1.2.485. Friend Attribute

A method or class can supply via a #[Friend] attribute a list of classes. Only these classes can call the method. This is loosely based on the C++ friend feature.

  • Multiple classes can be specified. E.g. #[Friend(Foo::class, Bar::class)]

  • A class can have a #[Friend] attribute, classes listed here are applied to every method.

  • The #[Friend] attribute is additive. If a class and a method have the #[Friend] the method can be called from any of the classes listed. E.g.

  • This is is currently limited to method calls (including __construct).

  • The Attribute is limited to the exact classes, the family hierarchy is not searched.

  • Multiple attributes can be specified to add more classes. E.g. #[Friend(Foo::class)] #[Friend(Bar::class)]

Based on the specificiations from Dave Liddament.

<?php

class Person
{
    #[Friend(PersonBuilder::class)]
    public function __construct()
    {
        // Some implementation
    }
}


class PersonBuilder
{
    public function build(): Person
    {
        $person = new Person(): // OK as PersonBuilder is allowed to call Person's construct method.
        // set up Person
        return $person;
    }
}


// ERROR Call to Person::__construct is not from PersonBuilder
$person = new Person();

?>

See also Friend and php-language-extension.

1.2.485.1. Connex PHP features

1.2.485.1.1. Suggestions

  • Add the reported classes as friend to the original class

  • Remove the call to the class from the reported classes

1.2.485.1.2. Specs

Short name

Attributes/Friend

Rulesets

All, Attributes, Changed Behavior

Exakat since

2.6.2

PHP Version

With PHP 8.0 and more recent

Severity

Minor

Time To Fix

Quick (30 mins)

Precision

Very high

Available in

Entreprise Edition, Exakat Cloud