Add CI coverage summaries and aggregate JaCoCo report (#6451)

.github/workflows/backend-build.yml

@@ -1,8 +1,14 @@
 name: Backend build, format check, and coverage
 
 # Reusable workflow called from build.yml. Runs the backend build matrix
-# (JDK 25 × spring-security on/off), Spotless formatting check, JUnit, and
+# (JDK 25 × every flavor), Spotless formatting check, JUnit, and
 # posts Jacoco coverage to PRs.
+#
+# Flavor axis (maps to STIRLING_FLAVOR in settings.gradle):
+#   core         - DISABLE_ADDITIONAL_FEATURES=true, no proprietary, no saas
+#   proprietary  - default build, no saas
+#   saas         - proprietary + the saas subproject (build + JUnit only,
+#                  never any runtime/integration testing)
 on:
   workflow_call:
 
@@ -25,7 +31,7 @@ jobs:
       fail-fast: false
       matrix:
         jdk-version: [25]
-        spring-security: [true, false]
+        flavor: [core, proprietary, saas]
     steps:
       - name: Harden Runner
         uses: step-security/harden-runner@ab7a9404c0f3da075243ca237b5fac12c98deaa5 # v2.19.3
@@ -58,7 +64,10 @@ jobs:
       - name: Install Task
         uses: go-task/setup-task@3be4020d41929789a01026e0e427a4321ce0ad44 # v2.0.0
       - name: Check Java formatting (Spotless)
-        if: matrix.jdk-version == 25 && matrix.spring-security == false
+        # Runs once per matrix combination - pick the cheapest leg
+        # (core - no proprietary, no saas) so we don't wait for the
+        # heavier flavors just to fail formatting.
+        if: matrix.jdk-version == 25 && matrix.flavor == 'core'
         id: spotless-check
         run: task backend:format:check
         continue-on-error: true
@@ -143,17 +152,24 @@ jobs:
               });
             }
 
-      - name: Build with Gradle and spring security ${{ matrix.spring-security }}
+      - name: Build with Gradle (flavor=${{ matrix.flavor }})
+        # STIRLING_FLAVOR is read by settings.gradle and expands into the
+        # right combination of DISABLE_ADDITIONAL_FEATURES + ENABLE_SAAS
+        # so we don't have to set them by hand. The saas flavor pulls in
+        # the app/saas subproject (unit tests only - no runtime tests).
         run: task backend:build:ci
         env:
           MAVEN_USER: ${{ secrets.MAVEN_USER }}
           MAVEN_PASSWORD: ${{ secrets.MAVEN_PASSWORD }}
           MAVEN_PUBLIC_URL: ${{ secrets.MAVEN_PUBLIC_URL }}
-          DISABLE_ADDITIONAL_FEATURES: ${{ matrix.spring-security }}
+          STIRLING_FLAVOR: ${{ matrix.flavor }}
 
       - name: Check Test Reports Exist
         if: always()
         run: |
+          # Common + core + proprietary always build (proprietary is
+          # excluded only at runtime, not from the gradle subproject
+          # graph). Saas builds add a fourth report dir.
           declare -a dirs=(
             "app/core/build/reports/tests/"
             "app/core/build/test-results/"
@@ -162,6 +178,9 @@ jobs:
             "app/proprietary/build/reports/tests/"
             "app/proprietary/build/test-results/"
           )
+          if [ "${{ matrix.flavor }}" = "saas" ]; then
+            dirs+=("app/saas/build/reports/tests/" "app/saas/build/test-results/")
+          fi
           for dir in "${dirs[@]}"; do
             if [ ! -d "$dir" ]; then
               echo "Missing $dir"
@@ -173,7 +192,7 @@ jobs:
         if: always()
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
-          name: test-reports-jdk-${{ matrix.jdk-version }}-spring-security-${{ matrix.spring-security }}
+          name: test-reports-jdk-${{ matrix.jdk-version }}-flavor-${{ matrix.flavor }}
           path: |
             app/**/build/reports/jacoco/test
             app/**/build/reports/tests/
@@ -183,7 +202,47 @@ jobs:
           retention-days: 3
           if-no-files-found: warn
 
-      - name: Add coverage to PR with spring security ${{ matrix.spring-security }} and JDK ${{ matrix.jdk-version }}
+      - name: Install defusedxml for coverage summary
+        # coverage-summary.py parses JaCoCo XML through defusedxml to
+        # silence security scanners that pattern-match on the stdlib
+        # xml.etree.ElementTree.parse call.
+        if: always() && matrix.flavor == 'saas'
+        run: python -m pip install --quiet defusedxml
+
+      - name: JaCoCo coverage step summary
+        # Only the saas leg posts the JUnit summary - it's a strict
+        # superset of the core + proprietary legs (same .exec files plus
+        # the saas subproject). Posting from all three would mean three
+        # near-identical tables crowding out the aggregate report.
+        if: always() && matrix.flavor == 'saas'
+        run: |
+          python scripts/coverage-summary.py \
+            --title "Backend JUnit coverage (JDK ${{ matrix.jdk-version }})" \
+            --jacoco "common=app/common/build/reports/jacoco/test/jacocoTestReport.xml" \
+            --jacoco "core=app/core/build/reports/jacoco/test/jacocoTestReport.xml" \
+            --jacoco "proprietary=app/proprietary/build/reports/jacoco/test/jacocoTestReport.xml" \
+            --jacoco "saas=app/saas/build/reports/jacoco/test/jacocoTestReport.xml" \
+            --github-step-summary
+
+      - name: Upload raw JUnit .exec for aggregate merge
+        # Same dedup rationale as the summary step: upload from the saas
+        # leg only (the most complete set, includes app/saas/.../test.exec)
+        # so the aggregate workflow merges the union rather than three
+        # overlapping subsets.
+        #
+        # Separate artifact from the HTML reports so the aggregate
+        # workflow can grab just the .exec files with a name pattern
+        # (`jacoco-exec-*`) instead of unpacking the whole test-reports
+        # tarball.
+        if: always() && matrix.flavor == 'saas'
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: jacoco-exec-junit-jdk-${{ matrix.jdk-version }}
+          path: app/*/build/jacoco/*.exec
+          retention-days: 7
+          if-no-files-found: warn
+
+      - name: Add coverage to PR (flavor=${{ matrix.flavor }}, JDK=${{ matrix.jdk-version }})
         # The action only supports the pull_request event (it posts a PR comment),
         # so skip it for merge_group runs and workflow_dispatch.
         if: github.event_name == 'pull_request'