False positive in PHPStan 1.4.8 with assertNotSame with instances of the same class

[oliverklee]

Using phpstan/phpstan-phpunit 1.0.0 and phpstan/phpstan 1.4.8, the following code creates a false positive:

namespace OliverKlee\Oelib\Tests\Unit\Templating;

use Nimut\TestingFramework\TestCase\UnitTestCase;
use OliverKlee\Oelib\Templating\Template;
use OliverKlee\Oelib\Templating\TemplateRegistry;

class TemplateRegistryTest extends UnitTestCase
{
    /**
     * @test
     */
    public function getForExistingTemplateFileNameCalledTwoTimesReturnsNewInstance(): void
    {
        self::assertNotSame(
            TemplateRegistry::get('EXT:oelib/Tests/Functional/Fixtures/Template.html'),
            TemplateRegistry::get('EXT:oelib/Tests/Functional/Fixtures/Template.html')
        );
    }
}

This is the error (with different line numbers):

 ------ --------------------------------------------------------------------------------------------------------------------------------------------------------- 
  Line   Tests/Unit/Templating/TemplateRegistryTest.php                                                                                                           
 ------ --------------------------------------------------------------------------------------------------------------------------------------------------------- 
  69     Call to static method PHPUnit\Framework\Assert::assertNotSame() with OliverKlee\Oelib\Templating\Template and OliverKlee\Oelib\Templating\Template will  
         always evaluate to false.                                                                                                                                
  91     Call to static method PHPUnit\Framework\Assert::assertNotSame() with OliverKlee\Oelib\Templating\Template and OliverKlee\Oelib\Templating\Template will  
         always evaluate to false.                                                                                                                                
 ------ --------------------------------------------------------------------------------------------------------------------------------------------------------- 

This problem is new with PHPStan 1.4.8 (as it did no occur with PHPStan 1.4.7).

You can find the complete build with the problem at oliverklee/ext-oelib#904.

(I was not able to use the PHPStan playground for this as I currently do not know of any way of including PHPUnit in it: https://phpstan.org/r/c7fa7bda-1024-45c3-957d-7b91de41b844)

[ondrejmirtes]

/cc @herndlm Probably worth changing the code to only work for Variable node?

[herndlm]

🤦‍♂️ weird, I thought this should not happen because very similar looking comparisons in https://github.com/phpstan/phpstan-src/blob/1.4.8/tests/PHPStan/Rules/Comparison/data/impossible-method-call.php#L75 and https://github.com/phpstan/phpstan-src/blob/1.4.8/tests/PHPStan/Rules/Comparison/data/impossible-method-call.php#L87 are fine

/cc @herndlm Probably worth changing the code to only work for Variable node?

sounds like a solution. somehow reproducing that in PHPStan directly would be nice too when I try to fix it ;)

[herndlm]

Oh look at that, apparently only those static factory-like methods are problems. See phpstan/phpstan-webmozart-assert#122. I'm not sure anymore if limiting it to Variable nodes is the right solution. Maybe there's a bug hidden somewhere else.
I can continue debugging this later today.

[ondrejmirtes]

It's not a problem for New_ thanks to: https://github.com/phpstan/phpstan-src/blob/156cb69be747b7821275803717ef840fae636602/src/Analyser/TypeSpecifier.php#L976-L978

But it's a problem for anything that can be remembered in SpecifiedTypes by TypeSpecifier.

[herndlm]

Right, while I was doing a quick test I was actually comparing the type with a node class and thought something is weird. Limiting it to Variable nodes seems to be doing the trick. Give me a couple of minutes..

[oliverklee]

@herndlm Thanks for working on this! ❤️

[herndlm]

Looks like the same problem existed in a truthy scope with === already. I'm trying to fix that too, and I'm having a hard time creating failing tests for the falsey scope. Which is why this will take a bit longer than a couple of minutes :)

[herndlm]

@ondrejmirtes do we need a regression test here? or better: do you want one? :)

[ondrejmirtes]

Yes, please send it 😊

[ondrejmirtes]

Fixed in PHPStan 1.4.9 https://github.com/phpstan/phpstan/releases/tag/1.4.9

[oliverklee]

Thanks, @ondrejmirtes and @herndlm! ❤️

[github-actions]

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