dependabotautomerge.yml

name: Dependabot auto-merge
on:
  pull_request_target:
    types: [opened, reopened, synchronize, ready_for_review]
  workflow_dispatch:
  schedule:
    - cron: '17 * * * *'

permissions:
  contents: write
  pull-requests: write

jobs:
  dependabot:
    runs-on: ubuntu-latest
    if: ${{ github.event_name == 'pull_request_target' && github.actor == 'dependabot[bot]' && github.event.pull_request.draft == false }}
    steps:
      - name: Enable auto-merge for Dependabot PRs
        uses: peter-evans/enable-pull-request-automerge@v3
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          pull-request-number: ${{ github.event.pull_request.number }}
          merge-method: merge

  dependabot-backfill:
    runs-on: ubuntu-latest
    if: ${{ github.event_name != 'pull_request_target' }}
    steps:
      - name: Enable auto-merge on all open Dependabot PRs
        uses: actions/github-script@v9
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const {owner, repo} = context.repo;
            const pulls = await github.paginate(github.rest.pulls.list, {
              owner,
              repo,
              state: 'open',
              per_page: 100
            });

            const dependabotPRs = pulls.filter((pr) => pr.user?.login === 'dependabot[bot]' && !pr.draft);
            core.info(`Found ${dependabotPRs.length} open Dependabot PR(s).`);

            for (const pr of dependabotPRs) {
              try {
                await github.graphql(
                  `mutation EnableAutoMerge($pullRequestId: ID!) {
                    enablePullRequestAutoMerge(input: {pullRequestId: $pullRequestId, mergeMethod: MERGE}) {
                      pullRequest { number }
                    }
                  }`,
                  { pullRequestId: pr.node_id }
                );
                core.info(`Enabled auto-merge for #${pr.number}`);
              } catch (error) {
                core.warning(`Could not enable auto-merge for #${pr.number}: ${error.message}`);
              }
            }