SQLException during value generation causes (non transactional) connection leak

jdo/identity/pom.xml

@@ -26,6 +26,11 @@ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xs
             <artifactId>datanucleus-api-jdo</artifactId>
             <version>[${api.jdo.min.version}, ${api.jdo.max.version})</version>
         </dependency>
+        <dependency>
+            <groupId>com.github.zabetak</groupId>
+            <artifactId>jdbc-faulty</artifactId>
+            <version>2.0</version>
+        </dependency>
     </dependencies>
 
     <build>

jdo/identity/src/test/org/datanucleus/tests/ValueGeneratorRandomFailureTest.java

@@ -0,0 +1,101 @@
+/**********************************************************************
+Copyright (c) 2004 Andy Jefferson and others. All rights reserved. 
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+Contributors :
+ 2025 Stamatis Zampetakis - Test reproducing a connection leak when failures occur during value generation
+***********************************************************************/
+package org.datanucleus.tests;
+
+import com.github.zabetak.jdbc.faulty.ExceptionFault;
+import com.github.zabetak.jdbc.faulty.FaultyJDBCDriver;
+import org.datanucleus.samples.valuegeneration.TableGeneratorItem;
+
+import javax.jdo.PersistenceManager;
+import javax.jdo.Transaction;
+import java.util.Properties;
+
+/**
+ * Test value generators in the presence of random failures when calling {@link java.sql.Connection} methods.
+ */
+public class ValueGeneratorRandomFailureTest extends JDOPersistenceTestCase
+{
+    private static Properties userProperties() {
+        Properties factoryProperties = TestHelper.getFactoryProperties(1, null);
+        String url = factoryProperties.getProperty("datanucleus.ConnectionURL");
+        // Add the faulty proxy in front of the regular JDBC driver
+        String faultyURL = url.replace("jdbc", "jdbc:faulty");
+        Properties userProps = new Properties();
+        userProps.put("datanucleus.connectionURL", faultyURL);
+        return userProps;
+    }
+
+    public ValueGeneratorRandomFailureTest(String name) {
+        super(name, userProperties());
+    }
+
+    /**
+     *  In normal circumstances, the test should finish normally even though there are some occasional errors during
+     *  commit. Due to the connection leak, the test currently fails (most often with lock timeout exceptions).
+     */
+    public void testTableGeneratorWithFailureOnCommitFinishesWithoutErrors()
+    {
+        try {
+            for (int i = 0; i < 100; i++) {
+                PersistenceManager pm = pmf.getPersistenceManager();
+                Transaction tx = pm.currentTransaction();
+                try {
+                    tx.begin();
+                    // Generate a random exception on 10% of the calls to Connection#commit
+                    FaultyJDBCDriver.addFault("ex-fault-1", new ExceptionFault(0.1, "commit"));
+                    pm.makePersistent(new TableGeneratorItem("Item_" + i));
+                    FaultyJDBCDriver.clearFaults();
+                    tx.commit();
+                }
+                catch(Exception e)
+                {
+                    // If it is the artificially generated faulty exception ignore it and continue
+                    //  otherwise stop and propagate it
+                    if (!isFaultyException(e)) {
+                        throw e;
+                    }
+                }
+                finally
+                {
+                    if (tx.isActive()) {
+                        tx.rollback();
+                    }
+                    pm.close();
+                }
+            }
+        }
+        finally
+        {
+            // Remove all registered faults
+            FaultyJDBCDriver.clearFaults();
+            // Clean out any created data
+            clean(TableGeneratorItem.class);
+        }
+    }
+
+    private static boolean isFaultyException(Throwable e) {
+        if (e == null) {
+            return false;
+        }
+        if (e.getMessage() != null && "Random exception generated by jdbc-faulty".equals(e.getMessage())) {
+            return true;
+        }
+        return isFaultyException(e.getCause());
+    }
+
+}