Meta: Do not tag release without public changes (#427)

This is mostly a refactoring of our GitHub actions. The tag workflow and
script have been removed completely, since the release action will
implicitly create the release tag if it does not exit, yet. This makes
sure that we do not create a tag when there will be no release.

We have only one workflow now, which contains two jobs: one for
generating the changelog and one for creating the release.

The changelog job will generate the changelog and upload it as an
artifact if there are public changes. The release version, which
previously was determined in the tag script, is now determined within
this job, so that we can pass it to the release job.

The release job will run only if the changelog job was successful, i.e.
if there are public changes. It will create a tag and a GitHub release
with the given version number.

The workflow will run on the first day of every month for our regular
automatic monthly releases.
It will also run on every tag push, so that we still can create a
release manually if necessary. The release action will implicitly use
the existing tag for the release then.

Fixes #413
Closes #414

.github/scripts/tag.sh

@@ -1,21 +0,0 @@
-#!/bin/bash
-
-set -e
-
-head_tag=$(git describe --exact-match 2>/dev/null || true)
-
-git log --color=always --format="%C(auto)%h %s%d" | head
-
-if [[ ${head_tag} =~ [\d{2}\.\d{2}\.\d+] ]]
-then
-    echo "Version tag ${head_tag} already exists."
-else
-    git config --local user.email "github-actions@users.noreply.github.com"
-    git config --local user.name "github-actions"
-    version=$(date +'%y.%m.0')
-    git tag -a ${version} -m "Release ${version}"
-    git push origin ${version}
-    git log --color=always --format="%C(auto)%h %s%d" | head -1
-    echo "Pushed new tag:"
-    echo "${REPO_URL}/releases/tag/${version}"
-fi

.github/workflows/release.yaml

@@ -1,32 +1,78 @@
 name: Release
 
 on:
+  schedule:
+    # Run on every first day of the month
+    - cron: '0 0 1 * *'
   push:
     tags:
       - '**'
 
 jobs:
 
-  release:
+  changelog:
     runs-on: ubuntu-latest
     steps:
-
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Create Package
-        run: tar -czf forgit-${{github.ref_name}}.tar.gz --exclude LICENSE --exclude README.md *
-
       - name: Generate Changelog
         id: changelog
         run: .github/scripts/changelog.sh > CHANGELOG.md
+        # When the script returns with an error, it indicates that we don't have
+        # any public changes to be released. This is expected behavior, so we
+        # quit the workflow successfully in this case.
         continue-on-error: true
 
+      - name: Upload Changelog
+        uses: actions/upload-artifact@v4
+        if: steps.changelog.outcome == 'success'
+        with:
+          name: changelog
+          path: CHANGELOG.md
+
+      - name: Set version
+        id: set_version
+        if: steps.changelog.outcome == 'success'
+        # Set version depending on whether this is a regular monthly release or
+        # a custom release triggered by a tag push.
+        run: |
+          if [ "${{ github.event_name }}" == "push" ]; then
+            VERSION=${{ github.ref_name }}
+          else
+            VERSION=$(date +'%y.%m.0')
+          fi
+          echo "VERSION=$VERSION"
+          echo "VERSION=$VERSION" >> $GITHUB_OUTPUT
+
+    outputs:
+      changeLogOutcome: ${{ steps.changelog.outcome }}
+      version: ${{ steps.set_version.outputs.VERSION }}
+
+  release:
+    runs-on: ubuntu-latest
+    needs: changelog
+    if: needs.changelog.outputs.changeLogOutcome == 'success'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Download Changelog
+        uses: actions/download-artifact@v4
+        with:
+          name: changelog
+
+      - name: Create Package
+        run: tar -czf forgit-${{ needs.changelog.outputs.version }}.tar.gz --exclude LICENSE --exclude README.md *
+
       - name: Release
         uses: softprops/action-gh-release@v2
-        if: steps.changelog.outcome == 'success'
         with:
+          # The release action implicitly creates the tag if it does not exist.
+          tag_name: ${{ needs.changelog.outputs.version }}
           body_path: CHANGELOG.md
-          files: forgit-${{github.ref_name}}.tar.gz
+          files: forgit-${{ needs.changelog.outputs.version }}.tar.gz

.github/workflows/tag.yaml

@@ -1,28 +0,0 @@
-name: Tag
-
-on:
-  schedule:
-    # Run on every first day of the month
-    - cron: '0 0 1 * *'
-
-jobs:
-
-  tag:
-    runs-on: ubuntu-latest
-    steps:
-
-      - name: Checkout
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-          # The COMMIT_KEY secret contains a private SSH key. The associated public key
-          # has been added as a deploy key in the GitHub project. See:
-          # https://docs.github.com/en/developers/overview/managing-deploy-keys#deploy-keys
-          # This is necessary to make commits done by github-actions able to trigger
-          # further github-actions. See: https://stackoverflow.com/q/60418323/3018229.
-          ssh-key: "${{secrets.COMMIT_KEY}}"
-
-      - name: Create Tag
-        run: .github/scripts/tag.sh
-        env:
-          REPO_URL: ${{github.server_url}}/${{github.repository}}