fix(has-many): keep children when a nullable collection is reordered

src/Relation/HasMany.php

@@ -242,13 +242,18 @@ protected function getReferenceScope(Node $node): ?array
      */
     protected function calcDeleted(iterable $related, iterable $original): array
     {
-        $related = $this->extract($related);
-        $original = $this->extract($original);
-        return \array_udiff(
-            $original ?? [],
-            $related,
-            // static fn(object $a, object $b): int => strcmp(spl_object_hash($a), spl_object_hash($b))
-            static fn(object $a, object $b): int => (int) ($a === $b) - 1,
-        );
+        $relatedIds = [];
+        foreach ($this->extract($related) as $item) {
+            $relatedIds[\spl_object_id($item)] = true;
+        }
+
+        $deleted = [];
+        foreach ($this->extract($original) as $item) {
+            if (!isset($relatedIds[\spl_object_id($item)])) {
+                $deleted[] = $item;
+            }
+        }
+
+        return $deleted;
     }
 }

tests/ORM/Functional/Driver/Common/Integration/Case575/CaseTest.php

@@ -0,0 +1,137 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575;
+
+use Cycle\ORM\Heap\Heap;
+use Cycle\ORM\Select;
+use Cycle\ORM\Tests\Functional\Driver\Common\BaseTest;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\IntegrationTestTrait;
+use Cycle\ORM\Tests\Traits\TableTrait;
+
+/**
+ * Changing the order of a nullable HasMany collection must not detach the children that stay in it.
+ */
+abstract class CaseTest extends BaseTest
+{
+    use IntegrationTestTrait;
+    use TableTrait;
+
+    public function testReorderKeepsChildren(): void
+    {
+        $user = $this->fetchUser();
+        $user->comments = \array_reverse($user->comments);
+
+        $this->captureWriteQueries();
+        $this->save($user);
+        $this->assertOwnedComments(['comment 1', 'comment 2', 'comment 3']);
+        $this->assertNumWrites(0);
+    }
+
+    public function testPrependKeepsChildren(): void
+    {
+        $user = $this->fetchUser();
+        $comment = new Entity\Comment('comment 4');
+        $comment->user = $user;
+        \array_unshift($user->comments, $comment);
+
+        $this->captureWriteQueries();
+        $this->save($user);
+        $this->assertOwnedComments(['comment 1', 'comment 2', 'comment 3', 'comment 4']);
+        $this->assertNumWrites(1);
+    }
+
+    public function testReplaceInTheMiddleDetachesOnlyReplacedChild(): void
+    {
+        $user = $this->fetchUser();
+        $user->comments[1]->user = null;
+        $comment = new Entity\Comment('comment 4');
+        $comment->user = $user;
+        $user->comments[1] = $comment;
+
+        $this->captureWriteQueries();
+        $this->save($user);
+        $this->assertOwnedComments(['comment 1', 'comment 3', 'comment 4']);
+        $this->assertNumWrites(2);
+        $this->assertSame(
+            ['comment 2'],
+            $this->getDatabase()->table('comment')
+                ->select('content')
+                ->where('user_id', null)
+                ->fetchAll(\PDO::FETCH_COLUMN),
+        );
+    }
+
+    public function setUp(): void
+    {
+        // Init DB
+        parent::setUp();
+        $this->makeTables();
+        $this->fillData();
+
+        $this->loadSchema(__DIR__ . '/schema.php');
+    }
+
+    private function fetchUser(): Entity\User
+    {
+        $user = (new Select($this->orm, Entity\User::class))
+            ->load('comments')
+            ->wherePK(1)
+            ->fetchOne();
+
+        $this->assertInstanceOf(Entity\User::class, $user);
+        $this->assertCount(3, $user->comments);
+
+        return $user;
+    }
+
+    /**
+     * @param list<non-empty-string> $expected Contents of the user's comments, in id order.
+     */
+    private function assertOwnedComments(array $expected): void
+    {
+        $user = (new Select($this->orm->withHeap(new Heap()), Entity\User::class))
+            ->load('comments')
+            ->wherePK(1)
+            ->fetchOne();
+
+        $this->assertSame(
+            $expected,
+            \array_map(static fn(Entity\Comment $comment): string => $comment->content, $user->comments),
+        );
+    }
+
+    private function makeTables(): void
+    {
+        $this->makeTable(Entity\User::ROLE, [
+            'id' => 'primary',
+            'login' => 'string',
+        ]);
+
+        $this->makeTable(Entity\Comment::ROLE, [
+            'id' => 'primary',
+            'content' => 'string',
+            'user_id' => 'int,nullable',
+        ]);
+        $this->makeFK(Entity\Comment::ROLE, 'user_id', Entity\User::ROLE, 'id', 'NO ACTION', 'NO ACTION');
+    }
+
+    private function fillData(): void
+    {
+        $this->getDatabase()->table('user')->insertMultiple(
+            ['login'],
+            [
+                ['user-1'],
+            ],
+        );
+        $this->getDatabase()->table('comment')->insertMultiple(
+            ['user_id', 'content'],
+            [
+                [1, 'comment 1'],
+                [1, 'comment 2'],
+                [1, 'comment 3'],
+            ],
+        );
+    }
+}

tests/ORM/Functional/Driver/Common/Integration/Case575/Entity/Comment.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\Entity;
+
+class Comment
+{
+    public const ROLE = 'comment';
+
+    public ?int $id = null;
+    public string $content;
+    public ?User $user = null;
+    public ?int $user_id = null;
+
+    public function __construct(string $content)
+    {
+        $this->content = $content;
+    }
+}

tests/ORM/Functional/Driver/Common/Integration/Case575/Entity/User.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\Entity;
+
+class User
+{
+    public const ROLE = 'user';
+
+    public ?int $id = null;
+    public string $login;
+
+    /** @var list<Comment> */
+    public array $comments = [];
+
+    public function __construct(string $login)
+    {
+        $this->login = $login;
+    }
+}

tests/ORM/Functional/Driver/Common/Integration/Case575/schema.php

@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+use Cycle\ORM\Mapper\Mapper;
+use Cycle\ORM\Relation;
+use Cycle\ORM\SchemaInterface as Schema;
+use Cycle\ORM\Select\Repository;
+use Cycle\ORM\Select\Source;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\Entity\Comment;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\Entity\User;
+
+return [
+    User::ROLE => [
+        Schema::ENTITY => User::class,
+        Schema::MAPPER => Mapper::class,
+        Schema::SOURCE => Source::class,
+        Schema::REPOSITORY => Repository::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'user',
+        Schema::PRIMARY_KEY => ['id'],
+        Schema::FIND_BY_KEYS => ['id'],
+        Schema::COLUMNS => [
+            'id' => 'id',
+            'login' => 'login',
+        ],
+        Schema::RELATIONS => [
+            'comments' => [
+                Relation::TYPE => Relation::HAS_MANY,
+                Relation::TARGET => Comment::ROLE,
+                Relation::COLLECTION_TYPE => 'array',
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => true,
+                    Relation::WHERE => [],
+                    Relation::ORDER_BY => ['id' => 'ASC'],
+                    Relation::INNER_KEY => ['id'],
+                    Relation::OUTER_KEY => 'user_id',
+                ],
+            ],
+        ],
+        Schema::TYPECAST => [
+            'id' => 'int',
+        ],
+        Schema::SCHEMA => [],
+    ],
+    Comment::ROLE => [
+        Schema::ENTITY => Comment::class,
+        Schema::MAPPER => Mapper::class,
+        Schema::SOURCE => Source::class,
+        Schema::REPOSITORY => Repository::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'comment',
+        Schema::PRIMARY_KEY => ['id'],
+        Schema::FIND_BY_KEYS => ['id'],
+        Schema::COLUMNS => [
+            'id' => 'id',
+            'content' => 'content',
+            'user_id' => 'user_id',
+        ],
+        Schema::RELATIONS => [
+            'user' => [
+                Relation::TYPE => Relation::BELONGS_TO,
+                Relation::TARGET => User::ROLE,
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => true,
+                    Relation::INNER_KEY => 'user_id',
+                    Relation::OUTER_KEY => ['id'],
+                ],
+            ],
+        ],
+        Schema::TYPECAST => [
+            'id' => 'int',
+            'user_id' => 'int',
+        ],
+        Schema::SCHEMA => [],
+    ],
+];

tests/ORM/Functional/Driver/MySQL/Integration/Case575/CaseTest.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\MySQL\Integration\Case575;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-mysql
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'mysql';
+}

tests/ORM/Functional/Driver/Postgres/Integration/Case575/CaseTest.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Postgres\Integration\Case575;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-postgres
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'postgres';
+}

tests/ORM/Functional/Driver/SQLServer/Integration/Case575/CaseTest.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\SQLServer\Integration\Case575;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-sqlserver
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'sqlserver';
+}

tests/ORM/Functional/Driver/SQLite/Integration/Case575/CaseTest.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\SQLite\Integration\Case575;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case575\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-sqlite
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'sqlite';
+}