Improve pre-bound JDBC Connection exception message

spring-orm/src/main/java/org/springframework/orm/jpa/JpaTransactionManager.java

@@ -389,9 +389,13 @@ protected void doBegin(Object transaction, TransactionDefinition definition) {
 		if (txObject.hasConnectionHolder() && !txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
 			throw new IllegalTransactionStateException(
 					"Pre-bound JDBC Connection found! JpaTransactionManager does not support " +
-					"running within DataSourceTransactionManager if told to manage the DataSource itself. " +
-					"It is recommended to use a single JpaTransactionManager for all transactions " +
-					"on a single DataSource, no matter whether JPA or JDBC access.");
+					"running within another transaction manager that exposes a JDBC Connection " +
+					"for the same DataSource (for example, a JpaTransactionManager or " +
+					"HibernateTransactionManager for a different persistence unit) if told to " +
+					"manage the DataSource itself. Alternatively, a JDBC Connection may have been " +
+					"left bound to the current thread. It is recommended to use a single " +
+					"JpaTransactionManager for all transactions on a single DataSource, " +
+					"no matter whether JPA or JDBC access.");
 		}
 
 		try {

spring-orm/src/main/java/org/springframework/orm/jpa/hibernate/HibernateTransactionManager.java

@@ -445,9 +445,13 @@ protected void doBegin(Object transaction, TransactionDefinition definition) {
 		if (txObject.hasConnectionHolder() && !txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
 			throw new IllegalTransactionStateException(
 					"Pre-bound JDBC Connection found! HibernateTransactionManager does not support " +
-					"running within DataSourceTransactionManager if told to manage the DataSource itself. " +
-					"It is recommended to use a single HibernateTransactionManager for all transactions " +
-					"on a single DataSource, no matter whether Hibernate or JDBC access.");
+					"running within another transaction manager that exposes a JDBC Connection " +
+					"for the same DataSource (for example, a HibernateTransactionManager or " +
+					"JpaTransactionManager for a different SessionFactory) if told to manage " +
+					"the DataSource itself. Alternatively, a JDBC Connection may have been " +
+					"left bound to the current thread. It is recommended to use a single " +
+					"HibernateTransactionManager for all transactions on a single DataSource, " +
+					"no matter whether Hibernate or JDBC access.");
 		}
 
 		SessionImplementor session = null;

spring-orm/src/test/java/org/springframework/orm/jpa/JpaTransactionManagerTests.java

@@ -16,8 +16,11 @@
 
 package org.springframework.orm.jpa;
 
+import java.sql.Connection;
 import java.util.List;
 
+import javax.sql.DataSource;
+
 import jakarta.persistence.EntityManager;
 import jakarta.persistence.EntityManagerFactory;
 import jakarta.persistence.EntityTransaction;
@@ -26,6 +29,9 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.jdbc.datasource.ConnectionHandle;
+import org.springframework.jdbc.datasource.SimpleConnectionHandle;
+import org.springframework.transaction.IllegalTransactionStateException;
 import org.springframework.transaction.InvalidIsolationLevelException;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionSystemException;
@@ -613,4 +619,37 @@ void transactionFlush() {
 		verify(manager).close();
 	}
 
+	@Test  // gh-14130
+	void transactionWithinOtherTransactionManagerForSameDataSource() {
+		DataSource dataSource = mock();
+		Connection connection = mock();
+		JpaDialect jpaDialect = new DefaultJpaDialect() {
+			@Override
+			public ConnectionHandle getJdbcConnection(EntityManager entityManager, boolean readOnly) {
+				return new SimpleConnectionHandle(connection);
+			}
+		};
+
+		EntityManagerFactory otherFactory = mock();
+		EntityManager otherManager = mock();
+		given(otherFactory.createEntityManager()).willReturn(otherManager);
+		given(otherManager.getTransaction()).willReturn(mock());
+		given(otherManager.isOpen()).willReturn(true);
+
+		JpaTransactionManager otherTm = new JpaTransactionManager(otherFactory);
+		otherTm.setDataSource(dataSource);
+		otherTm.setJpaDialect(jpaDialect);
+		tm.setDataSource(dataSource);
+		tm.setJpaDialect(jpaDialect);
+
+		assertThatExceptionOfType(IllegalTransactionStateException.class)
+				.isThrownBy(() -> new TransactionTemplate(otherTm).executeWithoutResult(status ->
+						tt.executeWithoutResult(innerStatus -> {})))
+				.withMessageStartingWith("Pre-bound JDBC Connection found!")
+				.withMessageContaining("another transaction manager")
+				.withMessageNotContaining("DataSourceTransactionManager");
+
+		verify(otherManager).close();
+	}
+
 }