OverridingPropertyRule - check for final

Author: ondrejmirtes

src/Reflection/Php/PhpPropertyReflection.php

@@ -234,7 +234,14 @@ public function isAbstract(): TrinaryLogic
 
 	public function isFinal(): TrinaryLogic
 	{
-		return TrinaryLogic::createFromBoolean($this->reflection->isFinal());
+		if ($this->reflection->isFinal()) {
+			return TrinaryLogic::createYes();
+		}
+		if ($this->reflection->isPrivate()) {
+			return TrinaryLogic::createNo();
+		}
+
+		return TrinaryLogic::createFromBoolean($this->isPrivateSet());
 	}
 
 	public function isVirtual(): TrinaryLogic

src/Rules/Properties/OverridingPropertyRule.php

@@ -102,6 +102,18 @@ public function processNode(Node $node, Scope $scope): array
 			))->identifier('property.visibility')->nonIgnorable()->build();
 		}
 
+		if ($prototype->isFinal()->yes()) {
+			$errors[] = RuleErrorBuilder::message(sprintf(
+				'Property %s::$%s overrides final property %s::$%s.',
+				$classReflection->getDisplayName(),
+				$node->getName(),
+				$prototype->getDeclaringClass()->getDisplayName(),
+				$node->getName(),
+			))->identifier('property.parentPropertyFinal')
+				->nonIgnorable()
+				->build();
+		}
+
 		$typeErrors = [];
 		$nativeType = $node->getNativeType();
 		if ($prototype->hasNativeType()) {

tests/PHPStan/Rules/Properties/OverridingPropertyRuleTest.php

@@ -5,6 +5,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Testing\RuleTestCase;
 use function sprintf;
+use const PHP_VERSION_ID;
 
 /**
  * @extends RuleTestCase<OverridingPropertyRule>
@@ -171,4 +172,31 @@ public function testBug7692(): void
 		$this->analyse([__DIR__ . '/data/bug-7692.php'], []);
 	}
 
+	public function testFinal(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4.');
+		}
+
+		$this->reportMaybes = true;
+		$this->analyse([__DIR__ . '/data/overriding-final-property.php'], [
+			[
+				'Property OverridingFinalProperty\Bar::$a overrides final property OverridingFinalProperty\Foo::$a.',
+				21,
+			],
+			[
+				'Property OverridingFinalProperty\Bar::$b overrides final property OverridingFinalProperty\Foo::$b.',
+				23,
+			],
+			[
+				'Property OverridingFinalProperty\Bar::$c overrides final property OverridingFinalProperty\Foo::$c.',
+				25,
+			],
+			[
+				'Property OverridingFinalProperty\Bar::$d overrides final property OverridingFinalProperty\Foo::$d.',
+				27,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/overriding-final-property.php

@@ -0,0 +1,29 @@
+<?php // lint >= 8.4
+
+namespace OverridingFinalProperty;
+
+class Foo
+{
+
+	final public $a;
+
+	final protected $b;
+
+	public private(set) $c;
+
+	protected private(set) $d;
+
+}
+
+class Bar extends Foo
+{
+
+	public $a;
+
+	public $b;
+
+	public $c;
+
+	public $d;
+
+}