Add test to show why delete-before-insert may be challenging

tests/Doctrine/Tests/ORM/Functional/Ticket/GH5742Test.php

@@ -0,0 +1,158 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\Collections\Collection;
+use Doctrine\ORM\Mapping as ORM;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+class GH5742Test extends OrmFunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->createSchemaForModels(
+            GH5742Person::class,
+            GH5742Toothbrush::class,
+            GH5742ToothpasteBrand::class
+        );
+    }
+
+    public function testUpdateOneToOneToNewEntityBeforePreviousEntityCanBeRemoved(): void
+    {
+        $person             = new GH5742Person();
+        $oldToothbrush      = new GH5742Toothbrush();
+        $person->toothbrush = $oldToothbrush;
+
+        $this->_em->persist($person);
+        $this->_em->persist($oldToothbrush);
+        $this->_em->flush();
+
+        $oldToothbrushId = $oldToothbrush->id;
+
+        $newToothbrush      = new GH5742Toothbrush();
+        $person->toothbrush = $newToothbrush;
+
+        $this->_em->remove($oldToothbrush);
+        $this->_em->persist($newToothbrush);
+
+        // The flush operation will have to make sure the new toothbrush
+        // has been written to the database
+        // _before_ the person can be updated to refer to it.
+        // Likewise, the update must have happened _before_ the old
+        // toothbrush can be removed (non-nullable FK constraint).
+
+        $this->_em->flush();
+
+        $this->_em->clear();
+        self::assertSame($newToothbrush->id, $this->_em->find(GH5742Person::class, $person->id)->toothbrush->id);
+        self::assertNull($this->_em->find(GH5742Toothbrush::class, $oldToothbrushId));
+    }
+
+    public function testManyToManyCollectionUpdateBeforeRemoval(): void
+    {
+        $person             = new GH5742Person();
+        $person->toothbrush = new GH5742Toothbrush(); // to satisfy not-null constraint
+        $this->_em->persist($person);
+
+        $oldMice = new GH5742ToothpasteBrand();
+        $this->_em->persist($oldMice);
+
+        $person->preferredBrands->set(1, $oldMice);
+        $this->_em->flush();
+
+        $oldBrandId = $oldMice->id;
+
+        $newSpice = new GH5742ToothpasteBrand();
+        $this->_em->persist($newSpice);
+
+        $person->preferredBrands->set(1, $newSpice);
+
+        $this->_em->remove($oldMice);
+
+        // The flush operation will have to make sure the new brand
+        // has been written to the database _before_ it can be referred
+        // to from the m2m join table.
+        // Likewise, the old join table entry must have been removed
+        // _before_ the old brand can be removed.
+
+        $this->_em->flush();
+
+        $this->_em->clear();
+        self::assertCount(1, $this->_em->find(GH5742Person::class, $person->id)->preferredBrands);
+        self::assertNull($this->_em->find(GH5742ToothpasteBrand::class, $oldBrandId));
+    }
+}
+
+/**
+ * @ORM\Entity
+ */
+class GH5742Person
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue(strategy="AUTO")
+     * @ORM\Column(type="integer")
+     *
+     * @var int
+     */
+    public $id;
+
+    /**
+     * @ORM\OneToOne(targetEntity="GH5742Toothbrush", cascade={"persist"})
+     * @ORM\JoinColumn(nullable=false)
+     *
+     * @var GH5742Toothbrush
+     */
+    public $toothbrush;
+
+    /**
+     * @ORM\ManyToMany(targetEntity="GH5742ToothpasteBrand")
+     * @ORM\JoinTable(name="gh5742person_gh5742toothpastebrand",
+     *      joinColumns={@ORM\JoinColumn(name="person_id", referencedColumnName="id", onDelete="CASCADE")},
+     *      inverseJoinColumns={@ORM\JoinColumn(name="brand_id", referencedColumnName="id")}
+     * )
+     *
+     * @var Collection<GH5742ToothpasteBrand>
+     */
+    public $preferredBrands;
+
+    public function __construct()
+    {
+        $this->preferredBrands = new ArrayCollection();
+    }
+}
+
+/**
+ * @ORM\Entity
+ */
+class GH5742Toothbrush
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue(strategy="AUTO")
+     * @ORM\Column(type="integer")
+     *
+     * @var int
+     */
+    public $id;
+}
+
+/**
+ * @ORM\Entity
+ */
+class GH5742ToothpasteBrand
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue(strategy="AUTO")
+     * @ORM\Column(type="integer")
+     *
+     * @var int
+     */
+    public $id;
+}