Error Identifier: class.extendsFinalByPhpDoc

Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.

Code example #

<?php declare(strict_types = 1);

/**
 * @final
 */
class ParentClass
{
}

class ChildClass extends ParentClass
{
}

Why is it reported? #

The class being extended is marked as @final in its PHPDoc. While PHP does not enforce this at runtime (unlike the native final keyword), the @final annotation signals that the class author considers it part of the API contract that the class should not be extended. Extending it may lead to breaking changes in the future when the class is modified.

Unlike the native final keyword which causes a PHP fatal error, @final is a soft constraint enforced by static analysis tools. This is why the error is ignorable.

How to fix it #

Use composition instead of inheritance:

 <?php declare(strict_types = 1);
 
 /**
  * @final
  */
 class ParentClass
 {
+	public function doSomething(): void
+	{
+	}
 }

-class ChildClass extends ParentClass
+class ChildClass
 {
+	public function __construct(
+		private ParentClass $parent,
+	) {
+	}
+
+	public function doSomething(): void
+	{
+		$this->parent->doSomething();
+	}
 }

If extending the class is intentional and the @final annotation should not apply, the error can be suppressed in the PHPStan configuration.

How to ignore this error #

You can use the identifier class.extendsFinalByPhpDoc to ignore this error using a comment:

// @phpstan-ignore class.extendsFinalByPhpDoc
codeThatProducesTheError();

You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:

parameters:
	ignoreErrors:
		-
			identifier: class.extendsFinalByPhpDoc

Rules that report this error #

PHPStan\Rules\Classes\ExistingClassInClassExtendsRule [1]

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