github-release.yml

name: GitHub Release
run-name: GH Release from ${{ inputs.ref }}

# Tags the chosen ref with `v<version>` (where version comes from
# gradle/libs.versions.toml) and creates a GitHub Release that combines:
#   1. The hand-written changelog at `changelogs/<version>.md`
#   2. GitHub's auto-generated "What's Changed" section between the previous
#      v-tag and this one.
#
# Typical flow:
#   1. Bump `modo = "X.Y.Z"` in gradle/libs.versions.toml, commit, merge to dev.
#   2. Publish to Maven Central via the `Publish` workflow (separate concern).
#   3. Run this workflow with ref = dev (or release branch). Done.
#
# Pre-conditions checked at runtime:
#   - `changelogs/<version>.md` exists.
#   - Either the `v<version>` tag does not exist yet, or it exists but no
#     GitHub release has been created for it yet (retry-friendly).
#
# Versions containing `-` (e.g. `0.12.0-rc1`) are marked as pre-release.

on:
  workflow_dispatch:
    inputs:
      ref:
        description: "Git ref to release (branch, tag, or commit SHA)"
        required: true
        default: "dev"

permissions:
  contents: write

jobs:
  release:
    runs-on: ubuntu-latest
    timeout-minutes: 10

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          ref: ${{ inputs.ref }}
          fetch-depth: 0

      - name: Resolve version and changelog
        id: meta
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          VERSION=$(awk -F'"' '/^modo[[:space:]]*=/ {print $2; exit}' gradle/libs.versions.toml)
          if [ -z "$VERSION" ]; then
            echo "::error::Could not read 'modo' version from gradle/libs.versions.toml"
            exit 1
          fi
          TAG="v$VERSION"
          CHANGELOG="changelogs/${VERSION}.md"
          if [ ! -f "$CHANGELOG" ]; then
            echo "::error::Changelog not found: $CHANGELOG"
            exit 1
          fi

          # Retry-friendly: allow re-run if tag was created but release wasn't.
          # Fail only if both already exist.
          if git rev-parse "refs/tags/$TAG" >/dev/null 2>&1; then
            if gh release view "$TAG" >/dev/null 2>&1; then
              echo "::error::Release $TAG already exists. Bump version in libs.versions.toml."
              exit 1
            fi
            CREATE_TAG=false
            echo "Tag $TAG already exists; will reuse and only create the release."
          else
            CREATE_TAG=true
          fi

          {
            echo "tag=$TAG"
            echo "version=$VERSION"
            echo "changelog=$CHANGELOG"
            echo "create_tag=$CREATE_TAG"
            if [[ "$VERSION" == *-* ]]; then
              echo "prerelease=true"
            else
              echo "prerelease=false"
            fi
          } >> "$GITHUB_OUTPUT"

      - name: Create and push tag
        if: steps.meta.outputs.create_tag == 'true'
        env:
          TAG: ${{ steps.meta.outputs.tag }}
        run: |
          # Identity recommended by actions/checkout README:
          # https://github.com/actions/checkout#push-a-commit-using-the-built-in-token
          # Email format is {user.id}+{user.login}@users.noreply.github.com.
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git tag -a "$TAG" -m "$TAG"
          git push origin "$TAG"

      - name: Resolve previous tag
        id: prev
        env:
          TAG: ${{ steps.meta.outputs.tag }}
        run: |
          PREV=$(git tag --list 'v*' --sort=-v:refname \
            | grep -v "^${TAG}$" \
            | head -n 1 || true)
          echo "tag=$PREV" >> "$GITHUB_OUTPUT"

      - name: Compose release notes
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.meta.outputs.tag }}
          PREV: ${{ steps.prev.outputs.tag }}
          CHANGELOG: ${{ steps.meta.outputs.changelog }}
        run: |
          if [ -n "$PREV" ]; then
            AUTO=$(gh api -X POST "/repos/$GITHUB_REPOSITORY/releases/generate-notes" \
              -f tag_name="$TAG" \
              -f previous_tag_name="$PREV" \
              -q .body)
          else
            AUTO=$(gh api -X POST "/repos/$GITHUB_REPOSITORY/releases/generate-notes" \
              -f tag_name="$TAG" \
              -q .body)
          fi
          {
            cat "$CHANGELOG"
            echo
            echo "---"
            echo
            echo "$AUTO"
          } > /tmp/notes.md

      - name: Create release
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.meta.outputs.tag }}
          PRERELEASE: ${{ steps.meta.outputs.prerelease }}
        run: |
          ARGS=( --title "$TAG" --notes-file /tmp/notes.md )
          if [ "$PRERELEASE" = "true" ]; then
            ARGS+=( --prerelease )
          fi
          gh release create "$TAG" "${ARGS[@]}"
          echo "Released **$TAG**" >> "$GITHUB_STEP_SUMMARY"