Error Identifier: unset.possiblyHookedProperty

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);

class User
{
	public string $name;

	public function reset(): void
	{
		unset($this->name);
	}
}

Why is it reported? #

Starting with PHP 8.4, properties can have hooks (get/set). Unsetting a property that is not private, not final, and belongs to a non-final class is reported because a subclass could add hooks to that property. Unsetting a hooked property is not allowed in PHP, so the unset() call could fail at runtime if a child class introduces hooks.

How to fix it #

Mark the property or class as final to prevent subclasses from adding hooks, or mark the property as private.

 <?php declare(strict_types = 1);
 
 class User
 {
-	public string $name;
+	public final string $name;

 	public function reset(): void
 	{
 		unset($this->name);
 	}
 }

Alternatively, mark the entire class as final:

 <?php declare(strict_types = 1);
 
-class User
+final class User
 {
 	public string $name;

 	public function reset(): void
 	{
 		unset($this->name);
 	}
 }

How to ignore this error #

You can use the identifier unset.possiblyHookedProperty to ignore this error using a comment:

// @phpstan-ignore unset.possiblyHookedProperty
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: unset.possiblyHookedProperty

Rules that report this error #

PHPStan\Rules\Variables\UnsetRule [1]

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