property.private - Phpstan

Code example

php

<?php declare(strict_types = 1);

class ParentClass
{
	private string $secret = 'hidden';
}

class ChildClass extends ParentClass
{
	public function getSecret(): string
	{
		return $this->secret; // ERROR: Access to private property $secret of parent class ParentClass.
	}
}

Why is it reported?

The code attempts to access a private property from outside the class where it is declared. Private properties are only accessible within the class that defines them -- not from subclasses, not from parent classes, and not from outside code. Attempting to access a private property from a child class will result in accessing an undefined property rather than the parent's private property.

How to fix it

Change the property visibility to protected if it should be accessible by subclasses:

diff-php

 <?php declare(strict_types = 1);

 class ParentClass
 {
-	private string $secret = 'hidden';
+	protected string $secret = 'hidden';
 }

 class ChildClass extends ParentClass
 {
 	public function getSecret(): string
 	{
 		return $this->secret;
 	}
 }

Or provide a getter method in the parent class:

diff-php

 <?php declare(strict_types = 1);

 class ParentClass
 {
 	private string $secret = 'hidden';
+
+	protected function getSecret(): string
+	{
+		return $this->secret;
+	}
 }

 class ChildClass extends ParentClass
 {
 	public function getSecret(): string
 	{
-		return $this->secret;
+		return parent::getSecret();
 	}
 }