False Postive: Aliased PHP 8.0 Attributes on Class properties leading to "Namespaced classes/interfaces/traits should be referenced with use statements"

Created on 13 December 2023, 11 months ago
Updated 5 May 2024, 7 months ago

Problem/Motivation

When having a class with Aliased PHP Attributes attached to properties we get the following phpcs error

Namespaced classes/interfaces/traits should be referenced with use statements

<?php

use Symfony\Component\Validator\Constraints as Assert;

class Foo {

  #[Assert\NotBlank]
  /**
   * Bar property.
   *
   * @var bool
   */
  private bool $bar;

This is a very commong Symfony community drive way to add assertion using a Namespace alias Assert.

Steps to reproduce

run phpcs against

<?php

use Symfony\Component\Validator\Constraints as Assert;

/**
 * Foo class description.
 */
class Foo {

  #[Assert\NotBlank]
  /**
   * Bar property.
   *
   * @var bool
   */
  private bool $bar;

}

Workaround

A working workaround for now is to remove the namespace alias.

<?php

use Symfony\Component\Validator\Constraints\NotBlank;

/**
 * Foo class description.
 */
class Foo {

  #[NotBlank]
  /**
   * Bar property.
   *
   * @var bool
   */
  private bool $bar;

}

Proposed resolution

  • Having a sniffer that handle PHP 8.0 Attribute properly

Remaining tasks

🐛 Bug report
Status

Active

Version

8.3

Component

Coder Sniffer

Created by

🇨🇭Switzerland wengerk Lausanne

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  • PHP 8.0

    The issue particularly affects sites running on PHP version 8.0.0 or later.

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Comments & Activities

  • Issue created by @wengerk
  • Status changed to Active 9 months ago
  • 🇦🇹Austria klausi 🇦🇹 Vienna

    Thanks for reporting!

    Not sure we should do something here as the Drupal coding standards say: "PHP allows classes to be aliased when they are imported into a namespace. In general that should only be done to avoid a name collision." https://www.drupal.org/docs/develop/coding-standards/namespaces#s-class-...

    In your example there is no name collision. I don't think it is good practice from Symfony to alias "Constraints" to "Assert", which can be super confusing as there is no Assert namespace anywhere.

    Would like to hear more opinions on this!

  • 🇨🇭Switzerland wengerk Lausanne

    Many thanks for your consideration and answer.
    I totally understand your point of view.
    I still reckon using aliases for Attribute is a smart move, just like Symfony does. Let me proceed with why.

    There's this discussion in the community (https://github.com/symfony/symfony/discussions/45525) that backs up this convention.
    I'll sum up one of the responses below for easier reading:

    Having alias provides additional context to what you're doing, especially when you're in a class that might be using attributes from multiple packages. Suppose you have a class User with validation constraints and Serialization, it wouldn't be all that farfetched to have a property definition like this one:

    class User
    {
        #[Assert\Email]
        #[Serializer\Groups(['list'])]
        public string $email;
    }
    

    With the aliased imports, you know where each of the attributes is coming from and what their purpose is (validation constraint, serialization group configuration, etc ...). If you take away the imports, there's a bit more ambiguity with each attribute:

    class User
    {
        #[Email]
        #[Groups(['list'])]
        public string $email;
    }
    

    Hope this helps explain why having aliases makes sense.
    Keep up the awesome work with the drupal/coder!

  • 🇦🇹Austria klausi 🇦🇹 Vienna

    Thanks a lot for the explanation.

    I would argue that your example is an indication of a code smell. Never name a class "Email", that is a very bad name on its own as it is very ambiguous. You should not solve bad naming by using aliases all over the place when your class is used.

    Yes, that would mean repeating the namespace in the class name, but that is totally fine and much better. Don't optimize your fully qualified class name for shortness; it still should convey meaning on its own.

    What would be a good example for the Email class name here? In my opinion: "Symfony\Component\Validator\Constraints\EmailConstraint", then "EmailConstraint" is much clearer that this is a validation constraint.

    Same for serialization groups. Is "Groups" a good class name? Probably not. I like "SerializationGroups" much more.

    Doing that consistently suddenly all your aliasing problems go away because you now you actually have good class names that mean something.

    So much for my rant on this topic :-) I'm still open to support aliasing in Coder for attributes, since we probably can't convince the Symfony folks to use meaningful class names.

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