unset.readOnlyPropertyByPhpDoc - Phpstan

Code example

php

<?php declare(strict_types = 1);

class Foo
{
	/** @readonly */
	public int $value;

	public function __construct(int $value)
	{
		$this->value = $value;
	}

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

Why is it reported?

The code attempts to unset() a property that is marked as @readonly in PHPDoc. Readonly properties should not be unset because they are intended to be immutable after initialization.

How to fix it

Do not unset the readonly property. If you need to reset it, consider restructuring your code:

diff-php

 <?php declare(strict_types = 1);

 class Foo
 {
 	/** @readonly */
 	public int $value;

 	public function __construct(int $value)
 	{
 		$this->value = $value;
 	}

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