commit-msg.sh

#!/usr/bin/env bash
# Validate commit messages follow conventional commit format.
set -euo pipefail

SUBJECT=$(grep -v '^#' "$1" | sed '/^$/d' | head -n1)

# Skip merge commits, reverts, and empty messages
[[ "$SUBJECT" =~ ^Merge[[:space:]] ]] && exit 0
[[ "$SUBJECT" =~ ^Revert[[:space:]]\" ]] && exit 0
[[ -z "$SUBJECT" ]] && exit 0

TYPES="feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert"
[[ "$SUBJECT" =~ ^($TYPES)(\(.+\))?!?:[[:space:]].+ ]] && exit 0

cat >&2 <<'MSG'
ERROR: commit message must follow conventional commit format.

  <type>[optional scope][!]: <description>

Valid types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert

Examples:
  feat: add semantic release workflow
  fix(pty): handle zombie processes on macOS
  refactor!: drop deprecated --legacy flag
  chore(deps): bump tokio to 1.42
MSG
exit 1