Adding an instance of a class which has an __invoke method

[willemwollebrants]

I'm not sure if this is expected behavior or not, but here goes:

When you add an instance of a class which has an __invoke method, the DefinitionFactory sees this as a callable, so it gets added as a CallableDefinition. As a consequence of this, when you try to get the $concrete it does not return the instance, but whatever the __invoke method returns.

Here's an example to make it a bit clearer

I think this might be a bug, because changing the innards of a class should probably not change what the container returns. If my thinking is correct, the fix would probably be handling objects which are not instances of Callable like any other undefineable item and just add them as an arbitrary value/instance (= like here.

I'm more than willing to PR this, but I'd rather make sure this is indeed a bug and not by design, because I can imagine being able to use __invoke has its uses too.

[philipobenito]

@willemwollebrants yes this is a bug/oversight, the decision was made to handle is_callable classes in this way to allow for some nice organisation, however, as you point out it should not be to the detriment of a class that happens to have an __invoke method. Regardless of whether it is classified as a bug or not, this is unfortunately a BC break to fix and would have to aim at v3.0.0, there are a couple of smaller changes that are planned that also need to target v3.0.0 so I can either pick it up with those or I'd be happy to look at a PR to bring in.

[khelle]

I believe it should be marked as bug, because the behaviour right now is inconsistent when using autowiring. Trying to make object from class that has __invoke method from container with autowiring treats the constructed object as object. On the other hand if concrete definition is provided, then container treats it as callable, meaning result of get() method on such classes is nondeterministic.

[philipobenito]

@hannesvdvreken @localheinz @khelle I'm developing 3.0.0 right now and struggling to come up with a good solution to this. Any thoughts?

My only clean solution is ignoring classes implementing __invoke as factories completely but I'd rather not do that.

[philipobenito]

Handled in 421d774 for release in 3.0.0.

Provided ClassName argument object to ensure that any class wrapped will be resolved as a class and not a callable.

[hannesvdvreken]

It's an exceptional case, and there is a simple way of resolving an invokable object.
So I wouldn't consider it a bug, and won't spend time/lines of code to make a BC change for this small case.

[philipobenito]

I think the solution I've implemented works for this, won't be changing default behaviour though.

[hannesvdvreken]

👍

[SammyK]

FWIW, I was having this same issue in league/container version 2.4.1 when trying to register league/commonmark (0.17.5) into the container since League\CommonMark\CommonMarkConverter has an __invoke() method.

<?php

namespace Foo\Markdown;

use League\CommonMark\CommonMarkConverter;
use League\Container\ServiceProvider\AbstractServiceProvider;

class CommonMarkProvider extends AbstractServiceProvider
{
    protected $provides = [
        CommonMarkConverter::class,
    ];

    public function register(): void
    {
        $converter = new CommonMarkConverter;
        $this->getContainer()->share(CommonMarkConverter::class, $converter);
    }
}

Fails with error:

PHP Fatal error:  Uncaught ArgumentCountError: Too few arguments to function League\CommonMark\Converter::__invoke(), 0 passed and exactly 1 expected in /var/www/html/vendor/league/commonmark/src/Converter.php:73

My workaround was to make a wrapper for CommonMarkConverter and register the wrapper in the container:

<?php

namespace Foo\Markdown;

use League\CommonMark\CommonMarkConverter;

class CommonMarkWrapper
{
    private $converter;

    public function __construct()
    {
        $this->converter = new CommonMarkConverter;
    }

    public function toHtml(string $markdown): string
    {
        return $this->converter->convertToHtml($markdown);
    }
}

I hope that helps others who run into this issue. :)

[localheinz]

@SammyK

I had exactly (!) the same issue a while ago.