release.yml

name: Release

on:
  push:
    tags:
      - 'v*'
  workflow_dispatch:
    inputs:
      version:
        description: 'Version to release (e.g. 1.0.0 or 1.0.0-rc.2). The leading "v" is added automatically.'
        required: true
        type: string

permissions:
  contents: write

env:
  PACKAGE_PATH: .
  CHANGELOG_PATH: CHANGELOG.md

jobs:
  release:
    runs-on: ubuntu-latest

    steps:
      - name: Determine version
        id: version
        run: |
          set -euo pipefail
          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
            VERSION="${{ inputs.version }}"
          else
            VERSION="${GITHUB_REF_NAME}"
          fi
          VERSION="${VERSION#v}"
          if [[ ! "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.-]+)?$ ]]; then
            echo "::error::Version '$VERSION' is not a valid SemVer string."
            exit 1
          fi
          TAG="v$VERSION"
          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
          echo "tag=$TAG" >> "$GITHUB_OUTPUT"
          if [[ "$VERSION" == *-* ]]; then
            echo "prerelease=true" >> "$GITHUB_OUTPUT"
          else
            echo "prerelease=false" >> "$GITHUB_OUTPUT"
          fi
          echo "Releasing $TAG"

      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Configure git
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

      - name: Check tag does not already exist
        if: github.event_name == 'workflow_dispatch'
        run: |
          set -euo pipefail
          TAG="${{ steps.version.outputs.tag }}"
          if git rev-parse --verify --quiet "refs/tags/$TAG" >/dev/null; then
            echo "::error::Tag $TAG already exists locally. Delete it or pick another version."
            exit 1
          fi
          if git ls-remote --exit-code --tags origin "$TAG" >/dev/null 2>&1; then
            echo "::error::Tag $TAG already exists on origin."
            exit 1
          fi

      - name: Validate package.json version
        run: |
          set -euo pipefail
          VERSION="${{ steps.version.outputs.version }}"
          PKG_VERSION=$(jq -r .version "$PACKAGE_PATH/package.json")
          if [[ "$PKG_VERSION" != "$VERSION" ]]; then
            echo "::error file=$PACKAGE_PATH/package.json::package.json version ($PKG_VERSION) does not match release version ($VERSION). Bump it before tagging."
            exit 1
          fi
          echo "package.json version matches: $PKG_VERSION"

      - name: Extract CHANGELOG section
        id: changelog
        run: |
          set -euo pipefail
          VERSION="${{ steps.version.outputs.version }}"
          NOTES=$(awk -v ver="$VERSION" '
            BEGIN { capture = 0 }
            /^## \[/ {
              if (capture) { exit }
              if ($0 ~ "^## \\[" ver "\\]([^0-9A-Za-z.-]|$)") { capture = 1; next }
            }
            capture { print }
          ' "$CHANGELOG_PATH")

          if [[ -z "$(echo "$NOTES" | tr -d '[:space:]')" ]]; then
            echo "::error file=$CHANGELOG_PATH::No CHANGELOG section found for version $VERSION. Add a '## [$VERSION] — YYYY-MM-DD' heading before releasing."
            exit 1
          fi

          {
            echo "notes<<__CHANGELOG_EOF__"
            echo "$NOTES"
            echo "__CHANGELOG_EOF__"
          } >> "$GITHUB_OUTPUT"

          echo "CHANGELOG section for $VERSION extracted ($(echo "$NOTES" | wc -l) lines)."

      - name: Create and push release tag
        if: github.event_name == 'workflow_dispatch'
        run: |
          set -euo pipefail
          TAG="${{ steps.version.outputs.tag }}"
          git tag -a "$TAG" -m "Release $TAG"
          git push origin "$TAG"

      - name: Checkout release tag
        run: |
          set -euo pipefail
          git fetch origin "refs/tags/${{ steps.version.outputs.tag }}:refs/tags/${{ steps.version.outputs.tag }}" || true
          git checkout "${{ steps.version.outputs.tag }}"

      - name: Publish UPM tag and branch
        run: |
          set -euo pipefail
          VERSION="${{ steps.version.outputs.version }}"
          TAG="${{ steps.version.outputs.tag }}"
          PRERELEASE="${{ steps.version.outputs.prerelease }}"
          UPM_TAG="upm/$VERSION"

          if git ls-remote --exit-code --tags origin "$UPM_TAG" >/dev/null 2>&1; then
            echo "::error::Tag $UPM_TAG already exists on origin. Refusing to overwrite a published UPM tag."
            exit 1
          fi

          # Build a tree containing only the Unity package contents — strip
          # repo-only paths so consumers don't pull workflows, CI configs, etc.
          UPM_INDEX=$(mktemp)
          trap 'rm -f "$UPM_INDEX"' EXIT
          export GIT_INDEX_FILE="$UPM_INDEX"
          git read-tree "$TAG"
          git rm -r --cached --quiet --ignore-unmatch .github CLAUDE.md CLAUDE.md.meta .gitignore .gitignore.meta
          TREE=$(git write-tree)
          unset GIT_INDEX_FILE
          PARENT=$(git rev-parse "$TAG^{commit}")
          COMMIT=$(git commit-tree "$TREE" -p "$PARENT" -m "UPM release $VERSION")

          # Move the appropriate upm branch forward:
          # pre-releases → upm-preview, stable releases → upm.
          if [[ "$PRERELEASE" == "true" ]]; then
            UPM_BRANCH="upm-preview"
          else
            UPM_BRANCH="upm"
          fi
          git push --force origin "$COMMIT:refs/heads/$UPM_BRANCH"

          # Immutable per-version tag for users who pin to a specific release.
          git tag "$UPM_TAG" "$COMMIT"
          git push origin "$UPM_TAG"

          echo "Published $UPM_TAG and updated $UPM_BRANCH branch."

      - name: Create GitHub release
        uses: softprops/action-gh-release@v2
        with:
          tag_name: ${{ steps.version.outputs.tag }}
          name: ${{ steps.version.outputs.tag }}
          body: ${{ steps.changelog.outputs.notes }}
          prerelease: ${{ steps.version.outputs.prerelease == 'true' }}