Access to an undefined property object::$foo on instances of \stdClass

[andreasciamanna]

When declaring a new instance of stdClass and trying to set the value of a property of that instance, I get Access to an undefined property object::$foo.

Demo of the issue: https://phpstan.org/r/e4ecbdf9-83e6-45a5-b819-852353a38478

\stdClass is a valid type and I must be able to set any property I want.

I don't understand why PHPStan complains about it.

Any idea on how to fix this without ignoring the error (a solution I'd like to avoid)?

[ondrejmirtes]

PHPStan doesn't know that $type_info is stdClass, just object. See: https://phpstan.org/r/8af5033b-c0f9-4e5e-90ea-e608fc12fd72

[andreasciamanna]

Ok, there's definitely something wrong with my eyes: PHPStan was telling me the line, and yet, I was looking at a different line :)

I'm writing this more as a record for the future me (or others with a similar issue).

I thought PHPStan was complaining about $new_type not $type_info.
$type_info, or better, $this->post_types, in my original code, is declared via PHPDoc as /** @var array<string, \WP_Post_Type> */

PHPStan should see that $type_info is an instance of \WP_Post_Type and not an "object".

Something is changing the type of the property, and it's $this->post_types = apply_filters( 'wpml_get_translatable_types', $this->post_types ); (apply_filters returns mixed).

So, it's a sign that the value returned by apply_filters must be validated (and cast to the right type).

Thanks!

[ondrejmirtes]

the value returned by apply_filters must be validated (and cast to the right type).

Make sure to check out generics for that purpose :) https://phpstan.org/blog/generics-in-php-using-phpdocs

[andreasciamanna]

Validation is on the way.

Generics my code must be kept compatible down to PHP 5.6, so I have to deal with compromises :)

[ondrejmirtes]

@andreasciamanna In PHP you write generics in PHPDocs, so there's no problem with compatibility.

[andreasciamanna]

Oh, I see!

I thought it did require to return type-hints.

Thanks!