From 9d64d78c320cfcd89e46d1de53f6c6d8e9487b4f Mon Sep 17 00:00:00 2001
From: Vidar Holen <spam@vidarholen.net>
Date: Sat, 28 Aug 2021 21:19:45 -0700
Subject: [PATCH] Allow running this repo as a pre-commit hook

---
 .dockerignore          |  9 +++------
 .pre-commit-hooks.yaml |  6 ++++++
 Dockerfile             | 18 ++++++++++++++++++
 test/distrotest        | 30 ++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 .pre-commit-hooks.yaml
 create mode 100644 Dockerfile

diff --git a/.dockerignore b/.dockerignore
index 39d8893..49f90c9 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,6 +1,3 @@
-*
-!LICENSE
-!Setup.hs
-!ShellCheck.cabal
-!shellcheck.hs
-!src
+dist
+dist-newstyle
+.git
diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
new file mode 100644
index 0000000..9c5b4bc
--- /dev/null
+++ b/.pre-commit-hooks.yaml
@@ -0,0 +1,6 @@
+- id: shellcheck
+  name: shellcheck
+  description: Static analysis tool for shell scripts
+  types: [shell]
+  language: docker
+  entry: shellcheck
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..0f8e07c
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,18 @@
+# This file builds ShellCheck for pre-commit.
+#
+# It may also be useful for local development, but it is notably NOT
+# used to build the official ShellCheck docker images.
+
+FROM ubuntu:20.04
+RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y cabal-install
+RUN cabal update
+
+# Install dependencies separately for more efficient iteration
+COPY ShellCheck.cabal /build/
+RUN cd /build && cabal install --dependencies-only
+
+# Now build the rest
+COPY . /build/
+RUN cd /build && cabal build shellcheck
+RUN find /build -type f -name shellcheck -perm /111 -exec cp -f {} /bin \;
+ENTRYPOINT ["/bin/shellcheck"]
diff --git a/test/distrotest b/test/distrotest
index 346a706..8aaa84d 100755
--- a/test/distrotest
+++ b/test/distrotest
@@ -1,6 +1,9 @@
 #!/bin/bash
 # This script runs 'buildtest' on each of several distros
 # via Docker.
+
+# shellcheck disable=SC2016
+
 set -o pipefail
 
 exec 3>&1 4>&2
@@ -32,6 +35,33 @@ echo "Logging to $log" >&3
 exec >> "$log" 2>&1
 
 final=0
+
+echo "Trying to build pre-commit docker image"
+if ! docker build --tag precommit .
+then
+  final=1
+  echo "pre-commit image failed to build"
+else
+  if printf '%s\n' '#!/bin/sh' 'echo $1' | docker run -i precommit -
+  then
+    final=1
+    echo "pre-commit image succeeds with incorrect example"
+  fi
+
+  if ! printf '%s\n' '#!/bin/sh' 'echo "$1"' | docker run -i precommit -
+  then
+    final=1
+    echo "pre-commit image fails with correct example"
+  fi
+fi
+
+if [[ $final -ne 0 ]]
+then
+  echo >&3 "pre-commit image failure, see log"
+else
+  echo >&3 "pre-commit image succeeded"
+fi
+
 while read -r distro setup
 do
   [[ "$distro" = "#"* || -z "$distro" ]] && continue