pr-format-verification.yml

name: PR format verification

on:
  pull_request:
    branches:
      - main
    types:
      # By default, a workflow only runs when a pull_request event's activity type is opened, synchronize, or reopened.
      - opened
      - synchronize
      - edited
      - reopened

defaults:
  run:
    shell: bash -euo pipefail {0}

jobs:
  pr-format-verification:
    name: Check PR title
    # Only run the job if the PR is not created by dependabot.
    # We still want dependabot PRs to go through, they contain important security updates,
    # and there's no good way of getting dependabot to conform to our PR format
    if: github.actor != 'dependabot[bot]'
    runs-on: ubuntu-22.04
    steps:
      - name: Verify PR Title
        env:
          ON_FAILURE: |
            PR title must be prefixed with component names (e.g., "vm-builder: ..." or "agent/subsystem,neonvm: ...") OR body must contain the string "<!-- affects all -->"

            Some common component names:
             * "agent" (the autoscaler-agent)
             * "plugin" (the scheduler)
             * "neonvm-controller" / "neonvm-runner" / "vm-builder" (individual parts of "neonvm")
             * "neonvm" (when the PR affects most neonvm-related components)
             * "ci" / "CI" - depending on your capitalization

            Some common subsystems:
             * "agent/billing" (generation of billing events in the autoscaler-agent)
             * "agent/core" (core scaling algorithm in the autoscaler-agent)
             * "plugin/trans" (core resource logic in the scheduler plugin)
             * "ci/lint" (lints workflow in CI)

            Check recent PRs for examples: https://github.com/neondatabase/autoscaling/pulls?q=is%3Apr+is%3Aclosed
        run: |
          title="$(jq --raw-output .pull_request.title "$GITHUB_EVENT_PATH")"
          body="$(jq --raw-output .pull_request.body "$GITHUB_EVENT_PATH")"

          # If the PR body contains the magic string, ignore it.
          if grep -q '<!-- affects all -->' <(echo "$body") >/dev/null ; then
              exit 0
          fi

          # If the title looks like 'Revert "..."', then give it a pass.
          if grep -q '^Revert "' <(echo "$title") >/dev/null ; then
              exit 0
          fi

          # Check that title matches the regex:
          WORD='[a-z0-9-.]+'
          COMPONENT="$WORD(/$WORD)*" # one or more '/'-separated words
          TITLE_PREFIX="$COMPONENT(,$COMPONENT)*" # one or more ','-separated components
          TITLE_MSG='.+' # Any non-empty message.
          TITLE_REGEX="^$TITLE_PREFIX: $TITLE_MSG\$"

          if ! grep -qiP "$TITLE_REGEX" <(echo "$title") >/dev/null ; then
              echo "$ON_FAILURE" >/dev/stderr
              exit 1
          fi