Run mvn validate

.github/workflows/pull-request.yml

@@ -82,6 +82,34 @@ jobs:
       - uses: gradle/actions/setup-gradle@v4
       - run: ./gradlew checkstyleMain checkstyleTest pmdMain pmdTest
 
+  validate-pom:
+    name: Validate Publish POMs
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 21
+      - uses: gradle/actions/setup-gradle@v4
+      - name: Generate POMs
+        run: ./gradlew generatePomFileForMavenPublication
+      # Maven's built-in model validator catches the rule that bit us at v0.1.0:
+      # `'dependencies.dependency.version' for X is missing`. Resolves BOM imports
+      # (jackson-bom etc.), so deps managed via <dependencyManagement> are accepted.
+      # Does NOT check Central-specific completeness rules (name/description/license/scm) —
+      # the release gate (publishToMavenCentral against Central Portal) covers those.
+      - name: Validate POMs via Maven's model validator
+        run: |
+          set -e
+          failed=0
+          for pom in $(find . -path '*/build/publications/maven/pom-default.xml'); do
+            echo "::group::$pom"
+            mvn -B --no-transfer-progress -f "$pom" validate || failed=1
+            echo "::endgroup::"
+          done
+          exit $failed
+
   test-opa-evaluator:
     needs: check-changes
     if: needs.check-changes.outputs.opa-evaluator == 'true'
@@ -153,6 +181,7 @@ jobs:
     needs:
       - check-changes
       - lint
+      - validate-pom
       - test-opa-evaluator
       - test-opa-jackson
       - test-opa-services