HHH-14993 - EAGER non-inverse collection throws StackOverflowError if `max_fetch_depth` not set

hibernate-core/src/main/java/org/hibernate/loader/ast/internal/LoaderSelectBuilder.java

@@ -798,12 +798,8 @@ public class LoaderSelectBuilder {
 				joined = false;
 			}
 
-			boolean changeFetchDepth = !( fetchable instanceof BasicValuedModelPart )
-					&& !( fetchable instanceof EmbeddedAttributeMapping )
-					&& !( fetchable instanceof CollectionPart );
-
 			try {
-				if ( changeFetchDepth ) {
+				if ( fetchable.incrementFetchDepth() ) {
 					fetchDepth++;
 				}
 
@@ -877,7 +873,7 @@ public class LoaderSelectBuilder {
 				fetches.add( fetch );
 			}
 			finally {
-				if ( changeFetchDepth ) {
+				if ( fetchable.incrementFetchDepth() ) {
 					fetchDepth--;
 				}
 				// Only set the currentBagRole to the previous value for non-join fetches,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EntityCollectionPart.java

@@ -408,6 +408,12 @@ public class EntityCollectionPart
 		return this;
 	}
 
+	@Override
+	public boolean incrementFetchDepth() {
+		// the collection itself already increments the depth
+		return false;
+	}
+
 	@Override
 	public ModelPart findSubPart(String name) {
 		return findSubPart( name, null );

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/PluralAttributeMappingImpl.java

@@ -430,6 +430,27 @@ public class PluralAttributeMappingImpl
 		}
 	}
 
+	@Override
+	public Fetch resolveCircularFetch(
+			NavigablePath fetchablePath,
+			FetchParent fetchParent,
+			FetchTiming fetchTiming,
+			DomainResultCreationState creationState) {
+		if ( fetchTiming == FetchTiming.IMMEDIATE ) {
+			final boolean alreadyVisited = creationState.isAssociationKeyVisited( fkDescriptor.getAssociationKey() );
+			if ( alreadyVisited ) {
+				return createSelectEagerCollectionFetch(
+						fetchParent,
+						fetchablePath,
+						creationState,
+						creationState.getSqlAstCreationState()
+				);
+			}
+		}
+
+		return null;
+	}
+
 	private Fetch createSelectEagerCollectionFetch(
 			FetchParent fetchParent,
 			NavigablePath fetchablePath,

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/fetch/depth/NoDepthTests.java

@@ -0,0 +1,112 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.mapping.fetch.depth;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Map;
+import jakarta.persistence.EntityManagerFactory;
+
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.engine.spi.SessionFactoryImplementor;
+import org.hibernate.internal.util.collections.CollectionHelper;
+
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.junit.jupiter.api.Test;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.classloader.ShrinkWrapClassLoader;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+
+import static jakarta.persistence.Persistence.createEntityManagerFactory;
+import static org.hibernate.testing.transaction.TransactionUtil2.inTransaction;
+
+/**
+ * @author Steve Ebersole
+ */
+@JiraKey( "HHH-14993" )
+public class NoDepthTests {
+
+	@Test
+	public void testWithMax() {
+		testIt( true );
+	}
+
+	@Test
+	public void testNoMax() {
+		testIt( false );
+	}
+
+	private void testIt(boolean configureMaxDepth) {
+		try ( final SessionFactoryImplementor sf = buildSessionFactory( configureMaxDepth ) ) {
+			inTransaction( sf, (session) -> {
+				session.createSelectionQuery( "from SysModule" ).getResultList();
+				session.createSelectionQuery( "from SysModule2" ).getResultList();
+			} );
+		}
+	}
+
+	private static SessionFactoryImplementor buildSessionFactory(boolean configureMax) {
+		final StandardServiceRegistryBuilder registryBuilder = new StandardServiceRegistryBuilder();
+		registryBuilder.applySetting( AvailableSettings.URL, "jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1;" );
+		registryBuilder.applySetting( AvailableSettings.USER, "sa" );
+		registryBuilder.applySetting( AvailableSettings.POOL_SIZE, "5" );
+		registryBuilder.applySetting( AvailableSettings.FORMAT_SQL, "true" );
+		registryBuilder.applySetting( AvailableSettings.HBM2DDL_AUTO, "create-drop" );
+
+		if ( configureMax ) {
+			registryBuilder.applySetting( AvailableSettings.MAX_FETCH_DEPTH, "10" );
+		}
+		else {
+			registryBuilder.applySetting( AvailableSettings.MAX_FETCH_DEPTH, "" );
+		}
+
+		return new MetadataSources( registryBuilder.build() )
+				.addAnnotatedClasses( SysModule.class, SysModule2.class )
+				.buildMetadata()
+				.buildSessionFactory()
+				.unwrap( SessionFactoryImplementor.class );
+	}
+
+	@Test
+	public void testWithMaxJpa() {
+		testItJpa( "with-max" );
+	}
+
+	@Test
+	public void testNoMaxJpa() {
+		testItJpa( "no-max" );
+	}
+
+	private void testItJpa(String unitName) {
+		final JavaArchive par = ShrinkWrap.create( JavaArchive.class, unitName + ".par" );
+		par.addClasses( SysModule.class );
+		par.addAsResource( "units/many2many/fetch-depth.xml", "META-INF/persistence.xml" );
+
+		try ( final ShrinkWrapClassLoader classLoader = new ShrinkWrapClassLoader( par ) ) {
+			final Map<String, ?> settings = CollectionHelper.toMap(
+					AvailableSettings.CLASSLOADERS,
+					Arrays.asList( classLoader, getClass().getClassLoader() )
+			);
+
+			final EntityManagerFactory emf = createEntityManagerFactory( unitName, settings );
+			try ( final SessionFactoryImplementor sf = emf.unwrap( SessionFactoryImplementor.class ) ) {
+				// play around with the SF and make sure it is operable
+				inTransaction( sf, (s) -> {
+					s.createSelectionQuery( "from SysModule" ).list();
+					s.createSelectionQuery( "from SysModule2" ).list();
+				});
+			}
+		}
+		catch (IOException e) {
+			throw new RuntimeException( "re-throw", e );
+		}
+	}
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/fetch/depth/SysModule.java

@@ -0,0 +1,38 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.mapping.fetch.depth;
+
+import java.util.Set;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "sys_mod")
+public class SysModule {
+    @Id
+    private Integer id;
+
+    @Column(name = "name")
+    private String name;
+
+//    @OneToMany( cascade = CascadeType.PERSIST, fetch = FetchType.EAGER )
+//    @JoinColumn( name = "target_mod_fk" )
+    @ManyToMany( targetEntity = SysModule.class, cascade = { CascadeType.PERSIST }, fetch = FetchType.EAGER )
+    @JoinTable(
+            name = "sys_group_mod",
+            joinColumns = @JoinColumn(name = "src_fk", referencedColumnName = "id"),
+            inverseJoinColumns = @JoinColumn(name = "target_fk", referencedColumnName = "id")
+    )
+    private Set<SysModule> targetModules;
+}

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/fetch/depth/SysModule2.java

@@ -0,0 +1,31 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.mapping.fetch.depth;
+
+import java.util.Set;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "sys_mod")
+public class SysModule2 {
+    @Id
+    private Integer id;
+
+    @Column(name = "name")
+    private String name;
+
+    @OneToMany( cascade = CascadeType.PERSIST, fetch = FetchType.EAGER )
+    @JoinColumn( name = "target_mod_fk" )
+    private Set<SysModule2> targetModules;
+}

hibernate-core/src/test/resources/units/many2many/fetch-depth.xml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<persistence version="3.0" xmlns="https://jakarta.ee/xml/ns/persistence" 
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence https://jakarta.ee/xml/ns/persistence/persistence_3_0.xsd">
+
+    <persistence-unit name="no-max" transaction-type="RESOURCE_LOCAL" >
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+
+        <class>org.hibernate.orm.test.mapping.fetch.depth.SysModule</class>
+        <class>org.hibernate.orm.test.mapping.fetch.depth.SysModule2</class>
+
+        <properties>
+            <property name="hibernate.connection.url" value="jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1;"/>
+            <property name="hibernate.connection.username" value="sa"/>
+            <property name="hibernate.connection.pool_size" value="5"/>
+            <property name="hibernate.show_sql" value="true"/>
+            <property name="hibernate.format_sql" value="true"/>
+            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
+
+            <property name="hibernate.max_fetch_depth" value="" />
+        </properties>
+    </persistence-unit>
+
+    <persistence-unit name="with-max" transaction-type="RESOURCE_LOCAL" >
+        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+
+        <class>org.hibernate.orm.test.mapping.fetch.depth.SysModule</class>
+        <class>org.hibernate.orm.test.mapping.fetch.depth.SysModule2</class>
+
+        <properties>
+            <property name="hibernate.connection.url" value="jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1;"/>
+            <property name="hibernate.connection.username" value="sa"/>
+            <property name="hibernate.connection.pool_size" value="5"/>
+            <property name="hibernate.format_sql" value="true"/>
+            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
+
+            <property name="hibernate.max_fetch_depth" value="10" />
+        </properties>
+    </persistence-unit>
+
+</persistence>