github-release.yml

# Hand-maintained (like benchmarks.yml and update-readme-version.yml) — NOT
# generated by sbt githubWorkflowGenerate; do not add it to the sbt-typelevel
# config.
#
# Follow-up to a successful release: when the tag build of "Continuous
# Integration" (which publishes to Maven Central) completes green, create the
# GitHub Release for that tag. The body is the tag's `## [x.y.z]` section from
# CHANGELOG.md — the curated headline — with GitHub's auto-generated notes
# (PR list + contributors) appended. A missing changelog section FAILS the
# run on purpose: cutting the section is part of releasing. If the release
# already exists (e.g. created by hand before CI finished), the run
# short-circuits green BEFORE the changelog gate — its job is already done.
# `workflow_dispatch` backfills a release for any existing tag.

name: GitHub Release

on:
  workflow_run:
    workflows: ["Continuous Integration"]
    types: [completed]
  workflow_dispatch:
    inputs:
      tag:
        description: "Existing v* tag to (re)create the release for"
        required: true
        type: string

permissions:
  contents: write

concurrency:
  group: github-release
  cancel-in-progress: false

jobs:
  create-release:
    runs-on: ubuntu-22.04
    # workflow_run fires for every CI completion; act only on a SUCCESSFUL
    # tag build (head_branch is the tag name for tag-triggered runs).
    if: >-
      github.event_name == 'workflow_dispatch' ||
      (github.event.workflow_run.conclusion == 'success' &&
       startsWith(github.event.workflow_run.head_branch, 'v'))
    steps:
      - name: Resolve tag
        id: tag
        env:
          EVENT_NAME: ${{ github.event_name }}
          INPUT_TAG: ${{ inputs.tag }}
          HEAD_BRANCH: ${{ github.event.workflow_run.head_branch }}
        run: |
          if [ "$EVENT_NAME" = "workflow_dispatch" ]; then
            TAG="$INPUT_TAG"
          else
            TAG="$HEAD_BRANCH"
          fi
          # Final releases only — no GitHub Release for RCs/milestones.
          if ! echo "$TAG" | grep -Eq '^v[0-9]+\.[0-9]+\.[0-9]+$'; then
            echo "Not a final release tag: $TAG — skipping."
            echo "tag=" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          echo "tag=$TAG" >> "$GITHUB_OUTPUT"

      # The release may already exist (manual creation, previous backfill).
      # Detect it BEFORE the changelog gate: the workflow's job is done, so
      # exit green instead of failing on a section the frozen tag can't grow.
      - name: Check for an existing release
        id: existing
        if: steps.tag.outputs.tag != ''
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.tag.outputs.tag }}
        run: |
          if gh release view "$TAG" --repo "$GITHUB_REPOSITORY" > /dev/null 2>&1; then
            echo "Release $TAG already exists — leaving it untouched."
            echo "exists=true" >> "$GITHUB_OUTPUT"
          else
            echo "exists=false" >> "$GITHUB_OUTPUT"
          fi

      - uses: actions/checkout@v7
        if: steps.tag.outputs.tag != '' && steps.existing.outputs.exists != 'true'
        with:
          ref: ${{ steps.tag.outputs.tag }}

      - name: Extract the tag's CHANGELOG section
        if: steps.tag.outputs.tag != '' && steps.existing.outputs.exists != 'true'
        env:
          TAG: ${{ steps.tag.outputs.tag }}
        run: |
          VERSION="${TAG#v}"
          awk -v ver="$VERSION" '
            $0 ~ "^## \\[" ver "\\]" { hit = 1; next }
            hit && /^## \[/          { exit }
            hit                      { print }
          ' CHANGELOG.md > release-body.md
          if ! grep -q '[^[:space:]]' release-body.md; then
            echo "::error::CHANGELOG.md has no '## [$VERSION]' section — cut one before releasing."
            exit 1
          fi
          echo "--- release body ---"; cat release-body.md

      - name: Create the release
        if: steps.tag.outputs.tag != '' && steps.existing.outputs.exists != 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          TAG: ${{ steps.tag.outputs.tag }}
        run: |
          # Race guard: the release may have appeared since the check above.
          if gh release view "$TAG" --repo "$GITHUB_REPOSITORY" > /dev/null 2>&1; then
            echo "Release $TAG already exists — leaving it untouched."
            exit 0
          fi
          gh release create "$TAG" \
            --repo "$GITHUB_REPOSITORY" \
            --title "$TAG" \
            --verify-tag \
            --notes-file release-body.md \
            --generate-notes