(Try to) add a reproducer for #10869

lib/Doctrine/ORM/UnitOfWork.php

@@ -1167,7 +1167,26 @@ private function executeInserts(): void
         $entities = $this->computeInsertExecutionOrder();
 
         foreach ($entities as $entity) {
-            $oid       = spl_object_id($entity);
+            $oid = spl_object_id($entity);
+
+            // Mitigation for GH-10869:
+            // Users may use postPersist and similar listeners to make entity updates and call
+            // EM::flush() -> UoW::commit() again, while a transaction is currently running.
+            // This "somehow" worked pre 2.16, although it was never officially endorsed and/or
+            // is disputed (and there is no guarantee that the UoW will be able to deal with this,
+            // does not lose updates etc.).
+            // https://github.com/doctrine/orm/pull/10900 is a discussion about deprecating this
+            // kind of reentrance and disallowing it in 3.0.
+            //
+            // However, to ease the pain somewhat for users in 2.16, this condition covers that
+            // a reentrant call into UoW::commit() may have processed pending insertions that we
+            // had in our computed insertion order. So, after the second (inner) commit() returned
+            // and the outer one continues, deal with the situation that entities are no longer in
+            // the set of pending insertions.
+            if (! isset($this->entityInsertions[$oid])) {
+                continue;
+            }
+
             $class     = $this->em->getClassMetadata(get_class($entity));
             $persister = $this->getEntityPersister($class->name);
             $invoke    = $this->listenersInvoker->getSubscribedSystems($class, Events::postPersist);

tests/Doctrine/Tests/ORM/Functional/Ticket/GH10869Test.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\ORM\Event\PostPersistEventArgs;
+use Doctrine\ORM\Events;
+use Doctrine\ORM\Mapping as ORM;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+use function sprintf;
+
+class GH10869Test extends OrmFunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->setUpEntitySchema([
+            GH10869Entity::class,
+        ]);
+    }
+
+    public function testPostPersistListenerUpdatingObjectFieldWhileOtherInsertPending(): void
+    {
+        $entity1 = new GH10869Entity();
+        $this->_em->persist($entity1);
+
+        $entity2 = new GH10869Entity();
+        $this->_em->persist($entity2);
+
+        $this->_em->getEventManager()->addEventListener(Events::postPersist, new class {
+            public function postPersist(PostPersistEventArgs $args): void
+            {
+                $object = $args->getObject();
+
+                $objectManager = $args->getObjectManager();
+                $object->field = sprintf('test %s', $object->id);
+                $objectManager->flush();
+            }
+        });
+
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $entity1Reloaded = $this->_em->find(GH10869Entity::class, $entity1->id);
+        self::assertSame($entity1->field, $entity1Reloaded->field);
+
+        $entity2Reloaded = $this->_em->find(GH10869Entity::class, $entity2->id);
+        self::assertSame($entity2->field, $entity2Reloaded->field);
+    }
+}
+
+/**
+ * @ORM\Entity
+ */
+class GH10869Entity
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue
+     * @ORM\Column(type="integer")
+     *
+     * @var ?int
+     */
+    public $id;
+
+    /**
+     * @ORM\Column(type="text", nullable=true)
+     *
+     * @var ?string
+     */
+    public $field;
+}