PHPStan: Property with generic class does not specify its types: TKey, T

Question

I'm running PHPStan on a Symfony project where I have the following relation in a Doctrine entity:

/**
 * @ORM\OneToMany(targetEntity="App\Entity\Course\Slide", mappedBy="chapter", cascade={"persist"}, orphanRemoval=true)
 * @ORM\OrderBy({"listOrder" = "ASC"})
 *
 * @var ArrayCollection<Slide>
 */
private $slides;

Running analysis with rule level 6 I got the following message about the property (and its getter return type):

Property App\Entity\Course\Chapter::$slides with generic class Doctrine\Common\Collections\ArrayCollection does not specify its types: TKey, T
You can turn this off by setting checkGenericClassInNonGenericObjectType: false in your phpstan.neon.

My edit attempts only confused PHPStan, maybe because I'm not fully understanding generics here. But silencing the message just because I don't get it would be stupid.

What am I supposed to add or change in the PHPDoc ?

Please ask on GitHub next time: https://github.com/phpstan/phpstan/issues/new/choose — Ondřej Mirtes, Apr 25 '20 at 08:34
@OndřejMirtes I didn't want to bother you on GitHub as it is not a bug, but I'll remember (I often visit your GitHub btw). — AymDev, Apr 25 '20 at 09:49

score 28 · Accepted Answer · answered Apr 25 '20 at 08:34

28

ArrayCollection has two type variables: TKey and T. So ArrayCollection<Slide> isn't sufficient, you need something like ArrayCollection<int, Slide>.

answered Apr 25 '20 at 08:34

Ondřej Mirtes

5,054
25
36

Thank you. I think I understand, but just to be sure: the `int` type represents the foreign key type ? – AymDev Apr 25 '20 at 09:51
I'm not sure what Doctrine puts there as the iterable key type, you should try it out. – Ondřej Mirtes Apr 25 '20 at 19:48
Don't forget the space between coma and Slide! I lost one hour because of this space ^^ – Alexandre Tranchant Jul 14 '22 at 13:31

score 6 · Answer 2 · answered Oct 07 '20 at 11:11

6

It's

/**
 * @var ArrayCollection<int, Slide>
 */

Doing dump() on the parent entity shows that $slides is a 0-indexed array:

0 => App\Entity\Slide
1 => App\Entity\Slide

So it's an int, but not the entity's ID (since it isn't persisted yet).

Here's an in-depth article on generics by Ondřej Mirtes (=author of PhpStan): https://medium.com/@ondrejmirtes/generics-in-php-using-phpdocs-14e7301953

answered Oct 07 '20 at 11:11

Thomas Landauer

7,857
10
47
99

Thank you, I get it now. I have tried to read this post in the past but did not understand, now it clicks ! Going to refactor some code with generics – AymDev Oct 07 '20 at 15:50

PHPStan: Property with generic class does not specify its types: TKey, T

2 Answers2