auto-merge-on-approval.yml

# ------------------------------------------------------------------------------
#  Auto Merge on Approval Workflow
#
#  Purpose: Automatically merge PRs once all approval and CI conditions pass.
#
#  Triggers: Pull‑request events, review submissions, and completed checks.
#
#  Maintainer: @mrz1836
#
#  Rules for Auto‑Merge:
#    • ≥1 approval review
#    • No requested reviewers remaining
#    • No "Changes Requested" reviews
#    • All required status checks pass:
#        - test (1.18.x, ubuntu-latest) (min version)
#        - test (1.23.x, ubuntu-latest) (-1 version)
#        - test (1.24.x, ubuntu-latest) (latest version)
#        - Analyze (go)
#    • Title must not contain "WIP"
#    • PR must not have the "work-in-progress" label
#    • PR must not be a draft
# ------------------------------------------------------------------------------

name: auto-merge-on-approval

on:
    pull_request:
        types:
          [opened, synchronize, reopened, ready_for_review, labeled, unlabeled, edited]
    pull_request_review:
        types: [submitted]
    check_suite:
        types: [completed]
    status: {}

# Cancel older runs of the same PR if a new commit is pushed
concurrency:
    group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
    cancel-in-progress: true

permissions:
    contents: read
    pull-requests: read

jobs:
    automerge:
        permissions:
            pull-requests: write

        runs-on: ubuntu-latest

        steps:
            - name: Attempt auto‑merge
              uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7
              with:
                  github-token: ${{ secrets.GITHUB_TOKEN }}
                  script: |
                      // core and github are already available in github-script

                      // ------------------------------------------------------------------
                      // Locate the pull request (handles pull_request, check_suite, status)
                      // ------------------------------------------------------------------
                      const owner = context.payload.repository.owner.login;
                      const repo = context.payload.repository.name;
                      let pr = context.payload.pull_request;
                      if (!pr) {
                        // check_suite/status → find PR by HEAD SHA
                        const sha = context.payload.check_suite?.head_sha || context.payload.sha;
                        if (sha) {
                          const { data: prs } = await github.rest.pulls.list({
                            owner,
                            repo,
                            head:  `${owner}:${sha}`,
                            state: 'open',
                          });
                          pr = prs[0];
                        }
                      }
                      if (!pr) {
                        core.info('PR not found (may be closed), skipping.');
                        return;
                      }

                      // ------------------------------------------------------------------
                      // Skip PRs authored by bots (Dependabot / Codecov / etc.)
                      // ------------------------------------------------------------------
                      //const botLogins = [
                      //  'dependabot[bot]',
                      //  'dependabot-preview[bot]',
                      //  'codecov[bot]',
                      //];
                      //if (botLogins.includes(pr.user.login)) {
                      //  core.info(`Skipping auto‑merge for bot‑authored PR (#${pr.number})`);
                      //  return;
                      //}

                      // ------------------------------------------------------------------
                      // Gather PR metadata
                      // ------------------------------------------------------------------
                      const prNumber = pr.number;
                      const title    = pr.title || '';
                      const labels   = pr.labels.map(l => l.name);
                      const isDraft  = pr.draft;

                      // Reviews
                      const { data: reviews } = await github.rest.pulls.listReviews({
                        owner,
                        repo,
                        pull_number: prNumber,
                      });
                      const approvals        = reviews.filter(r => r.state === 'APPROVED').length;
                      const changesRequested = reviews.filter(r => r.state === 'CHANGES_REQUESTED').length;

                      // Requested reviewers
                      const requestedReviewers = pr.requested_reviewers || [];

                      // Required checks
                      const requiredChecks = [
                        'test (1.18.x, ubuntu-latest)',
                        'test (1.23.x, ubuntu-latest)',
                        'test (1.24.x, ubuntu-latest)',
                        'Analyze (go)',
                      ];
                      const sha = pr.head.sha;
                      const { data: checks } = await github.rest.checks.listForRef({
                        owner,
                        repo,
                        ref: sha,
                      });
                      const checkRuns = checks.check_runs || [];
                      const checksPass = requiredChecks.every(name => {
                        const run = checkRuns.find(c => c.name === name);
                        return run && run.conclusion === 'success';
                      });

                      // WIP indicators
                      const titleHasWip = /wip/i.test(title);
                      const hasWipLabel = labels.includes('work-in-progress');

                      // ------------------------------------------------------------------
                      // Merge or explain why not
                      // ------------------------------------------------------------------
                      if (
                        approvals >= 1 &&
                        requestedReviewers.length === 0 &&
                        changesRequested === 0 &&
                        checksPass &&
                        !titleHasWip &&
                        !hasWipLabel &&
                        !isDraft
                      ) {
                        try {
                          await github.rest.pulls.merge({
                            owner,
                            repo,
                            pull_number: prNumber,
                            merge_method: 'merge',
                          });
                          console.log(`✅ Pull request #${prNumber} merged.`);
                        } catch (error) {
                          core.setFailed(`❌ Failed to merge PR #${prNumber}: ${error.message}`);
                        }
                      } else {
                        if (approvals < 1)           console.log('⏭  Less than 1 approval.');
                        if (requestedReviewers.length)
                                                     console.log('⏭  Still has requested reviewers.');
                        if (changesRequested)        console.log('⏭   "Changes Requested" reviews present.');
                        if (!checksPass) {
                          const failed = requiredChecks.filter(name => {
                            const run = checkRuns.find(c => c.name === name);
                            return !(run && run.conclusion === 'success');
                          });
                          console.log(`⏭  Required checks failed: ${failed.join(', ')}`);
                        }
                        if (titleHasWip)             console.log('⏭  Title contains  "WIP".');
                        if (hasWipLabel)             console.log('⏭  Has  "work-in-progress" label.');
                        if (isDraft)                 console.log('⏭  PR is a draft.');
                      }