name: Conventional PR Title

# Squash-merge replaces the merge commit subject with the PR title, so
# enforcing Conventional Commits at the PR-title level is what actually gates
# the commits that land on the default branch. The local commit-msg hook
# (.githooks/commit-msg) is a best-effort assist; this workflow is the gate.
#
# See https://www.conventionalcommits.org/en/v1.0.0/

on:
  pull_request:
    types: [opened, edited, reopened, synchronize, labeled, unlabeled]

permissions:
  pull-requests: read

jobs:
  lint-pr-title:
    name: Validate PR title
    runs-on: ubuntu-latest
    steps:
      - name: Check title against Conventional Commits
        uses: amannn/action-semantic-pull-request@48f256284bd46cdaab1048c3721360e808335d50 # v6.1.1
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          # Must mirror the type list in .githooks/commit-msg.
          types: |
            feat
            fix
            docs
            style
            refactor
            perf
            test
            build
            ci
            chore
            revert
          requireScope: false
          subjectPattern: ^(?![A-Z]).+$
          subjectPatternError: |
            The subject "{subject}" must start with a lowercase character.
          # Allow merges/reverts that GitHub generates automatically.
          ignoreLabels: |
            ignore-semantic-pull-request