Add ClassMustBeFinalRule and remove ForbiddenInheritanceRule

Author: Kocal

README.md

@@ -21,6 +21,63 @@ Each rule can be enabled individually by adding it to your `phpstan.dist.neon` c
 > [!NOTE]
 > All these rules also apply to LiveComponents (classes annotated with `#[AsLiveComponent]`).
 
+### ClassMustBeFinalRule
+
+Enforces that all Twig Component classes must be declared as `final`.
+This prevents inheritance and promotes composition via traits, ensuring better code maintainability and avoiding tight coupling between components.
+
+```yaml
+rules:
+    - Kocal\PHPStanSymfonyUX\Rules\TwigComponent\ClassMustBeFinalRule
+```
+
+```php
+// src/Twig/Components/Alert.php
+namespace App\Twig\Components;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+class Alert
+{
+    public string $message;
+}
+```
+
+```php
+// src/Twig/Components/Alert.php
+namespace App\Twig\Components;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+abstract class Alert
+{
+    public string $message;
+}
+```
+
+:x:
+
+<br>
+
+```php
+// src/Twig/Components/Alert.php
+namespace App\Twig\Components;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+final class Alert
+{
+    public string $message;
+}
+```
+
+:+1:
+
+<br>
+
 ### ClassNameShouldNotEndWithComponentRule
 
 Forbid Twig Component class names from ending with "Component" suffix, as it creates redundancy since the class is already identified as a component through the `#[AsTwigComponent]` attribute.
@@ -230,76 +287,6 @@ final class Alert
 
 <br>
 
-### ForbiddenInheritanceRule
-
-Forbids the use of class inheritance in Twig Components. Composition via traits should be used instead.
-This promotes better code reusability and avoids tight coupling between components.
-
-> [!TIP]
-> Another alternative is to use [Class Variant Authority](https://symfony.com/bundles/ux-twig-component/current/index.html#component-with-complex-variants-cva) to create variations of a base component without inheritance or traits,
-> for example `<twig:Alert variant="success"></twig:Alert>` instead of `<twig:AlertSuccess></twig:AlertSuccess>`.
-
-```yaml
-rules:
-    - Kocal\PHPStanSymfonyUX\Rules\TwigComponent\ForbiddenInheritanceRule
-```
-
-```php
-// src/Twig/Components/Alert.php
-namespace App\Twig\Components;
-
-use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
-
-abstract class BaseComponent
-{
-    public string $name;
-}
-
-#[AsTwigComponent]
-class Alert extends BaseComponent
-{
-}
-```
-
-:x:
-
-<br>
-
-```php
-// src/Twig/Components/Alert.php
-namespace App\Twig\Components;
-
-use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
-
-trait CommonComponentTrait
-{
-    public string $name;
-}
-
-#[AsTwigComponent]
-final class Alert
-{
-    use CommonComponentTrait;
-}
-```
-
-```php
-// src/Twig/Components/Alert.php
-namespace App\Twig\Components;
-
-use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
-
-#[AsTwigComponent]
-final class Alert
-{
-    public string $name;
-}
-```
-
-:+1:
-
-<br>
-
 ### MethodsShouldBePublicOrPrivateRule
 
 Enforces that all methods in Twig Components are either public or private, but not protected.

src/Rules/TwigComponent/ForbiddenInheritanceRule.php renamed to src/Rules/TwigComponent/ClassMustBeFinalRule.php

@@ -16,7 +16,7 @@
 /**
  * @implements Rule<Class_>
  */
-final class ForbiddenInheritanceRule implements Rule
+final class ClassMustBeFinalRule implements Rule
 {
     public function getNodeType(): string
     {
@@ -29,12 +29,20 @@ public function processNode(Node $node, Scope $scope): array
             return [];
         }
 
-        if ($node->extends !== null) {
+        if ($node->isAbstract()) {
             return [
-                RuleErrorBuilder::message('Using class inheritance in a Twig component is forbidden, use traits for composition instead.')
-                    ->identifier('symfonyUX.twigComponent.forbiddenClassInheritance')
-                    ->line($node->extends->getLine())
-                    ->tip('Consider using traits to share common functionality between Twig components.')
+                RuleErrorBuilder::message('Twig component class must be final, not abstract.')
+                    ->identifier('symfonyUX.twigComponent.classMustBeFinal')
+                    ->tip('Make the class final and use traits for composition instead of inheritance.')
+                    ->build(),
+            ];
+        }
+
+        if (! $node->isFinal()) {
+            return [
+                RuleErrorBuilder::message('Twig component class must be final.')
+                    ->identifier('symfonyUX.twigComponent.classMustBeFinal')
+                    ->tip('Add the "final" keyword to the class declaration to prevent inheritance.')
                     ->build(),
             ];
         }

tests/Rules/TwigComponent/ClassMustBeFinalRule/ClassMustBeFinalRuleTest.php

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule;
+
+use Kocal\PHPStanSymfonyUX\Rules\TwigComponent\ClassMustBeFinalRule;
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<ClassMustBeFinalRule>
+ */
+final class ClassMustBeFinalRuleTest extends RuleTestCase
+{
+    public function testViolations(): void
+    {
+        $this->analyse(
+            [__DIR__ . '/Fixture/InvalidNonFinalTwigComponent.php'],
+            [
+                [
+                    'Twig component class must be final.',
+                    9,
+                    'Add the "final" keyword to the class declaration to prevent inheritance.',
+                ],
+            ]
+        );
+
+        $this->analyse(
+            [__DIR__ . '/Fixture/InvalidNonFinalLiveComponent.php'],
+            [
+                [
+                    'Twig component class must be final.',
+                    9,
+                    'Add the "final" keyword to the class declaration to prevent inheritance.',
+                ],
+            ]
+        );
+
+        $this->analyse(
+            [__DIR__ . '/Fixture/InvalidAbstractTwigComponent.php'],
+            [
+                [
+                    'Twig component class must be final, not abstract.',
+                    9,
+                    'Make the class final and use traits for composition instead of inheritance.',
+                ],
+            ]
+        );
+
+        $this->analyse(
+            [__DIR__ . '/Fixture/InvalidAbstractLiveComponent.php'],
+            [
+                [
+                    'Twig component class must be final, not abstract.',
+                    9,
+                    'Make the class final and use traits for composition instead of inheritance.',
+                ],
+            ]
+        );
+    }
+
+    public function testNoViolations(): void
+    {
+        $this->analyse(
+            [__DIR__ . '/Fixture/NotAComponent.php'],
+            []
+        );
+
+        $this->analyse(
+            [__DIR__ . '/Fixture/ValidTwigComponent.php'],
+            []
+        );
+
+        $this->analyse(
+            [__DIR__ . '/Fixture/ValidLiveComponent.php'],
+            []
+        );
+    }
+
+    public static function getAdditionalConfigFiles(): array
+    {
+        return [__DIR__ . '/config/configured_rule.neon'];
+    }
+
+    protected function getRule(): Rule
+    {
+        return self::getContainer()->getByType(ClassMustBeFinalRule::class);
+    }
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/InvalidAbstractLiveComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
+
+#[AsLiveComponent]
+abstract class InvalidAbstractLiveComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/InvalidAbstractTwigComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+abstract class InvalidAbstractTwigComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/InvalidNonFinalLiveComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
+
+#[AsLiveComponent]
+class InvalidNonFinalLiveComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/InvalidNonFinalTwigComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+class InvalidNonFinalTwigComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/NotAComponent.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+class NotAComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/ValidLiveComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
+
+#[AsLiveComponent]
+final class ValidLiveComponent
+{
+}

tests/Rules/TwigComponent/ClassMustBeFinalRule/Fixture/ValidTwigComponent.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kocal\PHPStanSymfonyUX\Tests\Rules\TwigComponent\ClassMustBeFinalRule\Fixture;
+
+use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;
+
+#[AsTwigComponent]
+final class ValidTwigComponent
+{
+}