perf(shellcheck): batch pre-commit script checks

.config/flakebox/id

@@ -1 +1 @@
-b3c9ea32bd238c00ccfd8b74c3b0c683441ebb2d67d4c0a47a0065404d27dbf5e33ade808310e029032c69e0d5418ac285a19dee4c331484b51a0924b27fcb50
+d65b7ff6c41916c949fb5e2b5511d6ce5b951e3e878db458c8012df8bc027a93a773b72a53ea93e1533daaf4142447f7f88c8970cc53853baa108eb2dbde40ae

checks/git-hooks.nix

@@ -64,6 +64,10 @@ let
     '';
   };
 
+  shellcheckHooks = mkHookFixture {
+    inherit (flakeboxLib.config.git.pre-commit.hooks) shellcheck;
+  };
+
   stashHooks = mkHookFixture {
     stash-probe = ''
       grep -qx staged tracked.txt
@@ -344,6 +348,50 @@ pkgs.runCommand "git-hooks-tests"
     kill "$background_pid" 2>/dev/null || true
     cd ..
 
+    # ShellCheck is skipped for an empty script set, then receives every tracked
+    # script in one argument-safe invocation. Its failure still fails the hook.
+    mkdir shellcheck-repo
+    cd shellcheck-repo
+    git init -q
+    mkdir fake-shellcheck-bin
+    cat > fake-shellcheck-bin/shellcheck <<'EOF'
+    #!${pkgs.bash}/bin/bash
+    printf 'invocation\n' >> "$FLAKEBOX_SHELLCHECK_LOG"
+    printf '%s\n' "$@" > "$FLAKEBOX_SHELLCHECK_ARGS"
+    exit "''${FLAKEBOX_SHELLCHECK_STATUS:-0}"
+    EOF
+    chmod +x fake-shellcheck-bin/shellcheck
+    export PATH="$PWD/fake-shellcheck-bin:$PATH"
+    export FLAKEBOX_SHELLCHECK_LOG="$PWD/shellcheck.log"
+    export FLAKEBOX_SHELLCHECK_ARGS="$PWD/shellcheck.args"
+
+    printf 'not a script\n' > tracked.txt
+    git add tracked.txt
+    NO_STASH=1 bash ${shellcheckHooks}/misc/git-hooks/pre-commit
+    [ ! -e "$FLAKEBOX_SHELLCHECK_LOG" ]
+
+    printf '#!/bin/sh\n' > 'alpha script.sh'
+    printf '#!/bin/sh\n' > 'literal[glob].sh'
+    # This untracked path makes an unsafe expansion of literal[glob].sh match.
+    printf '#!/bin/sh\n' > literalg.sh
+    git --literal-pathspecs add 'alpha script.sh' 'literal[glob].sh'
+    NO_STASH=1 bash ${shellcheckHooks}/misc/git-hooks/pre-commit
+    [ "$(grep -c '^invocation$' "$FLAKEBOX_SHELLCHECK_LOG")" -eq 1 ]
+    printf '%s\n' \
+      '--severity=warning' \
+      'alpha script.sh' \
+      'literal[glob].sh' > expected-shellcheck.args
+    cmp expected-shellcheck.args "$FLAKEBOX_SHELLCHECK_ARGS"
+
+    set +e
+    FLAKEBOX_SHELLCHECK_STATUS=23 NO_STASH=1 \
+      bash ${shellcheckHooks}/misc/git-hooks/pre-commit
+    shellcheck_failure_status=$?
+    set -e
+    [ "$shellcheck_failure_status" -ne 0 ]
+    [ "$(grep -c '^invocation$' "$FLAKEBOX_SHELLCHECK_LOG")" -eq 2 ]
+    cd ..
+
     # Private patch restoration exposes indexed content to checks and restores
     # tracked worktree changes afterwards without touching the user stash.
     mkdir stash-repo

lib/modules/shellcheck.nix

@@ -21,9 +21,16 @@
   config = lib.mkIf config.shellcheck.enable {
     git.pre-commit.hooks = {
       shellcheck = ''
-        for path in $(echo "$FLAKEBOX_GIT_LS_TEXT" | grep -E '.*\.sh$'); do
-          shellcheck --severity=warning "$path"
-        done
+        shellcheck_paths=()
+        while IFS= read -r path; do
+          if [[ "$path" == *.sh ]]; then
+            shellcheck_paths+=("$path")
+          fi
+        done <<< "$FLAKEBOX_GIT_LS_TEXT"
+
+        if [[ "''${#shellcheck_paths[@]}" -ne 0 ]]; then
+          shellcheck --severity=warning "''${shellcheck_paths[@]}"
+        fi
       '';
     };
 

misc/git-hooks/pre-commit

@@ -107,9 +107,16 @@ export -f check_semgrep
 function check_shellcheck() {
     set -euo pipefail
 
-    for path in $(echo "$FLAKEBOX_GIT_LS_TEXT" | grep -E '.*\.sh$'); do
-      shellcheck --severity=warning "$path"
-    done
+    shellcheck_paths=()
+    while IFS= read -r path; do
+      if [[ "$path" == *.sh ]]; then
+        shellcheck_paths+=("$path")
+      fi
+    done <<< "$FLAKEBOX_GIT_LS_TEXT"
+
+    if [[ "${#shellcheck_paths[@]}" -ne 0 ]]; then
+      shellcheck --severity=warning "${shellcheck_paths[@]}"
+    fi
 }
 export -f check_shellcheck