release.yml

name: Release

on:
  workflow_dispatch:
    inputs:
      version:
        description: 'Release version (e.g., 1.3). Leave empty to auto-increment minor. Do not add `v` into version name as it is prepended automatically.'
        required: false
        type: string
      description:
        description: 'Custom release description (prepended before auto-generated changelog).'
        required: false
        type: string

jobs:
  release:
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
      - name: Validate branch
        id: branch
        run: |
          BRANCH="${{ github.ref_name }}"
          
          echo "Validating branch: ${BRANCH}"
          if [[ ! "$BRANCH" =~ ^release-([0-9]+)\.x$ ]]; then
            echo "::error::Must run on a release-X.x branch (e.g., release-1.x)"
            exit 1
          fi
          echo "major=${BASH_REMATCH[1]}" >> "$GITHUB_OUTPUT"

      - name: Checkout
        uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - name: Determine version
        id: version
        env:
          MAJOR: ${{ steps.branch.outputs.major }}
        run: |
          if [[ -n "${{ inputs.version }}" ]]; then
            VERSION="${{ inputs.version }}"
            if [[ ! "$VERSION" =~ ^${MAJOR}\.[0-9]+$ ]]; then
              echo "::error::Version $VERSION does not match branch major version $MAJOR"
              exit 1
            fi
          else
            LATEST=$(git tag -l "v${MAJOR}.*" --sort=-v:refname | head -n1)
            if [[ -z "$LATEST" ]]; then
              VERSION="${MAJOR}.0"
            else
              MINOR="${LATEST##*.}"
              VERSION="${MAJOR}.$((MINOR + 1))"
            fi
          fi
          TAG="v$VERSION"
          if git rev-parse "refs/tags/$TAG" &>/dev/null; then
            echo "::error::Tag $TAG already exists"
            exit 1
          fi
          echo "tag=$TAG" >> "$GITHUB_OUTPUT"
          echo "Releasing: $TAG"

      - name: Create and push tag
        env:
          TAG: ${{ steps.version.outputs.tag }}
        run: |
          git tag "$TAG"
          git push origin "$TAG"

      - name: Update floating major tag
        env:
          TAG: ${{ steps.version.outputs.tag }}
          MAJOR: ${{ steps.branch.outputs.major }}
        run: |
          git tag -f "v${MAJOR}" "$TAG"
          git push origin "v${MAJOR}" --force

      - name: Generate release notes and create release
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.version.outputs.tag }}
          MAJOR: ${{ steps.branch.outputs.major }}
        run: |
          PREV_TAG=$(git tag -l "v${MAJOR}.*" --sort=-v:refname | grep -v "^${TAG}$" | head -n1)

          API_ARGS=(-f tag_name="$TAG")
          if [[ -n "$PREV_TAG" ]]; then
            API_ARGS+=(-f previous_tag_name="$PREV_TAG")
          fi
          AUTO_NOTES=$(gh api repos/${{ github.repository }}/releases/generate-notes \
            "${API_ARGS[@]}" --jq '.body')

          DESCRIPTION="${{ inputs.description }}"
          if [[ -n "$DESCRIPTION" ]]; then
            printf '%s\n\n---\n\n%s' "$DESCRIPTION" "$AUTO_NOTES" > release-notes.md
          else
            echo "$AUTO_NOTES" > release-notes.md
          fi

          gh release create "$TAG" \
            --title "$TAG" \
            --notes-file release-notes.md