HHH-19508 sort CollectionUpdateActions to move those with deletes to front of the line

Author: gavinking

hibernate-core/src/main/java/org/hibernate/action/internal/CollectionUpdateAction.java

@@ -7,6 +7,7 @@
 import org.hibernate.AssertionFailure;
 import org.hibernate.HibernateException;
 import org.hibernate.collection.spi.PersistentCollection;
+import org.hibernate.engine.spi.ComparableExecutable;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.event.monitor.spi.EventMonitor;
 import org.hibernate.event.spi.EventSource;
@@ -107,6 +108,23 @@ else if ( collection.needsRecreate( persister ) ) {
 		}
 	}
 
+	@Override
+	public int compareTo(ComparableExecutable o) {
+		if ( o instanceof CollectionUpdateAction that
+				&& getPrimarySortClassifier().equals( o.getPrimarySortClassifier() ) ) {
+			final CollectionPersister persister = getPersister();
+			boolean hasDeletes = this.getCollection().getDeletes( persister, false ).hasNext();
+			boolean otherHasDeletes = that.getCollection().getDeletes( persister, false ).hasNext();
+			if ( hasDeletes && !otherHasDeletes ) {
+				return -1;
+			}
+			if ( otherHasDeletes && !hasDeletes ) {
+				return 1;
+			}
+		}
+		return super.compareTo( o );
+	}
+
 	private void preUpdate() {
 		getEventListenerGroups().eventListenerGroup_PRE_COLLECTION_UPDATE
 				.fireLazyEventOnEachListener( this::newPreCollectionUpdateEvent,

hibernate-core/src/test/java/org/hibernate/orm/test/actionqueue/CollectionUpdateOrderingTest.java

@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.actionqueue;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+import org.hibernate.cfg.BatchSettings;
+import org.hibernate.testing.orm.junit.EntityManagerFactoryScope;
+import org.hibernate.testing.orm.junit.Jpa;
+import org.hibernate.testing.orm.junit.Setting;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+@Jpa(annotatedClasses =
+		{CollectionUpdateOrderingTest.Thing.class,
+		CollectionUpdateOrderingTest.OtherThing.class},
+		integrationSettings = @Setting(name = BatchSettings.ORDER_UPDATES, value = "true"))
+class CollectionUpdateOrderingTest {
+
+	@Test
+	void test(EntityManagerFactoryScope scope) {
+		scope.inTransaction( session -> {
+			Thing thing1 = new Thing();
+			Thing thing2 = new Thing();
+			thing2.id = 2;
+			thing1.id = 3; //bigger
+			OtherThing otherThing1 = new OtherThing();
+			OtherThing otherThing2 = new OtherThing();
+			otherThing1.id = 1;
+			otherThing2.id = 2;
+			thing1.otherThings.add(otherThing1);
+			thing1.otherThings.add(otherThing2);
+			session.persist( thing1 );
+			session.persist( thing2 );
+		} );
+		scope.inTransaction( session -> {
+			Thing thing2 = session.find(Thing.class, 2L);
+			Thing thing1 = session.find(Thing.class, 3L);
+			OtherThing otherThing = thing1.otherThings.iterator().next();
+			thing1.otherThings.remove(otherThing);
+			thing2.otherThings.add(otherThing);
+		});
+	}
+
+	@Entity
+	static class Thing {
+		@Id long id;
+		@OneToMany(cascade = CascadeType.PERSIST)
+		Set<OtherThing> otherThings = new HashSet<>();
+	}
+
+	@Entity
+	static class OtherThing {
+		@Id long id;
+	}
+}