draft-release.yml

name: draft-release

on:
  workflow_dispatch:
    inputs:
      version_tag:
        description: Semantic version tag for next release. If not provided, it will be determined based on conventional commmit history.
        required: false
        type: string
        default: ''
  push:
    branches:
      - release-draft

env:
  GH_TOKEN: ${{ github.token }}
  BRANCH: release-draft

jobs:
  draft-release:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0 # required to include tags
      - uses: actions/setup-python@v4
        with:
          python-version: '3.11'
          cache: 'pip'
      - run: pip install cffconvert>=2.0.0 pyyaml

      - name: Get Date
        run: |
          echo "DATE=$(date +"%Y-%m-%d")" >> "$GITHUB_ENV"

      - name: Get current and next versions
        id: semver
        uses: ietf-tools/semver-action@v1
        with:
          token: ${{ github.token }}
          branch: ${{ github.ref_name }}

      - name: Set version variables
        shell: python {0}
        run: |
          import os
          import re
          import warnings

          convco_version = "${{ steps.semver.outputs.next }}"
          if "${{ github.event_name }}" == 'workflow_dispatch' and "${{ github.event.inputs.version_tag }}":
            next_version = "${{ github.event.inputs.version_tag }}"
            if next_version != convco_version:
              warnings.warn(f"Manual version ({next_version}) not equal to version determined by conventional commit history ({convco_version})")
          else:
            next_version = convco_version

          with open(os.getenv("GITHUB_ENV"), 'a') as out_env:
            out_env.write(f"NEXT_VERSION={next_version}\n")
            out_env.write(f"NEXT_STRICT={next_version.strip('v')}\n")
          current_version = "${{ steps.semver.outputs.current }}"

          # assert semantic version pattern
          semver_pattern = 'v(?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)\.(?P<patch>0|[1-9]\d*)(?:-(?P<prerelease>(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+(?P<buildmetadata>[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?'
          next_semver = re.match(semver_pattern, next_version)
          if not next_semver:
            raise ValueError(f"Tag {next_version} does not match semantic versioning guidelines")

          # assert next version is only 1 greater than current
          current_semver = re.match(semver_pattern, current_version)
          groups = ['major', 'minor', 'patch']
          greater = sum([next_semver.group(grp) > current_semver.group(grp) for grp in groups])
          equal = sum([next_semver.group(grp) == current_semver.group(grp) for grp in groups])
          if not (greater == 1 and equal == 2):
            raise ValueError(f"Next version must only increment one number at a time. Current version: {current_version}. Proposed next version: {next_version}")

      - name: Get release notes, update changelog & version file
        shell: python {0}
        run: |
          import os
          latest_version = "${{ steps.semver.outputs.current }}".strip('v')
          next_version = "${{ env.NEXT_STRICT }}"

          changelog_lines = list()
          next_release_lines = list()
          for_next = True
          with open("CHANGELOG.md", "r") as infile:
            for line in infile:
              if line.startswith('#') and 'development version' in line:
                line = line.replace('development version', next_version)
              elif latest_version in line:
                for_next = False

              changelog_lines.append(line)
              if for_next:
                next_release_lines.append(line)

          with open(".github/latest-release.md", "w") as outfile:
            outfile.writelines(next_release_lines)
          with open('CHANGELOG.md', 'w') as outfile:
            outfile.writelines(changelog_lines)
          with open("VERSION", "w") as outfile:
            outfile.write(f"{next_version}\n")

      - name: Update citation
        shell: python {0}
        run: |
          from cffconvert.cli.create_citation import create_citation
          from cffconvert.cli.validate_or_write_output import validate_or_write_output
          import yaml

          citation = create_citation('CITATION.cff', None)
          citation._implementation.cffobj['version'] = "${{ env.NEXT_VERSION }}"
          citation._implementation.cffobj['date-released'] = "${{ env.DATE }}"
          with open('CITATION.cff', 'w') as outfile:
            outfile.write(yaml.dump(citation._implementation.cffobj, sort_keys=False))

      - name: Commit & push to branch
        run: |
          git config --local user.name "github-actions[bot]"
          git config --local user.email "41898282+github-actions[bot]@users.noreply.github.com"

          git push origin --delete ${{ env.BRANCH }} || echo "No ${{ env.BRANCH }} branch to delete"
          git switch -c ${{ env.BRANCH }} || git switch ${{ env.BRANCH }}
          git merge --ff-only ${{ github.ref_name }}

          git add CITATION.cff CHANGELOG.md VERSION
          git commit -m 'chore: prepare release ${{ env.NEXT_VERSION }}'
          git push --set-upstream origin ${{ env.BRANCH }}

          echo "COMMIT_HASH=$(git rev-parse HEAD)" >> "$GITHUB_ENV"

      - name: Tag & draft release
        run: |
          gh release create ${{ env.NEXT_VERSION }} \
            --draft \
            --notes-file .github/latest-release.md \
            --target ${{ env.COMMIT_HASH }} \
            --title "${{ github.event.repository.name }} ${{ env.NEXT_STRICT }}"

      - name: Next steps
        run: |
          echo "Next steps: Take a look at the changes in the ${{ env.BRANCH }} branch and the release notes on the web. If everything is correct, publish the release. Otherwise, delete the release draft and cut the release manually."