Enhance release workflow and documentation for tag validation and release notes generation

- Added validation for accepted release tag formats in the release workflow.
- Implemented a step to generate release notes based on changes since the last tag.
- Updated README.md to include accepted tag formats for stable and prerelease versions.
- Adjusted archive naming convention for consistency in release artifacts.

.gitea/workflows/release.yaml

@@ -11,8 +11,33 @@ jobs:
     name: Build and publish release
     runs-on: ubuntu-latest
     steps:
+      - name: Validate tag and determine prerelease flag
+        id: release_meta
+        shell: bash
+        run: |
+          set -eu
+          tag="${{ github.ref_name }}"
+          # Allowed tags:
+          # - Stable:    1.2.3
+          # - Prerelease: 1.2.3-alpha1 | 1.2.3-beta1 | 1.2.3-rc1
+          if [[ "${tag}" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            echo "prerelease=false" >> "${GITHUB_OUTPUT}"
+          elif [[ "${tag}" =~ ^[0-9]+\.[0-9]+\.[0-9]+-(alpha|beta|rc)[0-9]+$ ]]; then
+            echo "prerelease=true" >> "${GITHUB_OUTPUT}"
+          else
+            echo "Invalid tag format: ${tag}"
+            echo "Expected one of:"
+            echo "  - 1.2.3"
+            echo "  - 1.2.3-alpha1"
+            echo "  - 1.2.3-beta1"
+            echo "  - 1.2.3-rc1"
+            exit 1
+          fi
+
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Setup Go
         uses: actions/setup-go@v5
@@ -62,7 +87,7 @@ jobs:
 
           for bin in dist/scratchbox-linux-*; do
             name="$(basename "${bin}")"
-            archive="scratchbox-${{ github.ref_name }}-${name}.tar.gz"
+            archive="scratchbox-${{ github.ref_name }}-${name#scratchbox-}.tar.gz"
             stage="release-packages/${name}"
 
             rm -rf "${stage}"
@@ -72,10 +97,40 @@ jobs:
             tar -C "${stage}" -czf "${archive}" .
           done
 
+      - name: Generate release notes
+        shell: bash
+        run: |
+          set -eu
+          current_tag="${{ github.ref_name }}"
+          prev_tag="$(git tag --sort=-creatordate | awk -v cur="${current_tag}" '$0 != cur { print; exit }')"
+
+          {
+            echo "## Release ${current_tag}"
+            echo
+            if [ -n "${prev_tag}" ]; then
+              echo "Changes since \`${prev_tag}\`:"
+              echo
+              git log --pretty='- %h %s' "${prev_tag}..${current_tag}"
+            else
+              echo "Changes in this release:"
+              echo
+              git log --pretty='- %h %s' "${current_tag}"
+            fi
+            echo
+            echo "## Artifacts"
+            echo
+            echo "- \`linux-amd64-default\`"
+            echo "- \`linux-amd64-static\`"
+            echo "- \`linux-arm64-default\`"
+            echo "- \`linux-arm64-static\`"
+          } > RELEASE_NOTES.md
+
       - name: Create release and upload archives
         uses: https://gitea.com/actions/gitea-release-action@v1
         with:
           tag_name: ${{ github.ref_name }}
           name: ${{ github.ref_name }}
+          prerelease: ${{ steps.release_meta.outputs.prerelease }}
+          body_path: RELEASE_NOTES.md
           files: |-
             scratchbox-${{ github.ref_name }}-linux-*.tar.gz

README.md

@@ -52,6 +52,11 @@ Create config files with the image (writes to mounted `./docker-config`):
 
 Tagged releases provide `.tar.gz` archives with prebuilt Linux binaries.
 
+Accepted release tag formats:
+
+- `1.2.3` (stable release)
+- `1.2.3-alpha1`, `1.2.3-beta1`, `1.2.3-rc1` (prerelease)
+
 Variant guide:
 
 | Variant | Recommended for | Notes |