draft-release.yml

# When we close a milestone, create a draft release
name: Draft Release
on:
  milestone:
    types: [closed]

permissions:
  issues: read
  pull-requests: read
  contents: write

jobs:
  sync:
    name: Create Release
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v4.0.2
        name: Run script
        with:
          github-token: ${{secrets.GITHUB_TOKEN}}
          script: |
            const milestone = context.payload.milestone;

            // Find issues and PRs for this milestone
            github.paginate(github.issues.listForRepo, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'all',
              milestone: milestone.number
            })
            .then((items) => {
              // Get just the issues and format into a section for the release notes
              const issues = items.filter(i => !i.pull_request);
              const issue_text = '### Issues Closed\n' +
                                issues.map(i => `* [Issue ${i.number}](${i.html_url}) - ${i.title}\n`)
                                .join('') + `\n${issues.length} issues were closed in this release.`;

              // Now do the same for the PRs
              const prs = items.filter(i => !!i.pull_request);
              const pr_text = '### Pull Requests Merged\n' +
                              prs.map(i => `* [PR ${i.number}](${i.html_url}) - ${i.title}, by @${i.user.login}\n`)
                              .join('') + `\n${prs.length} pull requests were closed in this release.`;

              // Add the list of people who contributed PRs
              const contrib_text = '### Contributors\n' +
                                  Array.from(new Set(items.map(i => '@' + i.user.login))).join(', ') +
                                  ' contributed code to this release.';

              // Assemble into the body of the release
              const body = [milestone.description, contrib_text, issue_text, pr_text].join('\n');

              // Allows us to optionally pass in a branch of if there's one specified in the
              // text of the milestone
              params = {
                owner: context.repo.owner,
                repo: context.repo.repo,
                tag_name: 'v' + milestone.title,
                name: milestone.title,
                draft: true,
                body: body,
                discussion_category_name: 'Announcements'
              };
              const match = milestone.description.match(/branch:\s*([^\s]+)/);
              if (!!match) {
                params.target_commitish = match[1];
                console.log('Found target branch:', params.target_commitish);
              }
              github.repos.createRelease(params);
            });