Add automated CI workflow for releases

.github/workflows/release.yml

@@ -0,0 +1,111 @@
+name: Release on Version Change
+
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - 'nixfmt.cabal'
+
+jobs:
+  release-if-version-changed:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout main
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 2  # need previous commit for comparison
+
+      - name: Get version from nixfmt.cabal
+        id: get_version
+        run: |
+          CABAL_FILE="nixfmt.cabal"
+
+          # Extract the version
+          VERSION=$(grep -m1 "^version:" $CABAL_FILE | awk '{print $2}')
+          echo "Version found in cabal: $VERSION"
+
+          # Get previous version from last commit
+          PREV_VERSION=$(git show HEAD~1:"$CABAL_FILE" | grep -m1 "^version:" | awk '{print $2}' || echo "none")
+          echo "Previous version: $PREV_VERSION"
+
+          # Export for later steps
+          echo "version=$VERSION" >> $GITHUB_OUTPUT
+          echo "prev_version=$PREV_VERSION" >> $GITHUB_OUTPUT
+
+      - name: Check if version changed
+        id: compare
+        run: |
+          if [ "${{ steps.get_version.outputs.version }}" != "${{ steps.get_version.outputs.prev_version }}" ]; then
+            echo "version_changed=true" >> $GITHUB_ENV
+          echo "::notice ::✅ Version changed from ${{ steps.get_version.outputs.prev_version }} to ${{ steps.get_version.outputs.version }}"
+          else
+            echo "version_changed=false" >> $GITHUB_ENV
+          echo "::notice ::Version did not change skipping release."
+          fi
+      - name: Extract changelog section for current version
+        if: env.version_changed == 'true'
+        run: |
+          VERSION="${{ steps.get_version.outputs.version }}"
+          echo "Extracting changelog section for version $VERSION"
+
+          # Extract everything after the "## <version>" header until the next "## "
+          awk -v ver="$VERSION" '
+            $0 ~ "^##[[:space:]]+" ver {found=1; next}
+            found && /^##[[:space:]]+/ {exit}
+            found
+          ' CHANGELOG.md > RELEASE_NOTES.md
+
+          if [ ! -s RELEASE_NOTES.md ]; then
+            echo "::error ::⚠️ No changelog section found for version $VERSION"
+            echo "(Make sure you have a header like '## $VERSION -- YYYY-MM-DD')"
+            echo "- No notes will be attached to the release -"
+            echo "No changelog section found for version $VERSION." > RELEASE_NOTES.md
+          fi
+
+          echo "---- Extracted Changelog ----"
+          cat RELEASE_NOTES.md
+          echo "--------------------------"
+
+      - name: Setup Nix
+        if: env.version_changed == 'true'
+        uses: cachix/install-nix-action@v26
+
+      - name: Setup Cachix cache
+        if: env.version_changed == 'true'
+        uses: cachix/cachix-action@v14
+        with:
+          name: nixos-nixfmt
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Build static binary
+        if: env.version_changed == 'true'
+        run: |
+          nix build -L .#nixfmt-static
+          mkdir -p release
+          echo "artifact_path=result/bin/nixfmt" >> $GITHUB_ENV
+
+      - name: Create Git tag
+        if: env.version_changed == 'true'
+        run: |
+          VERSION="${{ steps.get_version.outputs.version }}"
+          TAG="v${VERSION}"
+
+          echo "Creating tag $TAG"
+
+          git config user.name "Github Actions"
+          git config user.email "[email protected]"
+          git tag -a "$TAG" -m "Release $TAG"
+          git push origin "$TAG"
+
+      - name: Create GitHub Release
+        if: env.version_changed == 'true'
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: "v${{ steps.get_version.outputs.version }}"
+          name: "v${{ steps.get_version.outputs.version }}"
+          body_path: RELEASE_NOTES.md
+          files: "${{ env.artifact_path }}"
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

MAINTENANCE.md

@@ -8,4 +8,4 @@ rather than the version from the cabalfile.
 - Bump the version in the [cabal file](./nixfmt.cabal)
 - Update the [changelog](./CHANGELOG.md) with the new version
 - Create a PR with the above changes and merge it
-- Create a [new GitHub release](https://github.com/NixOS/nixfmt/releases/new) with tag matching the version and set the release notes to this versions changelog
+- After a successful build, a [new GitHub release](https://github.com/NixOS/nixfmt/releases) will automatically be created, along with a tag matching the version, via a GitHub Actions workflow. Keep an eye on the process to ensure everything runs smoothly!