Just str, expr)
+        | str `notElem` ["*", ":", "?"] =
+            warn (getId expr) 2214 "This case is not specified by getopts."
+    warnRedundant _ = return ()
 
     getHandledStrings (_, globs, _) =
         map (\x -> (literal x, x)) globs
@@ -899,7 +1053,7 @@ checkWhileGetoptsCase = CommandCheck (Exactly "getopts") f
 
     fromGlob t =
         case t of
-            T_Glob _ ('[':c:']':[]) -> return [c]
+            T_Glob _ ['[', c, ']'] -> return [c]
             T_Glob _ "*" -> return "*"
             T_Glob _ "?" -> return "?"
             _ -> Nothing
@@ -924,17 +1078,17 @@ prop_checkCatastrophicRm4 = verify checkCatastrophicRm "rm -fr /home/$(whoami)/*
 prop_checkCatastrophicRm5 = verifyNot checkCatastrophicRm "rm -r /home/${USER:-thing}/*"
 prop_checkCatastrophicRm6 = verify checkCatastrophicRm "rm --recursive /etc/*$config*"
 prop_checkCatastrophicRm8 = verify checkCatastrophicRm "rm -rf /home"
-prop_checkCatastrophicRm10= verifyNot checkCatastrophicRm "rm -r \"${DIR}\"/{.gitignore,.gitattributes,ci}"
-prop_checkCatastrophicRm11= verify checkCatastrophicRm "rm -r /{bin,sbin}/$exec"
-prop_checkCatastrophicRm12= verify checkCatastrophicRm "rm -r /{{usr,},{bin,sbin}}/$exec"
-prop_checkCatastrophicRm13= verifyNot checkCatastrophicRm "rm -r /{{a,b},{c,d}}/$exec"
+prop_checkCatastrophicRm10 = verifyNot checkCatastrophicRm "rm -r \"${DIR}\"/{.gitignore,.gitattributes,ci}"
+prop_checkCatastrophicRm11 = verify checkCatastrophicRm "rm -r /{bin,sbin}/$exec"
+prop_checkCatastrophicRm12 = verify checkCatastrophicRm "rm -r /{{usr,},{bin,sbin}}/$exec"
+prop_checkCatastrophicRm13 = verifyNot checkCatastrophicRm "rm -r /{{a,b},{c,d}}/$exec"
 prop_checkCatastrophicRmA = verify checkCatastrophicRm "rm -rf /usr /lib/nvidia-current/xorg/xorg"
 prop_checkCatastrophicRmB = verify checkCatastrophicRm "rm -rf \"$STEAMROOT/\"*"
 checkCatastrophicRm = CommandCheck (Basename "rm") $ \t ->
     when (isRecursive t) $
         mapM_ (mapM_ checkWord . braceExpand) $ arguments t
   where
-    isRecursive = any (`elem` ["r", "R", "recursive"]) . map snd . getAllFlags
+    isRecursive = any ((`elem` ["r", "R", "recursive"]) . snd) . getAllFlags
 
     checkWord token =
         case getLiteralString token of
@@ -966,9 +1120,9 @@ checkCatastrophicRm = CommandCheck (Basename "rm") $ \t ->
         f _ = return ""
 
     stripTrailing c = reverse . dropWhile (== c) . reverse
-    skipRepeating c (a:b:rest) | a == b && b == c = skipRepeating c (b:rest)
-    skipRepeating c (a:r) = a:skipRepeating c r
-    skipRepeating _ [] = []
+    skipRepeating c = foldr go []
+      where
+        go a r = a : case r of b:rest | b == c && a == b -> rest; _ -> r
 
     paths = [
         "", "/bin", "/etc", "/home", "/mnt", "/usr", "/usr/share", "/usr/local",
@@ -1039,7 +1193,7 @@ checkFindRedirections = CommandCheck (Basename "find") f
 
 prop_checkWhich = verify checkWhich "which '.+'"
 checkWhich = CommandCheck (Basename "which") $
-    \t -> info (getId $ getCommandTokenOrThis t) 2230 "which is non-standard. Use builtin 'command -v' instead."
+    \t -> info (getId $ getCommandTokenOrThis t) 2230 "'which' is non-standard. Use builtin 'command -v' instead."
 
 prop_checkSudoRedirect1 = verify checkSudoRedirect "sudo echo 3 > /proc/file"
 prop_checkSudoRedirect2 = verify checkSudoRedirect "sudo cmd < input"
@@ -1081,8 +1235,8 @@ prop_checkSudoArgs7 = verifyNot checkSudoArgs "sudo docker export foo"
 checkSudoArgs = CommandCheck (Basename "sudo") f
   where
     f t = sequence_ $ do
-        opts <- parseOpts t
-        let nonFlags = [x | ("",x) <- opts]
+        opts <- parseOpts $ arguments t
+        let nonFlags = [x | ("",(x, _)) <- opts]
         commandArg <- nonFlags !!! 0
         command <- getLiteralString commandArg
         guard $ command `elem` builtins
@@ -1113,5 +1267,205 @@ checkChmodDashr = CommandCheck (Basename "chmod") f
         guard $ flag == "-r"
         return $ warn (getId t) 2253 "Use -R to recurse, or explicitly a-r to remove read permissions."
 
+prop_checkXargsDashi1 = verify checkXargsDashi "xargs -i{} echo {}"
+prop_checkXargsDashi2 = verifyNot checkXargsDashi "xargs -I{} echo {}"
+prop_checkXargsDashi3 = verifyNot checkXargsDashi "xargs sed -i -e foo"
+prop_checkXargsDashi4 = verify checkXargsDashi "xargs -e sed -i foo"
+prop_checkXargsDashi5 = verifyNot checkXargsDashi "xargs -x sed -i foo"
+checkXargsDashi = CommandCheck (Basename "xargs") f
+  where
+    f t = sequence_ $ do
+        opts <- parseOpts $ arguments t
+        (option, value) <- lookup "i" opts
+        return $ info (getId option) 2267 "GNU xargs -i is deprecated in favor of -I{}"
+    parseOpts = getBsdOpts "0oprtxadR:S:J:L:l:n:P:s:e:E:i:I:"
+
+
+prop_checkArgComparison1 = verify (checkArgComparison "declare") "declare a = b"
+prop_checkArgComparison2 = verify (checkArgComparison "declare") "declare a =b"
+prop_checkArgComparison3 = verifyNot (checkArgComparison "declare") "declare a=b"
+prop_checkArgComparison4 = verify (checkArgComparison "export") "export a +=b"
+prop_checkArgComparison7 = verifyNot (checkArgComparison "declare") "declare -a +i foo"
+prop_checkArgComparison8 = verify (checkArgComparison "let") "let x = 0"
+prop_checkArgComparison9 = verify (checkArgComparison "alias") "alias x =0"
+-- This mirrors checkSecondArgIsComparison but for arguments to local/readonly/declare/export
+checkArgComparison cmd = CommandCheck (Exactly cmd) wordsWithEqual
+  where
+    wordsWithEqual t = mapM_ check $ arguments t
+    check arg = do
+      sequence_ $ do
+        str <- getLeadingUnquotedString arg
+        case str of
+            '=':_ ->
+                return $ err (headId arg) 2290 $
+                    "Remove spaces around = to assign."
+            '+':'=':_ ->
+                return $ err (headId arg) 2290 $
+                    "Remove spaces around += to append."
+            _ -> Nothing
+
+       -- 'let' is parsed as a sequence of arithmetic expansions,
+       -- so we want the additional warning for "x="
+      when (cmd == "let") $ sequence_ $ do
+        token <- getTrailingUnquotedLiteral arg
+        str <- getLiteralString token
+        guard $ "=" `isSuffixOf` str
+        return $ err (getId token) 2290 $
+            "Remove spaces around = to assign."
+
+    headId t =
+        case t of
+            T_NormalWord _ (x:_) -> getId x
+            _ -> getId t
+
+
+prop_checkMaskedReturns1 = verify (checkMaskedReturns "local") "f() { local a=$(false); }"
+prop_checkMaskedReturns2 = verify (checkMaskedReturns "declare") "declare a=$(false)"
+prop_checkMaskedReturns3 = verify (checkMaskedReturns "declare") "declare a=\"`false`\""
+prop_checkMaskedReturns4 = verify (checkMaskedReturns "readonly") "readonly a=$(false)"
+prop_checkMaskedReturns5 = verify (checkMaskedReturns "readonly") "readonly a=\"`false`\""
+prop_checkMaskedReturns6 = verifyNot (checkMaskedReturns "declare") "declare a; a=$(false)"
+prop_checkMaskedReturns7 = verifyNot (checkMaskedReturns "local") "f() { local -r a=$(false); }"
+prop_checkMaskedReturns8 = verifyNot (checkMaskedReturns "readonly") "a=$(false); readonly a"
+prop_checkMaskedReturns9 = verify (checkMaskedReturns "typeset") "#!/bin/ksh\n f() { typeset -r x=$(false); }"
+prop_checkMaskedReturns10 = verifyNot (checkMaskedReturns "typeset") "#!/bin/ksh\n function f { typeset -r x=$(false); }"
+prop_checkMaskedReturns11 = verifyNot (checkMaskedReturns "typeset") "#!/bin/bash\n f() { typeset -r x=$(false); }"
+prop_checkMaskedReturns12 = verify (checkMaskedReturns "typeset") "typeset -r x=$(false);"
+prop_checkMaskedReturns13 = verify (checkMaskedReturns "typeset") "f() { typeset -g x=$(false); }"
+prop_checkMaskedReturns14 = verify (checkMaskedReturns "declare") "declare x=${ false; }"
+prop_checkMaskedReturns15 = verify (checkMaskedReturns "declare") "f() { declare x=$(false); }"
+checkMaskedReturns str = CommandCheck (Exactly str) checkCmd
+  where
+    checkCmd t = do
+        path <- getPathM t
+        shell <- asks shellType
+        sequence_ $ do
+            name <- getCommandName t
+
+            let flags = map snd (getAllFlags t)
+            let hasDashR =  "r" `elem` flags
+            let hasDashG =  "g" `elem` flags
+            let isInScopedFunction = any (isScopedFunction shell) path
+
+            let isLocal = not hasDashG && isLocalInFunction name && isInScopedFunction
+            let isReadOnly = name == "readonly" || hasDashR
+
+            -- Don't warn about local variables that are declared readonly,
+            -- because the workaround `local x; x=$(false); local -r x;` is annoying
+            guard . not $ isLocal && isReadOnly
+
+            return $ mapM_ checkArgs $ arguments t
+
+    checkArgs (T_Assignment id _ _ _ word) | any hasReturn $ getWordParts word =
+        warn id 2155 "Declare and assign separately to avoid masking return values."
+    checkArgs _ = return ()
+
+    isLocalInFunction = (`elem` ["local", "declare", "typeset"])
+    isScopedFunction shell t =
+        case t of
+            T_BatsTest {} -> True
+            -- In ksh, only functions declared with 'function' have their own scope
+            T_Function _ (FunctionKeyword hasFunction) _ _ _ -> shell /= Ksh || hasFunction
+            _ -> False
+
+    hasReturn t = case t of
+        T_Backticked {} -> True
+        T_DollarExpansion {} -> True
+        T_DollarBraceCommandExpansion {} -> True
+        _ -> False
+
+
+prop_checkUnquotedEchoSpaces1 = verify checkUnquotedEchoSpaces "echo foo         bar"
+prop_checkUnquotedEchoSpaces2 = verifyNot checkUnquotedEchoSpaces "echo       foo"
+prop_checkUnquotedEchoSpaces3 = verifyNot checkUnquotedEchoSpaces "echo foo  bar"
+prop_checkUnquotedEchoSpaces4 = verifyNot checkUnquotedEchoSpaces "echo 'foo          bar'"
+prop_checkUnquotedEchoSpaces5 = verifyNot checkUnquotedEchoSpaces "echo a > myfile.txt b"
+prop_checkUnquotedEchoSpaces6 = verifyNot checkUnquotedEchoSpaces "        echo foo\\\n        bar"
+checkUnquotedEchoSpaces = CommandCheck (Basename "echo") check
+  where
+    check t = do
+        let args = arguments t
+        m <- asks tokenPositions
+        redir <- getClosestCommandM t
+        sequence_ $ do
+            let positions = mapMaybe (\c -> M.lookup (getId c) m) args
+            let pairs = zip positions (drop 1 positions)
+            (T_Redirecting _ redirTokens _) <- redir
+            let redirPositions = mapMaybe (\c -> fst <$> M.lookup (getId c) m) redirTokens
+            guard $ any (hasSpacesBetween redirPositions) pairs
+            return $ info (getId t) 2291 "Quote repeated spaces to avoid them collapsing into one."
+
+    hasSpacesBetween redirs ((a,b), (c,d)) =
+        posLine a == posLine d
+        && ((posColumn c) - (posColumn b)) >= 4
+        && not (any (\x -> b < x && x < c) redirs)
+
+
+prop_checkEvalArray1 = verify checkEvalArray  "eval $@"
+prop_checkEvalArray2 = verify checkEvalArray  "eval \"${args[@]}\""
+prop_checkEvalArray3 = verify checkEvalArray  "eval \"${args[@]@Q}\""
+prop_checkEvalArray4 = verifyNot checkEvalArray  "eval \"${args[*]@Q}\""
+prop_checkEvalArray5 = verifyNot checkEvalArray  "eval \"$*\""
+checkEvalArray = CommandCheck (Exactly "eval") (mapM_ check . concatMap getWordParts . arguments)
+  where
+    check t =
+        when (isArrayExpansion t) $
+            if isEscaped t
+            then style (getId t) 2293 "When eval'ing @Q-quoted words, use * rather than @ as the index."
+            else warn (getId t) 2294 "eval negates the benefit of arrays. Drop eval to preserve whitespace/symbols (or eval as string)."
+
+    isEscaped q =
+        case q of
+            -- Match ${arr[@]@Q} and ${@@Q} and such
+            T_DollarBraced _ _ l -> 'Q' `elem` getBracedModifier (concat $ oversimplify l)
+            _ -> False
+
+
+prop_checkBackreferencingDeclaration1 = verify (checkBackreferencingDeclaration "declare") "declare x=1 y=foo$x"
+prop_checkBackreferencingDeclaration2 = verify (checkBackreferencingDeclaration "readonly") "readonly x=1 y=$((1+x))"
+prop_checkBackreferencingDeclaration3 = verify (checkBackreferencingDeclaration "local") "local x=1 y=$(echo $x)"
+prop_checkBackreferencingDeclaration4 = verify (checkBackreferencingDeclaration "local") "local x=1 y[$x]=z"
+prop_checkBackreferencingDeclaration5 = verify (checkBackreferencingDeclaration "declare") "declare x=var $x=1"
+prop_checkBackreferencingDeclaration6 = verify (checkBackreferencingDeclaration "declare") "declare x=var $x=1"
+prop_checkBackreferencingDeclaration7 = verify (checkBackreferencingDeclaration "declare") "declare x=var $k=$x"
+checkBackreferencingDeclaration cmd = CommandCheck (Exactly cmd) check
+  where
+    check t = foldM_ perArg M.empty $ arguments t
+
+    perArg leftArgs t =
+        case t of
+            T_Assignment id _ name idx t -> do
+                warnIfBackreferencing leftArgs $ t:idx
+                return $ M.insert name id leftArgs
+            t -> do
+                warnIfBackreferencing leftArgs [t]
+                return leftArgs
+
+    warnIfBackreferencing backrefs l = do
+        references <- findReferences l
+        let reused = M.intersection backrefs references
+        mapM msg $ M.toList reused
+
+    msg (name, id) = warn id 2318 $ "This assignment is used again in this '" ++ cmd ++ "', but won't have taken effect. Use two '" ++ cmd ++ "'s."
+
+    findReferences list = do
+        cfga <- asks cfgAnalysis
+        let graph = CF.graph cfga
+        let nodesMap = CF.tokenToNodes cfga
+        let nodes = S.unions $ map (\id -> M.findWithDefault S.empty id nodesMap) $ map getId $ list
+        let labels = mapMaybe (G.lab graph) $ S.toList nodes
+        let references = M.fromList $ concatMap refFromLabel labels
+        return references
+
+    refFromLabel lab =
+        case lab of
+            CFApplyEffects effects -> mapMaybe refFromEffect effects
+            _ -> []
+    refFromEffect e =
+        case e of
+            IdTagged id (CFReadVariable name) -> return (name, id)
+            _ -> Nothing
+
+
 return []
 runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Checks/ControlFlow.hs

@@ -0,0 +1,101 @@
+{-
+    Copyright 2022 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 #-}
+
+-- Checks that run on the Control Flow Graph (as opposed to the AST)
+-- This is scaffolding for a work in progress.
+
+module ShellCheck.Checks.ControlFlow (checker, optionalChecks, ShellCheck.Checks.ControlFlow.runTests) where
+
+import ShellCheck.AST
+import ShellCheck.ASTLib
+import ShellCheck.CFG hiding (cfgAnalysis)
+import ShellCheck.CFGAnalysis
+import ShellCheck.AnalyzerLib
+import ShellCheck.Data
+import ShellCheck.Interface
+
+import Control.Monad
+import Control.Monad.Reader
+import Data.Graph.Inductive.Graph
+import qualified Data.Map as M
+import qualified Data.Set as S
+import Data.List
+import Data.Maybe
+
+import Test.QuickCheck.All (forAllProperties)
+import Test.QuickCheck.Test (quickCheckWithResult, stdArgs, maxSuccess)
+
+
+optionalChecks :: [CheckDescription]
+optionalChecks = []
+
+-- A check that runs on the entire graph
+type ControlFlowCheck = Analysis
+-- A check invoked once per node, with its (pre,post) data
+type ControlFlowNodeCheck = LNode CFNode -> (ProgramState, ProgramState) -> Analysis
+-- A check invoked once per effect, with its node's (pre,post) data
+type ControlFlowEffectCheck = IdTagged CFEffect -> Node -> (ProgramState, ProgramState) -> Analysis
+
+
+checker :: AnalysisSpec -> Parameters -> Checker
+checker spec params = Checker {
+    perScript = const $ sequence_ controlFlowChecks,
+    perToken = const $ return ()
+}
+
+controlFlowChecks :: [ControlFlowCheck]
+controlFlowChecks = [
+        runNodeChecks controlFlowNodeChecks
+    ]
+
+controlFlowNodeChecks :: [ControlFlowNodeCheck]
+controlFlowNodeChecks = [
+    runEffectChecks controlFlowEffectChecks
+    ]
+
+controlFlowEffectChecks :: [ControlFlowEffectCheck]
+controlFlowEffectChecks = [
+    ]
+
+runNodeChecks :: [ControlFlowNodeCheck] -> ControlFlowCheck
+runNodeChecks perNode = do
+    cfg <- asks cfgAnalysis
+    runOnAll cfg
+  where
+    getData datas n@(node, label) = do
+        (pre, post) <- M.lookup node datas
+        return (n, (pre, post))
+
+    runOn :: (LNode CFNode, (ProgramState, ProgramState)) -> Analysis
+    runOn (node, prepost) = mapM_ (\c -> c node prepost) perNode
+    runOnAll cfg = mapM_ runOn $ mapMaybe (getData $ nodeToData cfg) $ labNodes (graph cfg)
+
+runEffectChecks :: [ControlFlowEffectCheck] -> ControlFlowNodeCheck
+runEffectChecks list = checkNode
+  where
+    checkNode (node, label) prepost =
+        case label of
+            CFApplyEffects effects -> mapM_ (\effect -> mapM_ (\c -> c effect node prepost) list) effects
+            _ -> return ()
+
+
+return []
+runTests =  $( [| $(forAllProperties) (quickCheckWithResult (stdArgs { maxSuccess = 1 }) ) |])

src/ShellCheck/Checks/ShellSupport.hs

@@ -1,5 +1,5 @@
 {-
-    Copyright 2012-2016 Vidar Holen
+    Copyright 2012-2020 Vidar Holen
 
     This file is part of ShellCheck.
     https://www.shellcheck.net
@@ -25,6 +25,7 @@ import ShellCheck.AST
 import ShellCheck.ASTLib
 import ShellCheck.AnalyzerLib
 import ShellCheck.Interface
+import ShellCheck.Prelude
 import ShellCheck.Regex
 
 import Control.Monad
@@ -91,55 +92,57 @@ 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_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_checkBashisms52b = verifyNot checkBashisms "#!/bin/sh\ncmd >& $var"
+prop_checkBashisms52c = verify checkBashisms "#!/bin/sh\ncmd >& $dir/$var"
+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"
@@ -178,6 +181,9 @@ 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 $_"
+prop_checkBashisms97 = verify checkBashisms "#!/bin/sh\necho ${var,}"
+prop_checkBashisms98 = verify checkBashisms "#!/bin/sh\necho ${var^^}"
+prop_checkBashisms99 = verify checkBashisms "#!/bin/dash\necho [^f]oo"
 checkBashisms = ForShell [Sh, Dash] $ \t -> do
     params <- ask
     kludge params t
@@ -186,102 +192,103 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
   kludge params = bashism
    where
     isDash = shellType params == Dash
-    warnMsg id s =
+    warnMsg id code s =
         if isDash
-        then warn id 2169 $ "In dash, " ++ s ++ " not supported."
-        else warn id 2039 $ "In POSIX sh, " ++ s ++ " undefined."
+        then err  id code $ "In dash, " ++ s ++ " not supported."
+        else warn id code $ "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 $((..)) is"
-    bashism (T_SelectIn id _ _ _) = warnMsg id "select loops are"
-    bashism (T_BraceExpansion id _) = warnMsg id "brace expansion is"
-    bashism (T_Condition id DoubleBracket _) = warnMsg id "[[ ]] is"
-    bashism (T_HereString id _) = warnMsg id "here-strings are"
+    bashism (T_ProcSub id _ _) = warnMsg id 3001 "process substitution is"
+    bashism (T_Extglob id _ _) = warnMsg id 3002 "extglob is"
+    bashism (T_DollarSingleQuoted id _) = warnMsg id 3003 "$'..' is"
+    bashism (T_DollarDoubleQuoted id _) = warnMsg id 3004 "$\"..\" is"
+    bashism (T_ForArithmetic id _ _ _ _) = warnMsg id 3005 "arithmetic for loops are"
+    bashism (T_Arithmetic id _) = warnMsg id 3006 "standalone ((..)) is"
+    bashism (T_DollarBracket id _) = warnMsg id 3007 "$[..] in place of $((..)) is"
+    bashism (T_SelectIn id _ _ _) = warnMsg id 3008 "select loops are"
+    bashism (T_BraceExpansion id _) = warnMsg id 3009 "brace expansion is"
+    bashism (T_Condition id DoubleBracket _) = warnMsg id 3010 "[[ ]] is"
+    bashism (T_HereString id _) = warnMsg id 3011 "here-strings are"
     bashism (TC_Binary id SingleBracket op _ _)
         | op `elem` [ "<", ">", "\\<", "\\>", "<=", ">=", "\\<=", "\\>="] =
-            unless isDash $ warnMsg id $ "lexicographical " ++ op ++ " is"
+            unless isDash $ warnMsg id 3012 $ "lexicographical " ++ op ++ " is"
     bashism (TC_Binary id SingleBracket op _ _)
         | op `elem` [ "-ot", "-nt", "-ef" ] =
-            unless isDash $ warnMsg id $ op ++ " is"
+            unless isDash $ warnMsg id 3013 $ op ++ " is"
     bashism (TC_Binary id SingleBracket "==" _ _) =
-            warnMsg id "== in place of = is"
+            warnMsg id 3014 "== in place of = is"
     bashism (TC_Binary id SingleBracket "=~" _ _) =
-            warnMsg id "=~ regex matching is"
+            warnMsg id 3015 "=~ regex matching is"
     bashism (TC_Unary id SingleBracket "-v" _) =
-            warnMsg id "unary -v (in place of [ -n \"${var+x}\" ]) is"
+            warnMsg id 3016 "unary -v (in place of [ -n \"${var+x}\" ]) is"
     bashism (TC_Unary id _ "-a" _) =
-            warnMsg id "unary -a in place of -e is"
+            warnMsg id 3017 "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"
+            warnMsg id 3018 $ filter (/= '|') op ++ " is"
+    bashism (TA_Binary id "**" _ _) = warnMsg id 3019 "exponentials are"
+    bashism (T_FdRedirect id "&" (T_IoFile _ (T_Greater _) _)) = warnMsg id 3020 "&> is"
+    bashism (T_FdRedirect id "" (T_IoFile _ (T_GREATAND _) file)) =
+        unless (all isDigit $ onlyLiteralString file) $ warnMsg id 3021 ">& filename (as opposed to >& fd) is"
+    bashism (T_FdRedirect id ('{':_) _) = warnMsg id 3022 "named file descriptors are"
     bashism (T_FdRedirect id num _)
-        | all isDigit num && length num > 1 = warnMsg id "FDs outside 0-9 are"
+        | all isDigit num && length num > 1 = warnMsg id 3023 "FDs outside 0-9 are"
     bashism (T_Assignment id Append _ _ _) =
-        warnMsg id "+= is"
+        warnMsg id 3024 "+= is"
     bashism (T_IoFile id _ word) | isNetworked =
-            warnMsg id "/dev/{tcp,udp} is"
+            warnMsg id 3025 "/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"
+            warnMsg id 3026 "^ in place of ! in glob bracket expressions is"
 
     bashism t@(TA_Variable id str _) | isBashVariable str =
-        warnMsg id $ str ++ " is"
+        warnMsg id 3028 $ str ++ " is"
 
     bashism t@(T_DollarBraced id _ token) = do
         mapM_ check expansion
         when (isBashVariable var) $
-                    warnMsg id $ var ++ " is"
+            warnMsg id 3028 $ var ++ " is"
       where
-        str = bracedString t
+        str = concat $ oversimplify token
         var = getBracedReference str
-        check (regex, feature) =
-            when (isJust $ matchRegex regex str) $ warnMsg id feature
+        check (regex, code, feature) =
+            when (isJust $ matchRegex regex str) $ warnMsg id code feature
 
     bashism t@(T_Pipe id "|&") =
-        warnMsg id "|& in place of 2>&1 | is"
+        warnMsg id 3029 "|& in place of 2>&1 | is"
     bashism (T_Array id _) =
-        warnMsg id "arrays are"
+        warnMsg id 3030 "arrays are"
     bashism (T_IoFile id _ t) | isGlob t =
-        warnMsg id "redirecting to/from globs is"
+        warnMsg id 3031 "redirecting to/from globs is"
     bashism (T_CoProc id _ _) =
-        warnMsg id "coproc is"
+        warnMsg id 3032 "coproc is"
 
     bashism (T_Function id _ _ str _) | not (isVariableName str) =
-        warnMsg id "naming functions outside [a-zA-Z_][a-zA-Z0-9_]* is"
+        warnMsg id 3033 "naming functions outside [a-zA-Z_][a-zA-Z0-9_]* is"
 
     bashism (T_DollarExpansion id [x]) | isOnlyRedirection x =
-        warnMsg id "$(<file) to read files is"
+        warnMsg id 3034 "$(<file) to read files is"
     bashism (T_Backticked id [x]) | isOnlyRedirection x =
-        warnMsg id "`<file` to read files is"
+        warnMsg id 3035 "`<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"
+                    warnMsg (getId arg) 3036 "echo flags besides -n"
             else
-                warnMsg (getId arg) "echo flags are"
+                warnMsg (getId arg) 3037 "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"
+        | getLiteralString cmd == Just "exec" && "-" `isPrefixOf` concat (oversimplify arg) =
+            warnMsg (getId arg) 3038 "exec flags are"
     bashism t@(T_SimpleCommand id _ _)
-        | t `isCommand` "let" = warnMsg id "'let' is"
+        | t `isCommand` "let" = warnMsg id 3039 "'let' is"
     bashism t@(T_SimpleCommand _ _ (cmd:args))
         | t `isCommand` "set" = unless isDash $
             checkOptions $ getLiteralArgs args
@@ -289,16 +296,17 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
         -- 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 [] = []
+        getLiteralArgs = foldr go []
+          where
+            go first rest = case getLiteralString first of
+                Just str -> (getId first, str) : rest
+                Nothing -> []
 
         -- 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"
+                  warnMsg oid 3040 $ "set option " <> opt' <> " is"
                 checkFlags (flag:rest)
             | otherwise = checkFlags (flag:opt:rest)
         checkOptions (flag:rest) = checkFlags (flag:rest)
@@ -311,10 +319,10 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                 unless (flag' `matches` validFlagsRegex) $
                   forM_ (tail flag') $ \letter ->
                     when (letter `notElem` optionsSet) $
-                      warnMsg fid $ "set flag " <> ('-':letter:" is")
+                      warnMsg fid 3041 $ "set flag " <> ('-':letter:" is")
                 checkOptions rest
             | beginsWithDoubleDash flag' = do
-                warnMsg fid $ "set flag " <> flag' <> " is"
+                warnMsg fid 3042 $ "set flag " <> flag' <> " is"
                 checkOptions rest
             -- Either a word that doesn't start with a dash, or simply '--',
             -- so stop checking.
@@ -336,16 +344,19 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
         let name = fromMaybe "" $ getCommandName t
             flags = getLeadingFlags t
         in do
+            when (name == "local" && not isDash) $
+                -- This is so commonly accepted that we'll make it a special case
+                warnMsg id 3043 $ "'local' is"
             when (name `elem` unsupportedCommands) $
-                warnMsg id $ "'" ++ name ++ "' is"
+                warnMsg id 3044 $ "'" ++ name ++ "' is"
             sequence_ $ do
                 allowed' <- Map.lookup name allowedFlags
                 allowed <- allowed'
                 (word, flag) <- find
                     (\x -> (not . null . snd $ x) && snd x `notElem` allowed) flags
-                return . warnMsg (getId word) $ name ++ " -" ++ flag ++ " is"
+                return . warnMsg (getId word) 3045 $ name ++ " -" ++ flag ++ " is"
 
-            when (name == "source") $ warnMsg id "'source' in place of '.' is"
+            when (name == "source") $ warnMsg id 3046 "'source' in place of '.' is"
             when (name == "trap") $
                 let
                     check token = sequence_ $ do
@@ -353,12 +364,12 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                         let upper = map toUpper str
                         return $ do
                             when (upper `elem` ["ERR", "DEBUG", "RETURN"]) $
-                                warnMsg (getId token) $ "trapping " ++ str ++ " is"
+                                warnMsg (getId token) 3047 $ "trapping " ++ str ++ " is"
                             when ("SIG" `isPrefixOf` upper) $
-                                warnMsg (getId token)
+                                warnMsg (getId token) 3048
                                     "prefixing signal names with 'SIG' is"
                             when (not isDash && upper /= str) $
-                                warnMsg (getId token)
+                                warnMsg (getId token) 3049
                                     "using lower/mixed case for signal names is"
                 in
                     mapM_ check (drop 1 rest)
@@ -367,13 +378,13 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                 format <- rest !!! 0  -- flags are covered by allowedFlags
                 let literal = onlyLiteralString format
                 guard $ "%q" `isInfixOf` literal
-                return $ warnMsg (getId format) "printf %q is"
+                return $ warnMsg (getId format) 3050 "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 []),
@@ -390,29 +401,35 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
             ("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"
+    bashism t@(T_SourceCommand id src _)
+        | getCommandName src == Just "source" = warnMsg id 3051 "'source' in place of '.' is"
+    bashism (TA_Expansion _ (T_Literal id str : _))
+        | str `matches` radix = warnMsg id 3052 "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")
+        (re $ "^![" ++ varChars ++ "]", 3053, "indirect expansion is"),
+        (re $ "^[" ++ varChars ++ "]+\\[.*\\]$", 3054, "array references are"),
+        (re $ "^![" ++ varChars ++ "]+\\[[*@]]$", 3055, "array key expansion is"),
+        (re $ "^![" ++ varChars ++ "]+[*@]$", 3056, "name matching prefixes are"),
+        (re $ "^[" ++ varChars ++ "*@]+:[^-=?+]", 3057, "string indexing is"),
+        (re $ "^([*@][%#]|#[@*])", 3058, "string operations on $@/$* are"),
+        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?[,^]", 3059, "case modification is"),
+        (re $ "^[" ++ varChars ++ "*@]+(\\[.*\\])?/", 3060, "string replacement is")
         ]
     bashVars = [
+        -- This list deliberately excludes $BASH_VERSION as it's often used
+        -- for shell identification.
         "OSTYPE", "MACHTYPE", "HOSTTYPE", "HOSTNAME",
         "DIRSTACK", "EUID", "UID", "SHLVL", "PIPESTATUS", "SHELLOPTS",
-        "_"
+        "_", "BASHOPTS", "BASHPID", "BASH_ALIASES", "BASH_ARGC",
+        "BASH_ARGV", "BASH_ARGV0", "BASH_CMDS", "BASH_COMMAND",
+        "BASH_EXECUTION_STRING", "BASH_LINENO", "BASH_REMATCH", "BASH_SOURCE",
+        "BASH_SUBSHELL", "BASH_VERSINFO", "EPOCHREALTIME", "EPOCHSECONDS",
+        "FUNCNAME", "GROUPS", "MACHTYPE", "MAPFILE"
         ]
     bashDynamicVars = [ "RANDOM", "SECONDS" ]
     dashVars = [ "_" ]
@@ -427,9 +444,9 @@ checkBashisms = ForShell [Sh, Dash] $ \t -> do
                 _ -> 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_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)"
+prop_checkEchoSed2b = verify checkEchoSed "rm $(sed -e 's,foo,bar,' <<< $cow)"
 checkEchoSed = ForShell [Bash, Ksh] f
   where
     f (T_Redirecting id lefts r) =
@@ -506,20 +523,20 @@ checkMultiDimensionalArrays = ForShell [Bash] f
         case token of
             T_Assignment _ _ name (first:second:_) _ -> about second
             T_IndexedElement _ (first:second:_) _ -> about second
-            T_DollarBraced {} ->
-                when (isMultiDim token) $ about token
+            T_DollarBraced _ _ l ->
+                when (isMultiDim l) $ 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
+    isMultiDim l = getBracedModifier (concat $ oversimplify l) `matches` re
 
 prop_checkPS11 = verify checkPS1Assignments "PS1='\\033[1;35m\\$ '"
-prop_checkPS11a= verify checkPS1Assignments "export 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=$'\\e[3m; '"
+prop_checkPS14a = verify checkPS1Assignments "export PS1=$'\\e[3m; '"
 prop_checkPS15 = verifyNot checkPS1Assignments "PS1='\\[\\033[1;35m\\]\\$ '"
 prop_checkPS16 = verifyNot checkPS1Assignments "PS1='\\[\\e1m\\e[1m\\]\\$ '"
 prop_checkPS17 = verifyNot checkPS1Assignments "PS1='e033x1B'"

src/ShellCheck/Data.hs

@@ -2,9 +2,27 @@ module ShellCheck.Data where
 
 import ShellCheck.Interface
 import Data.Version (showVersion)
-import Paths_ShellCheck (version)
 
-shellcheckVersion = showVersion version
+
+{-
+If you are here because you saw an error about Paths_ShellCheck in this file,
+simply comment out the import below and define the version as a constant string.
+
+Instead of:
+
+    import Paths_ShellCheck (version)
+    shellcheckVersion = showVersion version
+
+Use:
+
+    -- import Paths_ShellCheck (version)
+    shellcheckVersion = "kludge"
+
+-}
+
+import Paths_ShellCheck (version)
+shellcheckVersion = showVersion version  -- VERSIONSTRING
+
 
 internalVariables = [
     -- Generic
@@ -12,23 +30,26 @@ internalVariables = [
 
     -- Bash
     "BASH", "BASHOPTS", "BASHPID", "BASH_ALIASES", "BASH_ARGC",
-    "BASH_ARGV", "BASH_CMDS", "BASH_COMMAND", "BASH_EXECUTION_STRING",
-    "BASH_LINENO", "BASH_REMATCH", "BASH_SOURCE", "BASH_SUBSHELL",
-    "BASH_VERSINFO", "BASH_VERSION", "COMP_CWORD", "COMP_KEY",
-    "COMP_LINE", "COMP_POINT", "COMP_TYPE", "COMP_WORDBREAKS",
-    "COMP_WORDS", "COPROC", "DIRSTACK", "EUID", "FUNCNAME", "GROUPS",
-    "HISTCMD", "HOSTNAME", "HOSTTYPE", "LINENO", "MACHTYPE", "MAPFILE",
-    "OLDPWD", "OPTARG", "OPTIND", "OSTYPE", "PIPESTATUS", "PPID", "PWD",
-    "RANDOM", "READLINE_LINE", "READLINE_POINT", "REPLY", "SECONDS",
-    "SHELLOPTS", "SHLVL", "UID", "BASH_ENV", "BASH_XTRACEFD", "CDPATH",
-    "COLUMNS", "COMPREPLY", "EMACS", "ENV", "FCEDIT", "FIGNORE",
+    "BASH_ARGV", "BASH_ARGV0", "BASH_CMDS", "BASH_COMMAND",
+    "BASH_EXECUTION_STRING", "BASH_LINENO", "BASH_LOADABLES_PATH",
+    "BASH_REMATCH", "BASH_SOURCE", "BASH_SUBSHELL", "BASH_VERSINFO",
+    "BASH_VERSION", "COMP_CWORD", "COMP_KEY", "COMP_LINE", "COMP_POINT",
+    "COMP_TYPE", "COMP_WORDBREAKS", "COMP_WORDS", "COPROC", "DIRSTACK",
+    "EPOCHREALTIME", "EPOCHSECONDS", "EUID", "FUNCNAME", "GROUPS", "HISTCMD",
+    "HOSTNAME", "HOSTTYPE", "LINENO", "MACHTYPE", "MAPFILE", "OLDPWD",
+    "OPTARG", "OPTIND", "OSTYPE", "PIPESTATUS", "PPID", "PWD", "RANDOM",
+    "READLINE_ARGUMENT", "READLINE_LINE", "READLINE_MARK", "READLINE_POINT",
+    "REPLY", "SECONDS", "SHELLOPTS", "SHLVL", "SRANDOM", "UID", "BASH_COMPAT",
+    "BASH_ENV", "BASH_XTRACEFD", "CDPATH", "CHILD_MAX", "COLUMNS",
+    "COMPREPLY", "EMACS", "ENV", "EXECIGNORE", "FCEDIT", "FIGNORE",
     "FUNCNEST", "GLOBIGNORE", "HISTCONTROL", "HISTFILE", "HISTFILESIZE",
     "HISTIGNORE", "HISTSIZE", "HISTTIMEFORMAT", "HOME", "HOSTFILE", "IFS",
-    "IGNOREEOF", "INPUTRC", "LANG", "LC_ALL", "LC_COLLATE", "LC_CTYPE",
-    "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",
+    "IGNOREEOF", "INPUTRC", "INSIDE_EMACS", "LANG", "LC_ALL", "LC_COLLATE",
+    "LC_CTYPE", "LC_MESSAGES", "LC_MONETARY", "LC_NUMERIC", "LC_TIME",
+    "LINES", "MAIL", "MAILCHECK", "MAILPATH", "OPTERR", "PATH",
+    "POSIXLY_CORRECT", "PROMPT_COMMAND", "PROMPT_DIRTRIM", "PS0", "PS1",
+    "PS2", "PS3", "PS4", "SHELL", "TIMEFORMAT", "TMOUT", "TMPDIR",
+    "auto_resume", "histchars",
 
     -- Other
     "USER", "TZ", "TERM", "LOGNAME", "LD_LIBRARY_PATH", "LANGUAGE", "DISPLAY",
@@ -43,13 +64,18 @@ internalVariables = [
     "flags_error", "flags_return"
   ]
 
-specialVariablesWithoutSpaces = [
-    "$", "-", "?", "!", "#"
+specialIntegerVariables = [
+    "$", "?", "!", "#"
   ]
+
+specialVariablesWithoutSpaces = "-" : specialIntegerVariables
+
 variablesWithoutSpaces = specialVariablesWithoutSpaces ++ [
-    "BASHPID", "BASH_ARGC", "BASH_LINENO", "BASH_SUBSHELL", "EUID", "LINENO",
-    "OPTIND", "PPID", "RANDOM", "SECONDS", "SHELLOPTS", "SHLVL", "UID",
-    "COLUMNS", "HISTFILESIZE", "HISTSIZE", "LINES"
+    "BASHPID", "BASH_ARGC", "BASH_LINENO", "BASH_SUBSHELL", "EUID",
+    "EPOCHREALTIME", "EPOCHSECONDS", "LINENO", "OPTIND", "PPID", "RANDOM",
+    "READLINE_ARGUMENT", "READLINE_MARK", "READLINE_POINT", "SECONDS",
+    "SHELLOPTS", "SHLVL", "SRANDOM", "UID", "COLUMNS", "HISTFILESIZE",
+    "HISTSIZE", "LINES"
 
     -- shflags
     , "FLAGS_ERROR", "FLAGS_FALSE", "FLAGS_TRUE"
@@ -95,10 +121,10 @@ commonCommands = [
 
 nonReadingCommands = [
     "alias", "basename", "bg", "cal", "cd", "chgrp", "chmod", "chown",
-    "cp", "du", "echo", "export", "false", "fg", "fuser", "getconf",
+    "cp", "du", "echo", "export", "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"
+    "set", "sleep", "touch", "trap", "ulimit", "unalias", "uname"
     ]
 
 sampleWords = [
@@ -138,3 +164,6 @@ shellForExecutable name =
         _ -> Nothing
 
 flagsForRead = "sreu:n:N:i:p:a:t:"
+flagsForMapfile = "d:n:O:s:u:C:c:t"
+
+declaringCommands = ["local", "declare", "export", "readonly", "typeset", "let"]

src/ShellCheck/Debug.hs

@@ -0,0 +1,313 @@
+{-
+
+This file contains useful functions for debugging and developing ShellCheck.
+
+To invoke them interactively, run:
+
+    cabal repl
+
+At the ghci prompt, enter:
+
+    :load ShellCheck.Debug
+
+You can now invoke the functions. Here are some examples:
+
+    shellcheckString "echo $1"
+    stringToAst "(( x+1 ))"
+    stringToCfg "if foo; then bar; else baz; fi"
+    writeFile "/tmp/test.dot" $ stringToCfgViz "while foo; do bar; done"
+
+The latter file can be rendered to png with GraphViz:
+
+    dot -Tpng /tmp/test.dot > /tmp/test.png
+
+To run all unit tests in a module:
+
+    ShellCheck.Parser.runTests
+    ShellCheck.Analytics.runTests
+
+To run a specific test:
+
+    :load ShellCheck.Analytics
+    prop_checkUuoc3
+
+If you make code changes, reload in seconds at any time with:
+
+    :r
+
+===========================================================================
+
+Crash course in printf debugging in Haskell:
+
+    import Debug.Trace
+
+    greet 0 = return ()
+    -- Print when a function is invoked
+    greet n | trace ("calling greet " ++ show n) False = undefined
+    greet n = do
+        putStrLn "Enter name"
+        name <- getLine
+        -- Print at some point in any monadic function
+        traceM $ "user entered " ++ name
+        putStrLn $ "Hello " ++ name
+        -- Print a value before passing it on
+        greet $ traceShowId (n - 1)
+
+
+===========================================================================
+
+If you want to invoke `ghci` directly, such as on `shellcheck.hs`, to
+debug all of ShellCheck including I/O, you may see an error like this:
+
+    src/ShellCheck/Data.hs:5:1: error:
+        Could not load module ‘Paths_ShellCheck’
+    it is a hidden module in the package ‘ShellCheck-0.8.0’
+
+This can easily be circumvented by running `./setgitversion` or manually
+editing src/ShellCheck/Data.hs to replace the auto-deduced version number
+with a constant string as indicated.
+
+Afterwards, you can run the ShellCheck tool, as if from the shell, with:
+
+    $ ghci shellcheck.hs
+    ghci> runMain ["-x", "file.sh"]
+
+-}
+
+module ShellCheck.Debug () where
+
+import ShellCheck.Analyzer
+import ShellCheck.AST
+import ShellCheck.CFG
+import ShellCheck.Checker
+import ShellCheck.CFGAnalysis as CF
+import ShellCheck.Interface
+import ShellCheck.Parser
+import ShellCheck.Prelude
+
+import Control.Monad
+import Control.Monad.Identity
+import Control.Monad.RWS
+import Control.Monad.Writer
+import Data.Graph.Inductive.Graph as G
+import Data.List
+import Data.Maybe
+import qualified Data.Map as M
+import qualified Data.Set as S
+
+
+-- Run all of ShellCheck (minus output formatters)
+shellcheckString :: String -> CheckResult
+shellcheckString scriptString =
+    runIdentity $ checkScript dummySystemInterface checkSpec
+  where
+    checkSpec :: CheckSpec
+    checkSpec = emptyCheckSpec {
+        csScript = scriptString
+    }
+
+dummySystemInterface :: SystemInterface Identity
+dummySystemInterface = mockedSystemInterface [
+    -- A tiny, fake filesystem for sourced files
+    ("lib/mylib1.sh", "foo=$(cat $1 | wc -l)"),
+    ("lib/mylib2.sh", "bar=42")
+    ]
+
+-- Parameters used when generating Control Flow Graphs
+cfgParams :: CFGParameters
+cfgParams = CFGParameters {
+    cfLastpipe = False,
+    cfPipefail = False
+}
+
+-- An example script to play with
+exampleScript :: String
+exampleScript = unlines [
+    "#!/bin/sh",
+    "count=0",
+    "for file in *",
+    "do",
+    "  (( count++ ))",
+    "done",
+    "echo $count"
+    ]
+
+-- Parse the script string into ShellCheck's ParseResult
+parseScriptString :: String -> ParseResult
+parseScriptString scriptString =
+    runIdentity $ parseScript dummySystemInterface parseSpec
+  where
+    parseSpec :: ParseSpec
+    parseSpec = newParseSpec {
+        psFilename = "myscript",
+        psScript = scriptString
+    }
+
+
+-- Parse the script string into an Abstract Syntax Tree
+stringToAst :: String -> Token
+stringToAst scriptString =
+    case maybeRoot of
+        Just root -> root
+        Nothing -> error $ "Script failed to parse: " ++ show parserWarnings
+  where
+    parseResult :: ParseResult
+    parseResult = parseScriptString scriptString
+
+    maybeRoot :: Maybe Token
+    maybeRoot = prRoot parseResult
+
+    parserWarnings :: [PositionedComment]
+    parserWarnings = prComments parseResult
+
+
+astToCfgResult :: Token -> CFGResult
+astToCfgResult = buildGraph cfgParams
+
+astToDfa :: Token -> CFGAnalysis
+astToDfa = analyzeControlFlow cfgParams
+
+astToCfg :: Token -> CFGraph
+astToCfg = cfGraph . astToCfgResult
+
+stringToCfg :: String -> CFGraph
+stringToCfg = astToCfg . stringToAst
+
+stringToDfa :: String -> CFGAnalysis
+stringToDfa = astToDfa . stringToAst
+
+cfgToGraphViz :: CFGraph -> String
+cfgToGraphViz = cfgToGraphVizWith show
+
+stringToCfgViz :: String -> String
+stringToCfgViz = cfgToGraphViz . stringToCfg
+
+stringToDfaViz :: String -> String
+stringToDfaViz = dfaToGraphViz . stringToDfa
+
+-- Dump a Control Flow Graph as GraphViz with extended information
+stringToDetailedCfgViz :: String -> String
+stringToDetailedCfgViz scriptString = cfgToGraphVizWith nodeLabel graph
+  where
+    ast :: Token
+    ast = stringToAst scriptString
+
+    cfgResult :: CFGResult
+    cfgResult = astToCfgResult ast
+
+    graph :: CFGraph
+    graph = cfGraph cfgResult
+
+    idToToken :: M.Map Id Token
+    idToToken = M.fromList $ execWriter $ doAnalysis (\c -> tell [(getId c, c)]) ast
+
+    idToNode :: M.Map Id (Node, Node)
+    idToNode = cfIdToRange cfgResult
+
+    nodeToStartIds :: M.Map Node (S.Set Id)
+    nodeToStartIds =
+        M.fromListWith S.union $
+            map (\(id, (start, _)) -> (start, S.singleton id)) $
+                M.toList idToNode
+
+    nodeToEndIds :: M.Map Node (S.Set Id)
+    nodeToEndIds =
+        M.fromListWith S.union $
+            map (\(id, (_, end)) -> (end, S.singleton id)) $
+                M.toList idToNode
+
+    formatId :: Id -> String
+    formatId id = fromMaybe ("Unknown " ++ show id) $ do
+        (OuterToken _ token) <- M.lookup id idToToken
+        firstWord <- words (show token) !!! 0
+        -- Strip off "Inner_"
+        (_ : tokenName) <- return $ dropWhile (/= '_') firstWord
+        return $ tokenName ++ " " ++ show id
+
+    formatGroup :: S.Set Id -> String
+    formatGroup set = intercalate ", " $ map formatId $ S.toList set
+
+    nodeLabel (node, label) = unlines [
+        show node ++ ". " ++ show label,
+        "Begin: " ++ formatGroup (M.findWithDefault S.empty node nodeToStartIds),
+        "End: " ++ formatGroup (M.findWithDefault S.empty node nodeToEndIds)
+        ]
+
+
+-- Dump a Control Flow Graph with Data Flow Analysis as GraphViz
+dfaToGraphViz :: CF.CFGAnalysis -> String
+dfaToGraphViz analysis = cfgToGraphVizWith label $ CF.graph analysis
+  where
+    label (node, label) =
+        let
+            desc = show node ++ ". " ++ show label
+        in
+            fromMaybe ("No DFA available\n\n" ++ desc) $ do
+                (pre, post) <- M.lookup node $ CF.nodeToData analysis
+                return $ unlines [
+                    "Precondition: " ++ show pre,
+                    "",
+                    desc,
+                    "",
+                    "Postcondition: " ++ show post
+                    ]
+
+
+-- Dump an Control Flow Graph to GraphViz with a given node formatter
+cfgToGraphVizWith :: (LNode CFNode -> String) -> CFGraph -> String
+cfgToGraphVizWith nodeLabel graph = concat [
+    "digraph {\n",
+    concatMap dumpNode (labNodes graph),
+    concatMap dumpLink (labEdges graph),
+    tagVizEntries graph,
+    "}\n"
+    ]
+  where
+    dumpNode l@(node, label) = show node ++ " [label=" ++ quoteViz (nodeLabel l) ++ "]\n"
+    dumpLink (from, to, typ) = show from ++ " -> " ++ show to ++ " [style=" ++ quoteViz (edgeStyle typ)  ++ "]\n"
+    edgeStyle CFEFlow = "solid"
+    edgeStyle CFEExit = "bold"
+    edgeStyle CFEFalseFlow = "dotted"
+
+quoteViz str = "\"" ++ escapeViz str ++ "\""
+escapeViz [] = []
+escapeViz (c:rest) =
+    case c of
+        '\"' -> '\\' : '\"' : escapeViz rest
+        '\n' -> '\\' : 'l' : escapeViz rest
+        '\\' -> '\\' : '\\' : escapeViz rest
+        _ -> c : escapeViz rest
+
+
+-- Dump an Abstract Syntax Tree (or branch thereof) to GraphViz format
+astToGraphViz :: Token -> String
+astToGraphViz token = concat [
+    "digraph {\n",
+    formatTree token,
+    "}\n"
+    ]
+  where
+    formatTree :: Token -> String
+    formatTree t = snd $ execRWS (doStackAnalysis push pop t) () []
+
+    push :: Token -> RWS () String [Int] ()
+    push (OuterToken (Id n) inner) = do
+        stack <- get
+        put (n : stack)
+        case stack of
+            [] -> return ()
+            (top:_) -> tell $ show top ++ " -> " ++ show n ++ "\n"
+        tell $ show n ++ " [label=" ++ quoteViz (show n ++ ": " ++ take 32 (show inner)) ++ "]\n"
+
+    pop :: Token -> RWS () String [Int] ()
+    pop _ = modify tail
+
+
+-- For each entry point, set the rank so that they'll align in the graph
+tagVizEntries :: CFGraph -> String
+tagVizEntries graph = "{ rank=same " ++ rank ++ " }"
+  where
+    entries = mapMaybe find $ labNodes graph
+    find (node, CFEntryPoint name) = return (node, name)
+    find _ = Nothing
+    rank = unwords $ map (\(c, _) -> show c) entries

src/ShellCheck/Fixer.hs

@@ -22,6 +22,8 @@
 module ShellCheck.Fixer (applyFix, removeTabStops, mapPositions, Ranged(..), runTests) where
 
 import ShellCheck.Interface
+import ShellCheck.Prelude
+import Control.Monad
 import Control.Monad.State
 import Data.Array
 import Data.List
@@ -35,7 +37,7 @@ class Ranged a where
     end     :: a -> Position
     overlap :: a -> a -> Bool
     overlap x y =
-        (yStart >= xStart && yStart < xEnd) || (yStart < xStart && yEnd > xStart)
+        xEnd > yStart && yEnd > xStart
         where
             yStart = start y
             yEnd = end y
@@ -86,6 +88,7 @@ instance Ranged Replacement where
 instance Monoid Fix where
     mempty = newFix
     mappend = (<>)
+    mconcat = foldl mappend mempty -- fold left to right since <> discards right on overlap
 
 instance Semigroup Fix where
     f1 <> f2 =
@@ -228,7 +231,7 @@ applyReplacement2 rep string = do
 
     let (l1, l2) = tmap posLine originalPos in
         when (l1 /= 1 || l2 /= 1) $
-            error "ShellCheck internal error, please report: bad cross-line fix"
+            error $ pleaseReport "bad cross-line fix"
 
     let replacer = repString rep
     let shift = (length replacer) - (oldEnd - oldStart)
@@ -273,10 +276,10 @@ 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
+        case target `compare` pivot of
+            LT -> f sum target left
+            GT -> f (sum+cumulative) target right
+            EQ -> 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
@@ -285,10 +288,10 @@ 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)
+        case key `compare` pivot of
+            LT -> PSBranch pivot (f left) right (sum + value)
+            GT -> PSBranch pivot left (f right) sum
+            EQ -> PSBranch pivot left right (sum + value)
 
 prop_pstreeSumsCorrectly kvs targets =
   let

src/ShellCheck/Formatter/CheckStyle.hs

@@ -48,7 +48,7 @@ outputResults cr sys =
     fileGroups = groupWith sourceFile comments
     outputGroup group = do
         let filename = sourceFile (head group)
-        result <- (siReadFile sys) filename
+        result <- siReadFile sys (Just True) filename
         let contents = either (const "") id result
         outputFile filename contents group
 
@@ -88,7 +88,7 @@ outputError file error = putStrLn $ concat [
 attr s v = concat [ s, "='", escape v, "' " ]
 escape = concatMap escape'
 escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
-isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
+isOk x = any ($ x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
 
 severity "error" = "error"
 severity "warning" = "warning"

src/ShellCheck/Formatter/Diff.hs

@@ -38,9 +38,6 @@ import System.FilePath
 
 import Test.QuickCheck
 
-import Debug.Trace
-ltt x = trace (show x) x
-
 format :: FormatterOptions -> IO Formatter
 format options = do
     foundIssues <- newIORef False
@@ -90,7 +87,7 @@ reportResult foundIssues reportedIssues color result sys = do
     mapM_ output $ M.toList fixmap
   where
     output (name, fix) = do
-        file <- (siReadFile sys) name
+        file <- siReadFile sys (Just True) name
         case file of
             Right contents -> do
                 putStrLn $ formatDoc color $ makeDiff name contents fix
@@ -206,10 +203,9 @@ formatDoc color (DiffDoc name lf regions) =
 buildFixMap :: [Fix] -> M.Map String Fix
 buildFixMap fixes = perFile
   where
-    splitFixes = concatMap splitFixByFile fixes
+    splitFixes = splitFixByFile $ mconcat 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

src/ShellCheck/Formatter/Format.hs

@@ -28,6 +28,7 @@ import Data.Array
 import Data.List
 import System.IO
 import System.Info
+import System.Environment
 
 -- A formatter that carries along an arbitrary piece of data
 data Formatter = Formatter {
@@ -68,12 +69,14 @@ makeNonVirtual comments contents =
 
 
 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
+shouldOutputColor colorOption =
+    case colorOption of
+        ColorAlways -> return True
+        ColorNever -> return False
+        ColorAuto -> do
+            isTerminal <- hIsTerminalDevice stdout
+            term <- lookupEnv "TERM"
+            let windows = "mingw" `isPrefixOf` os
+            let dumbTerm = term `elem` [Just "dumb", Just "", Nothing]
+            let isUsableTty = isTerminal && not windows && not dumbTerm
+            return isUsableTty

src/ShellCheck/Formatter/GCC.hs

@@ -43,7 +43,7 @@ outputAll cr sys = mapM_ f groups
     f :: [PositionedComment] -> IO ()
     f group = do
         let filename = sourceFile (head group)
-        result <- (siReadFile sys) filename
+        result <- siReadFile sys (Just True) filename
         let contents = either (const "") id result
         outputResult filename contents group
 

src/ShellCheck/Formatter/JSON.hs

@@ -23,6 +23,7 @@ module ShellCheck.Formatter.JSON (format) where
 import ShellCheck.Interface
 import ShellCheck.Formatter.Format
 
+import Control.DeepSeq
 import Data.Aeson
 import Data.IORef
 import Data.Monoid
@@ -103,7 +104,7 @@ collectResult ref cr sys = mapM_ f groups
     comments = crComments cr
     groups = groupWith sourceFile comments
     f :: [PositionedComment] -> IO ()
-    f group = modifyIORef ref (\x -> comments ++ x)
+    f group = deepseq comments $ modifyIORef ref (\x -> comments ++ x)
 
 finish ref = do
     list <- readIORef ref

src/ShellCheck/Formatter/JSON1.hs

@@ -23,6 +23,7 @@ module ShellCheck.Formatter.JSON1 (format) where
 import ShellCheck.Interface
 import ShellCheck.Formatter.Format
 
+import Control.DeepSeq
 import Data.Aeson
 import Data.IORef
 import Data.Monoid
@@ -117,10 +118,10 @@ collectResult ref cr sys = mapM_ f groups
     f :: [PositionedComment] -> IO ()
     f group = do
         let filename = sourceFile (head group)
-        result <- siReadFile sys filename
+        result <- siReadFile sys (Just True) filename
         let contents = either (const "") id result
         let comments' = makeNonVirtual comments contents
-        modifyIORef ref (\x -> comments' ++ x)
+        deepseq comments' $ modifyIORef ref (\x -> comments' ++ x)
 
 finish ref = do
     list <- readIORef ref

src/ShellCheck/Formatter/TTY.hs

@@ -23,6 +23,7 @@ import ShellCheck.Fixer
 import ShellCheck.Interface
 import ShellCheck.Formatter.Format
 
+import Control.DeepSeq
 import Control.Monad
 import Data.Array
 import Data.Foldable
@@ -88,7 +89,7 @@ rankError err = (ranking, cSeverity $ pcComment err, cCode $ pcComment err)
 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
+    writeIORef errRef $! force . take max . nubBy equal . sort $ previous ++ current
   where
     fst3 (x,_,_) = x
     equal x y = fst3 x == fst3 y
@@ -121,13 +122,13 @@ outputResult options ref result sys = do
 
 outputForFile color sys comments = do
     let fileName = sourceFile (head comments)
-    result <- (siReadFile sys) fileName
+    result <- siReadFile sys (Just True) 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
+    forM_ groups $ \commentsForLine -> do
         let lineNum = fromIntegral $ lineNo (head commentsForLine)
         let line = if lineNum < 1 || lineNum > lineCount
                         then ""
@@ -136,10 +137,9 @@ outputForFile color sys comments = do
         putStrLn $ color "message" $
            "In " ++ fileName ++" line " ++ show lineNum ++ ":"
         putStrLn (color "source" line)
-        mapM_ (\c -> putStrLn (color (severityText c) $ cuteIndent c)) commentsForLine
+        forM_ commentsForLine $ \c -> putStrLn $ color (severityText c) $ cuteIndent c
         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)
@@ -175,7 +175,7 @@ showFixedString color comments lineNum fileLines =
 cuteIndent :: PositionedComment -> String
 cuteIndent comment =
     replicate (fromIntegral $ colNo comment - 1) ' ' ++
-        makeArrow ++ " " ++ code (codeNo comment) ++ ": " ++ messageText comment
+        makeArrow ++ " " ++ code (codeNo comment) ++ " (" ++ severityText comment ++ "): " ++ messageText comment
   where
     arrow n = '^' : replicate (fromIntegral $ n-2) '-' ++ "^"
     makeArrow =

src/ShellCheck/Interface.hs

@@ -73,15 +73,19 @@ 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:
+    -- | Given:
+    --   What annotations say about including external files (if anything)
+    --   A resolved filename from siFindSource
+    --   Read the file or return an error
+    siReadFile :: Maybe Bool -> String -> m (Either ErrorMessage String),
+    -- | Given:
     --   the current script,
+    --   what annotations say about including external files (if anything)
     --   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
+    siFindSource :: String -> Maybe Bool -> [String] -> String -> m FilePath,
+    -- | Get the configuration file (name, contents) for a filename
     siGetConfig :: String -> m (Maybe (FilePath, String))
 }
 
@@ -313,11 +317,11 @@ mockedSystemInterface files = SystemInterface {
     siGetConfig = const $ return Nothing
 }
   where
-    rf file = return $
+    rf _ file = return $
         case find ((== file) . fst) files of
             Nothing -> Left "File not included in mock."
             Just (_, contents) -> Right contents
-    fs _ _ file = return file
+    fs _ _ _ file = return file
 
 mockRcFile rcfile mock = mock {
     siGetConfig = const . return $ Just (".shellcheckrc", rcfile)

src/ShellCheck/Prelude.hs

@@ -0,0 +1,51 @@
+{-
+    Copyright 2022 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/>.
+-}
+
+-- Generic basic utility functions
+module ShellCheck.Prelude where
+
+import Data.Semigroup
+
+
+-- Get element 0 or a default. Like `head` but safe.
+headOrDefault _ (a:_) = a
+headOrDefault def _   = def
+
+-- Get the last element or a default. Like `last` but safe.
+lastOrDefault def [] = def
+lastOrDefault _ list = last list
+
+--- Get element n of a list, or Nothing. Like `!!` but safe.
+(!!!) list i =
+    case drop i list of
+        []    -> Nothing
+        (r:_) -> Just r
+
+
+-- Like mconcat but for Semigroups
+sconcat1 :: (Semigroup t) => [t] -> t
+sconcat1 [x] = x
+sconcat1 (x:xs) = x <> sconcat1 xs
+
+sconcatOrDefault def [] = def
+sconcatOrDefault _ list = sconcat1 list
+
+-- For more actionable "impossible" errors
+pleaseReport str = "ShellCheck internal error, please report: " ++ str

stack.yaml

@@ -2,7 +2,7 @@
 # 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
+resolver: lts-18.15
 
 # Local packages, usually specified by relative directory name
 packages:

striptests

@@ -29,6 +29,7 @@ detestify() {
       state = 0;
     }
 
+    /STRIP/ { next; }
     /LANGUAGE TemplateHaskell/ { next; }
     /^import.*Test\./ { next; }
 
@@ -75,4 +76,3 @@ find . -name '.git' -prune -o -type f -name '*.hs' -print |
   do
     modify "$file" detestify
   done
-

test/buildtest

@@ -22,13 +22,16 @@ fi
 
 cabal install --dependencies-only --enable-tests "${flags[@]}" ||
   cabal install --dependencies-only "${flags[@]}" ||
-    die "can't install dependencies"
+    cabal install --dependencies-only --max-backjumps -1 "${flags[@]}" ||
+      die "can't install dependencies"
 cabal configure --enable-tests "${flags[@]}" ||
   die "configure failed"
 cabal build ||
   die "build failed"
 cabal test ||
   die "test failed"
+cabal haddock ||
+  die "haddock failed"
 
 sc="$(find . -name shellcheck -type f -perm -111)"
 [ -x "$sc" ] || die "Can't find executable"

test/check_release

@@ -9,7 +9,7 @@ fail() {
 
 if git diff | grep -q ""
 then
-  fail "There are uncommited changes"
+  fail "There are uncommitted changes"
 fi
 
 current=$(git tag --points-at)
@@ -56,19 +56,19 @@ 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 GitHub Build currently passes: https://github.com/koalaman/shellcheck/actions
 $((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 
+$((i++)). Make sure the Hackage package builds.
 
 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++)). Wait for GitHub Actions to build.
 $((j++)). Verify release:
-  a. Check that the new versions are uploaded: https://shellcheck.storage.googleapis.com/index.html
+  a. Check that the new versions are uploaded: https://github.com/koalaman/shellcheck/tags
   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

test/distrotest

@@ -25,6 +25,13 @@ exit 0
 echo "Deleting 'dist' and 'dist-newstyle'..."
 rm -rf dist dist-newstyle
 
+execs=$(find . -name shellcheck)
+
+if [ -n "$execs" ]
+then
+  die "Found unexpected executables. Remove and try again: $execs"
+fi
+
 log=$(mktemp) || die "Can't create temp file"
 date >> "$log" || die "Can't write to log"
 
@@ -63,14 +70,17 @@ debian:testing        apt-get update && apt-get install -y cabal-install
 ubuntu:latest         apt-get update && apt-get install -y cabal-install
 haskell:latest        true
 opensuse/leap:latest  zypper install -y cabal-install ghc
-fedora:latest         dnf install -y cabal-install ghc-template-haskell-devel findutils
-archlinux/base:latest pacman -S -y --noconfirm cabal-install ghc-static base-devel
+fedora:latest         dnf install -y cabal-install ghc-template-haskell-devel findutils libstdc++-static gcc-c++
+archlinux:latest      pacman -S -y --noconfirm cabal-install ghc-static base-devel
 
-# Other versions we want to support
+# Ubuntu LTS
+ubuntu:22.04          apt-get update && apt-get install -y cabal-install
+ubuntu:20.04          apt-get update && apt-get install -y cabal-install
 ubuntu:18.04          apt-get update && apt-get install -y cabal-install
+ubuntu:16.04          apt-get update && apt-get install -y cabal-install
 
-# Misc Haskell including current and latest Stack build
-ubuntu:18.04          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
+# Stack on Ubuntu LTS
+ubuntu:22.04          set -e; apt-get update && apt-get install -y curl && curl -sSL https://get.haskellstack.org/ | sh -s - -f && cd /mnt && exec test/stacktest
 EOF
 
 exit "$final"

test/shellcheck.hs

@@ -4,8 +4,12 @@ import Control.Monad
 import System.Exit
 import qualified ShellCheck.Analytics
 import qualified ShellCheck.AnalyzerLib
+import qualified ShellCheck.ASTLib
+import qualified ShellCheck.CFG
+import qualified ShellCheck.CFGAnalysis
 import qualified ShellCheck.Checker
 import qualified ShellCheck.Checks.Commands
+import qualified ShellCheck.Checks.ControlFlow
 import qualified ShellCheck.Checks.Custom
 import qualified ShellCheck.Checks.ShellSupport
 import qualified ShellCheck.Fixer
@@ -17,8 +21,12 @@ main = do
     results <- sequence [
         ShellCheck.Analytics.runTests
         ,ShellCheck.AnalyzerLib.runTests
+        ,ShellCheck.ASTLib.runTests
+        ,ShellCheck.CFG.runTests
+        ,ShellCheck.CFGAnalysis.runTests
         ,ShellCheck.Checker.runTests
         ,ShellCheck.Checks.Commands.runTests
+        ,ShellCheck.Checks.ControlFlow.runTests
         ,ShellCheck.Checks.Custom.runTests
         ,ShellCheck.Checks.ShellSupport.runTests
         ,ShellCheck.Fixer.runTests

test/stacktest

@@ -3,7 +3,7 @@
 # various resolvers. It's run via distrotest.
 
 resolvers=(
-  nightly-"$(date -d "3 days ago" +"%Y-%m-%d")"
+#  nightly-"$(date -d "3 days ago" +"%Y-%m-%d")"
 )
 
 die() { echo "$*" >&2; exit 1; }
@@ -18,10 +18,11 @@ command -v stack ||
 stack setup        || die "Failed to setup with default resolver"
 stack build --test || die "Failed to build/test with default resolver"
 
+# Nice to haves, but not necessary
 for resolver in "${resolvers[@]}"
 do
-  stack --resolver="$resolver" setup        || die "Failed to setup $resolver"
-  stack --resolver="$resolver" build --test || die "Failed build/test with $resolver!"
+  stack --resolver="$resolver" setup        || die "Failed to setup $resolver. This probably doesn't matter."
+  stack --resolver="$resolver" build --test || die "Failed build/test with $resolver! This probably doesn't matter."
 done
 
 echo "Success"