[TwigComponents] Using FQCN to load component leads to component being loaded anonymously

[janopae]

According to the docs, you can use both, the actual class name and a special : syntax to load a twig component. This worked until da0537d:

Internally, the ComponentFactory would use the : syntax to store config per component, but it also has a $this->classMap, which maps the actual class name to the : version. Before doing anything, the ComponentFactory would ask the classMap to resolve the loaded component name, only then it would proceed with loading.

This changed in da0537d: Now, it first tries to load the component with the provided name directly, and if that doesn't work, it will load the component anonymously (which means: the class will be ignored, only the Twig template will be loaded).

There is still code that uses the classMap, but that will only be executed if the template can't be loaded anonymously. Which I think will never happen, because any component has a Twig template? At least, it will never happen if the component has a Twig template, because unlike ComponentFactory after da0537d, ComponentTemplateFinder is able to resolve FQCNs.

It turned out I was wrong about Twig always being able to load a template for an FQCN: It is only able to load a template anonymously for the FQCN if the template path equals the FQCN (with backslashes replaced with slashes and ignoring the file extension). This is the case for all templates in my project, but I think it is not for the Symfony default. Because this issue only occurs in that case, it is not easy to reproduce. I created a reproducer in this repo: https://github.com/janopae/reproduce-symfony-ux-540

So essentially, identifying the component by class name now leads to the class being ignored. Given the tags containing da0537d, this affects all versions from 2.20.0 to 2.31.0.

[Kocal]

Hi, and thanks for rising this issue!

I'm having some difficulties to understand the problem:

• I don't see in the documentation about rendering the component with the FQCN
• I created a file \App\Twig\Components\Foo\Bar with the following code, and it correctly renders with {{ component('App\\Twig\\Components\\Foo\\Bar') }} and <twig:Bar />

<?php

declare(strict_types=1);

namespace App\Twig\Components\Foo;

use Symfony\UX\TwigComponent\Attribute\AsTwigComponent;

#[AsTwigComponent(name: 'Bar', template: 'components/bar.html.twig')]
final readonly class Bar
{

}

Can you provide some reproducer? Thanks!

[smnandre]

I'm not sure the code i changed has the impact you say it has ... Like @Kocal, I'd be happy to see a concrete example, right now I'm not sure to understand the problem.. and how my PR would change anything here

[janopae]

At least this part of the docs suggest using FQCN is possible: https://symfony.com/bundles/ux-twig-component/current/index.html#test-helpers

I'm sorry, creating a reproducer revealed that I was wrong assuming

ComponentTemplateFinder is able to resolve FQCNs

This is not always true – it depends on the naming of the component and the template.

So the bug only occurs when the FQCN of the component class can be resolved to a template path by Twig.

For the naming scheme I use in my application, this is always the case, because https://github.com/twigphp/Twig/blob/8074ddcab8e0a82a19213c8f4e546359dd10e6ed/src/Loader/FilesystemLoader.php#L239 replaces the \ with /, and I name the templates exactly the way I name components.

Here's the reproducer: https://github.com/janopae/reproduce-symfony-ux-540

[smnandre]

At least this part of the docs suggest using FQCN is possible:

No it's only some DX sugar while testing.... components are registered/resolved via a "name" and not more sorry :|

[janopae]

No it's only some DX sugar while testing....

But it's broken since da0537d, as my reproducer shows.

Edit: Should I add to the issue description that this only affects DX to avoid confusion?

components are registered/resolved via a "name" and not more sorry :|

Then what is ComponentFactory::classMap for?

There is no difference between loading a component via {{ component(name, data) }} or calling $this->renderTwigComponent($name, $data) in a TestCase. When you call renderTwigComponent, rendering a template with {{ component(name, data) }} is actually all that happens in the background! There was never a "DX sugar" extra step to resolve FQCNs. Look at the code, this is all that happens:

ux/src/TwigComponent/src/Test/InteractsWithTwigComponents.php

Lines 42 to 49 in 0c63ac0

	return new RenderedComponent(
	self::getContainer()->get('twig')
	->createTemplate('{{ component(name, data) }}')
	->render([
	'name' => $name,
	'data' => $data,
	])
	);

The FQCNs used to get resolved inside ComponentFactory using ComponentFactory::classMap.

[smnandre]

Here's the reproducer: https://github.com/janopae/reproduce-symfony-ux-540

Thanks, i'll have a look tonight to understand better, and try to see what's at play here 👍

[smnandre]

Can you try this configuration ?

# config/twig_component.yaml
twig_component:
  anonymous_template_directory: 'Bar/'
  defaults:
    'Bar\': 'Bar/'

Works for me locally in 2.20