Add rule to prevent final constructors in Doctrine entities

rules.neon

@@ -27,6 +27,8 @@ rules:
 conditionalTags:
 	PHPStan\Rules\Doctrine\ORM\EntityMappingExceptionRule:
 		phpstan.rules.rule: %featureToggles.bleedingEdge%
+	PHPStan\Rules\Doctrine\ORM\EntityConstructorNotFinalRule:
+		phpstan.rules.rule: %featureToggles.bleedingEdge%
 
 services:
 	-
@@ -54,3 +56,5 @@ services:
 			bleedingEdge: %featureToggles.bleedingEdge%
 		tags:
 			- phpstan.rules.rule
+	-
+		class: PHPStan\Rules\Doctrine\ORM\EntityConstructorNotFinalRule

src/Rules/Doctrine/ORM/EntityConstructorNotFinalRule.php

@@ -0,0 +1,63 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Doctrine\ORM;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\ClassMethod;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\ShouldNotHappenException;
+use PHPStan\Type\Doctrine\ObjectMetadataResolver;
+use function sprintf;
+
+/**
+ * @implements Rule<ClassMethod>
+ */
+class EntityConstructorNotFinalRule implements Rule
+{
+
+	/** @var ObjectMetadataResolver */
+	private $objectMetadataResolver;
+
+	public function __construct(ObjectMetadataResolver $objectMetadataResolver)
+	{
+		$this->objectMetadataResolver = $objectMetadataResolver;
+	}
+
+	public function getNodeType(): string
+	{
+		return ClassMethod::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		if ($node->name->name !== '__construct') {
+			return [];
+		}
+
+		if (!$node->isFinal()) {
+			return [];
+		}
+
+		$classReflection = $scope->getClassReflection();
+		if ($classReflection === null) {
+			throw new ShouldNotHappenException();
+		}
+
+		if ($this->objectMetadataResolver->isTransient($classReflection->getName())) {
+			return [];
+		}
+
+		$metadata = $this->objectMetadataResolver->getClassMetadata($classReflection->getName());
+		if ($metadata !== null && $metadata->isEmbeddedClass === true) {
+			return [];
+		}
+
+		return [RuleErrorBuilder::message(sprintf(
+			'Constructor of class %s is final which can cause problems with proxies.',
+			$classReflection->getDisplayName()
+		))->build()];
+	}
+
+}

tests/Rules/Doctrine/ORM/EntityConstructorNotFinalRuleTest.php

@@ -0,0 +1,87 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Doctrine\ORM;
+
+use Iterator;
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use PHPStan\Type\Doctrine\ObjectMetadataResolver;
+
+/**
+ * @extends RuleTestCase<EntityConstructorNotFinalRule>
+ */
+class EntityConstructorNotFinalRuleTest extends RuleTestCase
+{
+
+	/** @var string|null */
+	private $objectManagerLoader;
+
+	protected function getRule(): Rule
+	{
+		return new EntityConstructorNotFinalRule(
+			new ObjectMetadataResolver($this->objectManagerLoader)
+		);
+	}
+
+	/**
+	 * @dataProvider ruleProvider
+	 * @param list<array{0: string, 1: int, 2?: string}> $expectedErrors
+	 */
+	public function testRule(string $file, array $expectedErrors): void
+	{
+		$this->objectManagerLoader = __DIR__ . '/entity-manager.php';
+		$this->analyse([$file], $expectedErrors);
+	}
+
+	/**
+	 * @dataProvider ruleProvider
+	 * @param list<array{0: string, 1: int, 2?: string}> $expectedErrors
+	 */
+	public function testRuleWithoutObjectManagerLoader(string $file, array $expectedErrors): void
+	{
+		$this->objectManagerLoader = null;
+		$this->analyse([$file], $expectedErrors);
+	}
+
+	/**
+	 * @return Iterator<mixed[]>
+	 */
+	public function ruleProvider(): Iterator
+	{
+		yield 'entity final constructor' => [
+			__DIR__ . '/data/EntityFinalConstructor.php',
+			[
+				[
+					'Constructor of class PHPStan\Rules\Doctrine\ORM\EntityFinalConstructor is final which can cause problems with proxies.',
+					12,
+				],
+			],
+		];
+
+		yield 'entity non-final constructor' => [
+			__DIR__ . '/data/EntityNonFinalConstructor.php',
+			[],
+		];
+
+		yield 'correct entity' => [
+			__DIR__ . '/data/MyEntity.php',
+			[],
+		];
+
+		yield 'non-entity final constructor' => [
+			__DIR__ . '/data/NonEntityFinalConstructor.php',
+			[],
+		];
+
+		yield 'final embeddable' => [
+			__DIR__ . '/data/FinalEmbeddable.php',
+			[],
+		];
+
+		yield 'non final embeddable' => [
+			__DIR__ . '/data/MyEmbeddable.php',
+			[],
+		];
+	}
+
+}

tests/Rules/Doctrine/ORM/data/EntityFinalConstructor.php

@@ -0,0 +1,14 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Doctrine\ORM;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * @ORM\Entity()
+ */
+class EntityFinalConstructor
+{
+	final public function __construct(string $x)
+	{}
+}

tests/Rules/Doctrine/ORM/data/EntityNonFinalConstructor.php

@@ -0,0 +1,17 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Doctrine\ORM;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * @ORM\Entity()
+ */
+class EntityNonFinalConstructor
+{
+	public function __construct()
+	{}
+
+	final public function foo()
+	{}
+}

tests/Rules/Doctrine/ORM/data/NonEntityFinalConstructor.php

@@ -0,0 +1,9 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Doctrine\ORM;
+
+class NonEntityFinalConstructor
+{
+	final public function __construct(string $x)
+	{}
+}