release.yml

name: release

on:
  push:
    branches: [main]
    paths:
      - changelogs/**
  workflow_dispatch:
    inputs:
      dry_run:
        description: "Parse changelogs/ and print the release notes, but skip tag/release/discussion creation."
        type: boolean
        default: true

permissions:
  contents: write
  discussions: write

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: false

jobs:
  release:
    name: Cut release from changelogs
    runs-on: ubuntu-latest
    env:
      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - uses: actions/checkout@v7
        with:
          fetch-depth: 0

      - name: Select changelog and parse release notes
        id: parse
        run: |
          set -euo pipefail

          version_file_re='^changelogs/v[0-9]+\.[0-9]+\.[0-9]+\.md$'
          header_re='^# (v[0-9]+\.[0-9]+\.[0-9]+) - ([0-9]{4}-[0-9]{2}-[0-9]{2})$'

          candidates_file=$(mktemp)
          trap 'rm -f "$candidates_file"' EXIT

          if [[ "${GITHUB_EVENT_NAME}" == "push" ]]; then
            before="${GITHUB_EVENT_BEFORE:-}"
            if [[ -z "$before" || "$before" =~ ^0+$ ]]; then
              before="$(git rev-parse "${GITHUB_SHA}^" 2>/dev/null || true)"
            fi

            if [[ -n "$before" ]] && git cat-file -e "${before}^{commit}" 2>/dev/null; then
              git diff --name-only --diff-filter=AM "$before" "$GITHUB_SHA" -- changelogs/ \
                | grep -E "$version_file_re" > "$candidates_file" || true
            else
              # First commit / shallow history fallback: consider version files present at HEAD.
              git ls-files 'changelogs/v*.md' | grep -E "$version_file_re" > "$candidates_file" || true
            fi
          else
            # workflow_dispatch: consider every versioned changelog.
            git ls-files 'changelogs/v*.md' | grep -E "$version_file_re" > "$candidates_file" || true
          fi

          if [[ ! -s "$candidates_file" ]]; then
            echo "No versioned changelog candidates; nothing to do."
            echo "skip=true" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          selected=""
          selected_version=""
          while IFS= read -r file; do
            [[ -z "$file" || ! -f "$file" ]] && continue
            version="$(basename "$file" .md)"
            if git rev-parse --verify --quiet "refs/tags/${version}" >/dev/null; then
              echo "Skipping ${file}: tag ${version} already exists."
              continue
            fi

            header="$(awk 'NF { print; exit }' "$file")"
            if [[ ! "$header" =~ $header_re ]]; then
              echo "::error::${file}: first non-empty line must be '# ${version} - YYYY-MM-DD' (got: ${header})"
              exit 1
            fi
            header_version="${BASH_REMATCH[1]}"
            if [[ "$header_version" != "$version" ]]; then
              echo "::error::${file}: header version ${header_version} does not match filename ${version}"
              exit 1
            fi

            if [[ -z "$selected_version" ]] || \
               printf '%s\n' "$selected_version" "$version" | sort -V | tail -n1 | grep -qx "$version"; then
              selected="$file"
              selected_version="$version"
            fi
          done < "$candidates_file"

          if [[ -z "$selected" ]]; then
            echo "All candidate changelog versions are already tagged; nothing to do."
            echo "skip=true" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          version="$selected_version"
          echo "Selected ${selected} for release ${version}"

          # Body after the H1 title; keep in-file ## / ### section headings as release notes.
          awk '
            /^# / && !started { next }
            /^$/ && !started { next }
            { started = 1; buf = buf $0 "\n"; if (NF) final = buf }
            END { printf "%s", final }
          ' "$selected" > release-notes.md

          if [[ ! -s release-notes.md ]]; then
            echo "Extracted release notes from ${selected} are empty; refusing to publish."
            exit 1
          fi

          prev=$(git tag --list 'v*' --sort=-v:refname | head -n 1 || true)
          if [[ -n "${prev}" ]]; then
            shas_file=$(mktemp)
            prs_file=$(mktemp)
            if ! gh api "repos/${GITHUB_REPOSITORY}/compare/${prev}...${GITHUB_SHA}" \
                  --jq '.commits[].sha' > "$shas_file"; then
              echo "::warning::compare ${prev}...${GITHUB_SHA} failed; Pull Requests section will be incomplete"
            fi

            while IFS= read -r sha; do
              [[ -z "$sha" ]] && continue
              if ! gh api "repos/${GITHUB_REPOSITORY}/commits/${sha}/pulls" \
                    --jq '.[] | select(.merged_at != null) | "\(.number)\t\(.title)\t\(.user.login)"' \
                    >> "$prs_file"; then
                echo "::warning::PR lookup failed for ${sha}; release notes may be missing entries"
              fi
            done < "$shas_file"
            rm -f "$shas_file"

            if [[ -s "$prs_file" ]]; then
              printf '\n## 🔀 Pull Requests\n\n' >> release-notes.md
              awk -F'\t' '!seen[$1]++ { printf "- #%s %s by @%s\n", $1, $2, $3 }' \
                "$prs_file" >> release-notes.md
            fi
            rm -f "$prs_file"

            printf '\n**Full Changelog**: https://github.com/%s/compare/%s...%s\n' \
              "${GITHUB_REPOSITORY}" "${prev}" "${version}" >> release-notes.md
          fi

          echo "version=${version}" >> "$GITHUB_OUTPUT"
          echo "changelog=${selected}" >> "$GITHUB_OUTPUT"
          echo "skip=false" >> "$GITHUB_OUTPUT"

      - name: Dry-run preview
        if: steps.parse.outputs.skip != 'true' && github.event.inputs.dry_run == 'true'
        run: |
          echo "::group::Would publish ${{ steps.parse.outputs.version }}"
          echo "Changelog file:     ${{ steps.parse.outputs.changelog }}"
          echo "Target SHA:         ${{ github.sha }}"
          echo "Tag / title:        ${{ steps.parse.outputs.version }}"
          echo "Discussion category: Announcements"
          echo "----- release-notes.md -----"
          cat release-notes.md
          echo "----- end -----"
          echo "::endgroup::"
          echo "Dry run: no tag, no release, no discussion created."

      - name: Create GitHub release and announcement
        if: steps.parse.outputs.skip != 'true' && github.event.inputs.dry_run != 'true'
        run: |
          set -euo pipefail
          gh release create "${{ steps.parse.outputs.version }}" \
            --target "${{ github.sha }}" \
            --title "${{ steps.parse.outputs.version }}" \
            --notes-file release-notes.md \
            --discussion-category "Announcements" \
            --verify-tag=false