class.serializable - Phpstan

Code example

php

<?php declare(strict_types = 1);

class Foo implements \Serializable
{
	public function serialize(): ?string
	{
		return serialize([]);
	}

	public function unserialize(string $data): void
	{
	}
}

Why is it reported?

A non-abstract class implements the Serializable interface but does not implement the __serialize() and/or __unserialize() magic methods. Since PHP 8.1, the Serializable interface is deprecated in favour of the __serialize() and __unserialize() magic methods. Classes that implement Serializable without also providing the magic methods will emit a deprecation notice.

How to fix it

Add the __serialize() and __unserialize() magic methods:

diff-php

 <?php declare(strict_types = 1);

 class Foo implements \Serializable
 {
 	public function serialize(): ?string
 	{
 		return serialize([]);
 	}

 	public function unserialize(string $data): void
 	{
 	}

+	public function __serialize(): array
+	{
+		return [];
+	}
+
+	public function __unserialize(array $data): void
+	{
+	}
 }

Or better yet, remove the Serializable interface entirely and rely solely on the magic methods:

diff-php

 <?php declare(strict_types = 1);

-class Foo implements \Serializable
+class Foo
 {
-	public function serialize(): ?string
-	{
-		return serialize([]);
-	}
-
-	public function unserialize(string $data): void
-	{
-	}
-
 	public function __serialize(): array
 	{
 		return [];
 	}

 	public function __unserialize(array $data): void
 	{
 	}
 }