Plugin System with Tags

Hi! I'm using Symfony 5.2.
I have a notice about "The Easy Way" (<argument type="tagged" tag="knpu_ipsum_word_provider" />). I had the following configuration in KnpULoremIpsumExtension::load():

...
if (null !== $config['word_provider']) {
    $container->setAlias('knpu_lorem_ipsum.word_provider', $config['word_provider']);
}

And the following configuration in "services.xml":

        ...
        <service id="knpu_lorem_ipsum.knpu_ipsum" class="KnpU\LoremIpsumBundle\KnpUIpsum" public="true">
            <argument type="tagged_iterator" tag="knpu_ipsum_word_provider" /> <!-- filled in via a compiler pass -->
            <argument /> <!-- unicorns_are_real -->
            <argument /> <!-- min_sunshine -->
        </service>
        <service id="KnpU\LoremIpsumBundle\KnpUIpsum" alias="knpu_lorem_ipsum.knpu_ipsum" public="false" />
        
        <service id="knpu_lorem_ipsum.knpu_word_provider" class="KnpU\LoremIpsumBundle\KnpUWordProvider">
            <tag name="knpu_ipsum_word_provider" />
        </service>
        <service id="knpu_lorem_ipsum.word_provider" alias="knpu_lorem_ipsum.knpu_word_provider" public="false" />

Words from CustomWordProvider weren't present on page. So, I still should or add tag definition for provider in "services.yaml" in my main app:

App\Service\CustomWordProvider:
        tags: ['knpu_ipsum_word_provider']

... either set tag in KnpULoremIpsumExtension::load():

$container
        ->registerForAutoconfiguration(WordProviderInterface::class)
        ->addTag('knpu_ipsum_word_provider')
;

Maybe, I've done something wrong, but only explicit tag definition for App\Service\CustomWordProvider worked for me (<i>in case of "easy way"</i>).

Hey @Boolean_Type!

Hmm, let's see. So first, as you know, one way or another we must to add the knpu_ipsum_word_provider tag to the CustomWordProvider service. But, there are two ways to do this... and you listed both of them :). Either you can add the tag directly, or you can register the interface it implements for autoconfiguration. How you add the tag doesn't matter - it will work the same both ways. We actually do the registerForAutoconfiguration() thing - we do it in the next chapter: https://symfonycasts.com/screencast/symfony-bundle/tags-compiler-pass#codeblock-1ed6575410

Cheers!

Hi!
Am I correct saying that autoconfiguring tags does not work for bundle services since there's a comment in code snippet at the given link like

# this config only applies to the services created by this file

? In my application I have an interface with auto-configured tag in services.yaml. And my bundle service implementing that interface does not have a tag on it until I explicitly add the tag to bundle's services.xml.

Hey erop!

That's 100% correct! The reason is that the instanceof stuff (just like the defaults) stuff applies to only the current file that this code appears in. This was done on purpose: it's a powerful way to make your life easier, but if it affected your entire application, crazy things would happen :). You could add an instanceof in a bundle that you're creating. But typically, as a best practice, bundle should explicitly require everything: the "shortcuts" are meant to help application developers more than developers of re-usable code.

Cheers!

Thank you, Ryan!

Is it possible that now this argument is not an array but an object of type RewindableGenerator?
<argument type="tagged" tag="knpu_ipsum_word_provider"/>

That's what I get when I dump $wordProviders in the constructor of class KnpUIpsum. :-/

It does work when you remove the typehint "array $wordProviders"

Hey Laurens M.!

Hmm. I can't find a change in Symfony that would specifically cause this. However, from checking the code, it looks like this has always been the case - even the original blog post about this feature shows using the iterable type-hint, not array: https://symfony.com/blog/new-in-symfony-3-4-simpler-injection-of-tagged-services

So, we'll add a note about that! When I created this, I was thinking that you could simply use the tagged argument type and make no other changes to your code. But, it looks like the array type-hint does need to change to iterable.

Thanks for bringing this up!

Thanks Ryan, iterable as typehint indeed works like a charm. I appreciate the quick and clear response, all the bests!