Add support for checking out non-existent branches in JUnit reports workflow

Author: Donnerbart

.github/workflows/integration-test.yml

@@ -12,7 +12,7 @@ env:
   split-total: 4
 
 jobs:
-  checkout-junit-reports-test:
+  checkout-junit-reports:
     name: Checkout JUnit reports
     runs-on: ubuntu-latest
     steps:
@@ -162,11 +162,70 @@ jobs:
           name: junit-xml-reports-sha
           failOnError: false
 
+  checkout-junit-reports-with-nonexistent-branch:
+    name: Checkout JUnit reports with non-existent branch
+    runs-on: ubuntu-latest
+    needs:
+      - checkout-junit-reports
+    steps:
+      - name: Checkout split-tests-java-action
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
+
+      - name: Checkout JUnit reports (split-index 1)
+        uses: ./checkout-junit-reports
+        with:
+          split-index: 1
+          git-branch: junit-reports-it-nonexistent
+          path: junit-reports-first-index-1
+
+      - name: Checkout JUnit reports (split-index 0a)
+        uses: ./checkout-junit-reports
+        with:
+          split-index: 0
+          git-branch: junit-reports-it-nonexistent
+          path: junit-reports-first-index-0
+
+      - name: Checkout JUnit reports (split-index 2)
+        uses: ./checkout-junit-reports
+        with:
+          split-index: 2
+          git-branch: junit-reports-it-nonexistent
+          path: junit-reports-first-index-2
+
+      - name: Checkout JUnit reports (split-index 0b)
+        uses: ./checkout-junit-reports
+        with:
+          split-index: 0
+          git-branch: junit-reports-it-nonexistent
+          path: junit-reports-first-index-3
+
+      - name: Checkout JUnit reports (split-index 0c)
+        uses: ./checkout-junit-reports
+        with:
+          split-index: 0
+          git-branch: junit-reports-it-nonexistent
+          path: junit-reports-first-index-4
+          upload-artifact: false
+
+      - name: Assert JUnit reports
+        run: |
+          for SPLIT_INDEX in {0..3}; do
+            echo "Checking JUnit reports for split-index $SPLIT_INDEX"
+            cd junit-reports-first-index-$SPLIT_INDEX
+            FILE_COUNT=$(ls -1 | wc -l)
+            if [[ "$FILE_COUNT" -ne 0 ]]; then
+              echo "Error: Expected empty directory, but found $FILE_COUNT files!"
+              ls -l
+              exit 1
+            fi
+            cd ..
+          done
+
   generate-split-index-json:
     name: Generate split indexes
     runs-on: ubuntu-latest
     needs:
-      checkout-junit-reports-test
+      - checkout-junit-reports-with-nonexistent-branch
     outputs:
       json: ${{ steps.generate.outputs.split-index-json }}
     steps:

checkout-junit-reports/action.yml

@@ -49,40 +49,52 @@ runs:
         name: ${{ inputs.artifact-name }}
         path: ${{ inputs.artifact-path }}
 
+    - name: Checkout repository
+      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
+      with:
+        path: ${{ inputs.path }}
+
     - name: Check JUnit reports SHA
       id: junit-reports-sha
       shell: bash
+      working-directory: ${{ inputs.path }}
       run: |
         echo "Checking JUnit reports SHA"
         UPLOAD_SHA_ARTIFACT=${{ inputs.upload-artifact }}
         CHECKOUT_REF=${{ inputs.git-branch }}
-        if [ -d ${{ inputs.artifact-path }} ]; then
-          cd ${{ inputs.artifact-path }}
-          if [ -f junit-reports-sha.txt ]; then
+        if [ -f "../${{ inputs.artifact-path }}/junit-reports-sha.txt" ]; then
+          SAVED_SHA=$(cat "../${{ inputs.artifact-path }}/junit-reports-sha.txt")
+          echo "Checking out saved SHA '$SAVED_SHA' for repeatable test distribution"
+          git fetch --quiet
+          if git rev-parse --verify "$SAVED_SHA^{commit}" >/dev/null 2>&1; then
+            git checkout --quiet "$SAVED_SHA"
             UPLOAD_SHA_ARTIFACT=false
-            CHECKOUT_REF=$(cat junit-reports-sha.txt)
+          else
+            echo "Error: Saved SHA '$SAVED_SHA' is not a valid commit. Aborting checkout." >&2
+            exit 1
           fi
         else
-          mkdir ${{ inputs.artifact-path }} || true
-        fi
-        if [ "$UPLOAD_SHA_ARTIFACT" == "true" ]; then
-          echo "Checking out JUnit reports from branch $CHECKOUT_REF"
-        else
-          echo "Checking out JUnit reports from previously used SHA $CHECKOUT_REF"
+          # no SHA artifact exists, handle branch checkout and potentially create new SHA artifact
+          if git ls-remote --exit-code --heads origin "$CHECKOUT_REF"; then
+            echo "Switching to existing branch: $CHECKOUT_REF"
+            git fetch --quiet
+            git switch "$CHECKOUT_REF"
+          else
+            echo "Branch $CHECKOUT_REF does not exist, no JUnit test reports available"
+            rm -rf .
+            UPLOAD_SHA_ARTIFACT=false
+          fi
         fi
         # we can only upload the artifact once, so only do this on the first split
         if [ "${{ inputs.split-index }}" != "0" ]; then
           echo "Skipping upload of JUnit reports SHA on this index"
           UPLOAD_SHA_ARTIFACT=false
+        elif [ "$UPLOAD_SHA_ARTIFACT" == "true" ]; then
+          echo "Will upload JUnit reports SHA for branch $CHECKOUT_REF"
+        else
+          echo "Will not upload JUnit reports SHA"
         fi
         echo "upload-artifact=${UPLOAD_SHA_ARTIFACT}" >> "$GITHUB_OUTPUT"
-        echo "ref=${CHECKOUT_REF}" >> "$GITHUB_OUTPUT"
-
-    - name: Checkout repository
-      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
-      with:
-        path: ${{ inputs.path }}
-        ref: ${{ steps.junit-reports-sha.outputs.ref }}
 
     - name: Save JUnit reports SHA
       if: ${{ steps.junit-reports-sha.outputs.upload-artifact == 'true' }}
@@ -91,7 +103,8 @@ runs:
       run: |
         SHA=$(git rev-parse HEAD)
         echo "Saving JUnit reports SHA $SHA"
-        cd ../${{ inputs.artifact-path }}
+        mkdir -p "../${{ inputs.artifact-path }}"
+        cd "../${{ inputs.artifact-path }}"
         echo -n "$SHA" > junit-reports-sha.txt
 
     - name: Upload JUnit report SHA