Error Identifier: property.notReadable

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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);

interface HasValue
{
	public int $value { get; }
}

class Foo implements HasValue
{
	private int $stored = 0;

	public int $value {
		set {
			$this->stored = $value;
		}
	}
}

Why is it reported? #

When a child class overrides a property from a parent class or interface, it must preserve the readability contract. If the parent property is readable (has a get hook or is a regular property), the overriding property must also be readable. Removing readability from an overriding property would break the Liskov Substitution Principle – code that expects to read the property based on the parent type would fail.

In the example above, the interface HasValue declares $value as readable (get), but the implementing class defines only a set hook that stores to a different field. This makes the property virtual and write-only, violating the readability contract.

This rule applies to PHP 8.4+ property hooks.

How to fix it #

Add a get hook to the overriding property so it remains readable:

 class Foo implements HasValue
 {
 	private int $stored = 0;

 	public int $value {
+		get {
+			return $this->stored;
+		}
 		set {
 			$this->stored = $value;
 		}
 	}
 }

Non-ignorable error #

This error cannot be ignored using @phpstan-ignore or the ignoreErrors configuration. Non-ignorable errors indicate code that would cause a crash or a fatal error at runtime, or a fundamental problem in the analysed code that must be addressed.

Rules that report this error #

• PHPStan\Rules\Properties\OverridingPropertyRule [1]