tests: add shellcheck

.cirrus.yml

@@ -36,3 +36,7 @@ task:
       build_script:
         - nix flake check
         - ./test/nixos-search/ci-test.sh
+
+    - name: shellcheck
+      build_script:
+        - nix shell --inputs-from . nixpkgs#{shellcheck,findutils,gnugrep} -c ./test/shellcheck.sh

test/run-tests.sh

@@ -312,8 +312,14 @@ examples() {
     (cd "$scriptDir/../examples" && nix-shell --run "$script")
 }
 
+shellcheck() {
+    if ! checkFlakeSupport "shellcheck"; then return; fi
+    nix shell --inputs-from "$scriptDir/.." nixpkgs#shellcheck -c "$scriptDir/shellcheck.sh"
+}
+
 all() {
-    buildable
+    buildable "$@"
+    shellcheck
     examples
     flake
     nixosSearch

test/shellcheck.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd "${BASH_SOURCE[0]%/*}/.."
+{
+    # Skip .git dir in all find commands
+    find . -type f ! -path './.git/*' -name '*.sh'
+    # Find files without extensions that have a shell shebang
+    find . -type f ! -path './.git/*' ! -name "*.*" -exec grep -lP '\A^#! */usr/bin/env (?:nix-shell|bash)' {} \;
+} | while IFS= read -r path; do
+    echo "$path"
+    file=${path##*/}
+    dir=${path%/*}
+    # Switch working directory so that shellcheck can access external sources
+    # (via arg `--external-sources`)
+    pushd "$dir" > /dev/null
+    shellcheck --external-sources --shell bash "$file"
+    popd > /dev/null
+done