Wrong return type of \Imagick::mergeImageLayers()

[davidlienhard]

Hello everyone
I do have some issues with phpstan in combination with the method mergeImageLayers() from Imagick.
According to the Docs and my tests the method always returns an object of the type \Imagick.
But if I use some methods from Imagick on that object, phpstan reports that it's not possible to call that method on bool.
So phpstan wrongly guesses(?) the return type of \Imagick::mergeImageLayers() as bool.

I do have the following code for example: (This did not work on the playground because of missing Imagick class)

<?php
declare(strict_types = 1);

class magicktest
{
    public function imagick(): \Imagick
    {
        $img = new \Imagick(__DIR__."/image.jpg");
        $img = $img->mergeImageLayers(\Imagick::LAYERMETHOD_FLATTEN);
        var_dump($img);
        $img->setImageCompressionQuality(90);
        return $img;
    }
}

$m = new magicktest;
$m->imagick();

When I run the code (with PHP 8) i get the following result.

class Imagick#3 (0) {
}

But phpstan returns the following errors.

 ------ ---------------------------------------------------------- 
  11     Cannot call method setImageCompressionQuality() on bool.  
  12     Method magicktest::imagick() should return Imagick but returns bool.
 ------ ---------------------------------------------------------- 

Now I don't know, where the problem really is. Where does phpstan get the return value from \Imagick::mergeImageLayers()? Is this a bug in the code or does it just guess it? Is there a possibility to change this?

[ondrejmirtes]

Hi, phpstan.org reproduction works fine: https://phpstan.org/r/8e231f94-2f5d-47a4-9271-cef9062b95c3

You can follow this issue template (https://github.com/phpstan/phpstan/issues/new?assignees=&labels=&template=Function_signature_mismatch.md) which says:

Please send a pull request in phpstan/phpstan-src that updates file resources/functionMap.php instead. Thank you.

Here's the mistake. Please check whether more methods need fixing. Thanks.

[davidlienhard]

Hi @ondrejmirtes
Thanks for the quick reply. Weird, seems I did something wrong during tests on the playground.
I'll go through the functions and open a new PR.
Thanks!