Allow skipping of persistence.xml parsing

Fixes quarkusio#6805

extensions/hibernate-orm/deployment/src/main/java/io/quarkus/hibernate/orm/deployment/HibernateOrmProcessor.java

@@ -128,7 +128,7 @@
  * @author Sanne Grinovero <[email protected]>
  */
 public final class HibernateOrmProcessor {
-
+    public static final String SKIP_PARSE_PERSISTENCE_XML = "SKIP_PARSE_PERSISTENCE_XML";
     public static final String HIBERNATE_ORM_CONFIG_PREFIX = "quarkus.hibernate-orm.";
     public static final String NO_SQL_LOAD_SCRIPT_FILE = "no-file";
 
@@ -176,9 +176,11 @@ List<HotDeploymentWatchedFileBuildItem> hotDeploymentWatchedFiles(LaunchModeBuil
     @BuildStep
     public void parsePersistenceXmlDescriptors(
             BuildProducer<PersistenceXmlDescriptorBuildItem> persistenceXmlDescriptorBuildItemBuildProducer) {
-        List<ParsedPersistenceXmlDescriptor> explicitDescriptors = QuarkusPersistenceXmlParser.locatePersistenceUnits();
-        for (ParsedPersistenceXmlDescriptor desc : explicitDescriptors) {
-            persistenceXmlDescriptorBuildItemBuildProducer.produce(new PersistenceXmlDescriptorBuildItem(desc));
+        if (!"true".equals(System.getProperty(SKIP_PARSE_PERSISTENCE_XML, "false"))) {
+            List<ParsedPersistenceXmlDescriptor> explicitDescriptors = QuarkusPersistenceXmlParser.locatePersistenceUnits();
+            for (ParsedPersistenceXmlDescriptor desc : explicitDescriptors) {
+                persistenceXmlDescriptorBuildItemBuildProducer.produce(new PersistenceXmlDescriptorBuildItem(desc));
+            }
         }
     }
 

extensions/hibernate-orm/deployment/src/test/java/io/quarkus/hibernate/orm/ExcludePersistenceXmlConfigTest.java

@@ -0,0 +1,51 @@
+package io.quarkus.hibernate.orm;
+
+import javax.enterprise.inject.Instance;
+import javax.inject.Inject;
+import javax.persistence.EntityManager;
+
+import io.quarkus.hibernate.orm.deployment.HibernateOrmProcessor;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.arc.Arc;
+import io.quarkus.hibernate.orm.enhancer.Address;
+import io.quarkus.test.QuarkusUnitTest;
+
+public class ExcludePersistenceXmlConfigTest {
+
+    @RegisterExtension
+    static QuarkusUnitTest runner = new QuarkusUnitTest().
+            setBeforeAllCustomizer(() -> System.setProperty(HibernateOrmProcessor.SKIP_PARSE_PERSISTENCE_XML, "true")).
+            setAfterAllCustomizer(() -> System.getProperties().remove(HibernateOrmProcessor.SKIP_PARSE_PERSISTENCE_XML)).
+            setArchiveProducer(() -> ShrinkWrap.create(JavaArchive.class)
+                    .addClass(Address.class)
+                    .addAsManifestResource("META-INF/some-persistence.xml", "persistence.xml")
+                    .addAsResource("application.properties"));
+
+    @Inject
+    EntityManager entityManager;
+
+    @Inject
+    Instance<EntityManager> entityManagers;
+
+    @Test
+    public void testPersistenceAndConfigTest() {
+        // We have an entity manager
+        Assertions.assertNotNull(entityManager);
+        // We have exactly one entity manager
+        Assertions.assertEquals(false, entityManagers.isAmbiguous());
+        Arc.container().requestContext().activate();
+        try {
+            // it is the default entity manager from application.properties, not templatePU from the persistence.xml
+            Assertions.assertEquals("default",
+                    entityManager.getEntityManagerFactory().getProperties().get("hibernate.ejb.persistenceUnitName"));
+        } finally {
+            Arc.container().requestContext().deactivate();
+        }
+    }
+
+}