auto-merge-on-release.yml

name: Auto-merge reusable workflow

on:
  workflow_call:
    inputs:
      head_branch:
        description: 'Branch name to find PR for'
        required: false
        type: string

permissions:
  contents: write
  pull-requests: write

jobs:
  auto-merge:
    runs-on: ubuntu-latest
    steps:
      - name: Auto-merge matching PR
        uses: actions/github-script@v8
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            // Use the provided input; caller should supply `head_branch` when invoking.
            const head_branch = "${{ inputs.head_branch }}";
            const owner = context.repo.owner;
            const repo = context.repo.repo;

            if (!head_branch) {
              core.info('No head_branch provided; nothing to do.');
              return;
            }

            core.info(`Auto-merge triggered for branch: ${head_branch}`);

            const prs = await github.rest.pulls.list({
              owner,
              repo,
              head: `${owner}:${head_branch}`,
              state: 'open',
            });

            if (!prs.data || prs.data.length === 0) {
              core.info(`No open pull request found for branch ${head_branch}`);
              return;
            }

            const pr = prs.data[0];

            if (pr.draft) {
              core.info(`Pull request #${pr.number} is a draft; skipping merge.`);
              return;
            }

            try {
              const res = await github.rest.pulls.merge({
                owner,
                repo,
                pull_number: pr.number,
                merge_method: 'merge',
                commit_title: head_branch,
                commit_message: '',
              });

              if (res.data.merged) {
                core.info(`Successfully merged PR #${pr.number} (branch ${head_branch}).`);
              } else {
                core.info(`Merge attempt returned: ${JSON.stringify(res.data)}`);
              }
            } catch (err) {
              core.setFailed(`Failed to merge PR #${pr.number}: ${err}`);
            }

      - name: Done
        run: echo "auto-merge finished"