Stable per-branch SNAPSHOTs on CI (git-versioning)

me.qoomon.git-versioning v6.4.4 intermittently fails to detect the
branch on GitHub Actions runners and falls back to the rev clause,
producing the static gradle.properties version (2.0.0-rc5) instead of
<branch-slug>-SNAPSHOT. The failure is per-workflow-run, not per-
branch — same SHA, different runs, different results.

Root cause: actions/checkout leaves HEAD detached and only creates
refs/remotes/origin/<branch>; the plugin's heuristic sometimes picks
up the branch via the remote ref and sometimes doesn't.

Fix: after each checkout, materialise refs/heads/<branch> with
`git update-ref` pointing at HEAD. Deterministic, idempotent, and lets
git-versioning find the branch the same way it does locally.

Applied to all three workflows that invoke gradle (build-artifacts,
gradle-build's publish-gh-packages job, gh-pages). Also adds the
missing `fetch-depth: 0` to gh-pages.yml so the branch ref is actually
present.

Stable per-branch SNAPSHOTs are needed because integration tests
publish to and consume from build/maven-repo under the derived
coordinate; if it drifts to 2.0.0-rc5 we collide with the upcoming
release version and can't reliably exercise the branch's actual code.

Author: ascheman

.github/workflows/build-artifacts.yml

@@ -31,6 +31,26 @@ jobs:
           # and the plugin falls back to gradle.properties' static version.
           fetch-depth: 0
 
+      - name: Create local branch ref for git-versioning
+        # actions/checkout leaves HEAD detached and only creates refs/remotes/origin/<branch>.
+        # me.qoomon.git-versioning v6.4.4 sometimes finds the branch via the remote ref and
+        # sometimes falls back to the rev clause, producing 2.0.0-rc5 instead of
+        # <branch-slug>-SNAPSHOT — non-deterministic across workflow runs on the same SHA.
+        # Materialising refs/heads/<branch> ourselves makes detection reliable.
+        shell: bash
+        run: |
+          BRANCH="${GITHUB_HEAD_REF:-$GITHUB_REF_NAME}"
+          if [[ -z "$BRANCH" || "$BRANCH" == "HEAD" ]]; then
+            echo "::notice::No branch name; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          if [[ -z "$GITHUB_HEAD_REF" && "$GITHUB_REF" == refs/tags/* ]]; then
+            echo "::notice::Tag push; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          git update-ref "refs/heads/$BRANCH" HEAD
+          echo "::notice::Materialised refs/heads/$BRANCH at $(git rev-parse --short HEAD)"
+
       - name: Setup Java
         uses: actions/setup-java@v5
         with:

.github/workflows/gh-pages.yml

@@ -51,6 +51,28 @@ jobs:
 
       - name: Check out
         uses: actions/checkout@v5
+        with:
+          # Needed for git-versioning to derive the branch-slug-SNAPSHOT version
+          # when generate-pages calls `./gradlew -q printVersion`.
+          fetch-depth: 0
+
+      - name: Create local branch ref for git-versioning
+        # See build-artifacts.yml — without this, git-versioning intermittently falls back
+        # to gradle.properties' static version, and generate-pages then asks self-check
+        # for the wrong coordinate.
+        shell: bash
+        run: |
+          BRANCH="${GITHUB_HEAD_REF:-$GITHUB_REF_NAME}"
+          if [[ -z "$BRANCH" || "$BRANCH" == "HEAD" ]]; then
+            echo "::notice::No branch name; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          if [[ -z "$GITHUB_HEAD_REF" && "$GITHUB_REF" == refs/tags/* ]]; then
+            echo "::notice::Tag push; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          git update-ref "refs/heads/$BRANCH" HEAD
+          echo "::notice::Materialised refs/heads/$BRANCH at $(git rev-parse --short HEAD)"
 
       - name: Setup JDK
         uses: actions/setup-java@v5

.github/workflows/gradle-build.yml

@@ -37,6 +37,23 @@ jobs:
           # Needed for git-versioning to derive the branch-slug-SNAPSHOT version.
           fetch-depth: 0
 
+      - name: Create local branch ref for git-versioning
+        # See build-artifacts.yml — without this, git-versioning intermittently falls back
+        # to gradle.properties' static version and publishes under the wrong coordinate.
+        shell: bash
+        run: |
+          BRANCH="${GITHUB_HEAD_REF:-$GITHUB_REF_NAME}"
+          if [[ -z "$BRANCH" || "$BRANCH" == "HEAD" ]]; then
+            echo "::notice::No branch name; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          if [[ -z "$GITHUB_HEAD_REF" && "$GITHUB_REF" == refs/tags/* ]]; then
+            echo "::notice::Tag push; leaving git-versioning to its own detection."
+            exit 0
+          fi
+          git update-ref "refs/heads/$BRANCH" HEAD
+          echo "::notice::Materialised refs/heads/$BRANCH at $(git rev-parse --short HEAD)"
+
       - name: Setup Java
         uses: actions/setup-java@v5
         with: