Form Type Extension

Hey Adam!

Ah, great catch! Thank you for reporting it! It was fixed in: https://github.com/knpunive... , so now people may copy code from the Tip :)

Cheers!

Yo Lijana Z.!

Excellent question. The answer is.... it depends on what you are trying to do ;). Let's look at the error:

The option "x" does not exist

There are 3 different situations where you might get this error:

A) You might get this error if you simply have a "typo" on an option name - e.g. you use requured instead of required. In that case, you definitely don't want to create a form type extension - you just want to fix your typo. That's something I like a lot about the "options" system: you can't typo something and have it "silently" fail: you will get a clear error that the option does not exist.

B) You might get this error in a situation where you are trying to pass a custom option to a "form type" class that you created. For example, suppose you have a "RegistrationFormType" that you use in 2 different pages on your site. On one page, you DO want a "subscribe to newsletter" checkbox but on another screen (for some reason) you want the same form but without that checkbox. One way to do that is to "invent" a new option that you pass when creating your RegistrationFormType in the controller - e.g. 'with_newsletter' => true. In this case, you are "inventing" an option. But you do not need a form type extension if you just want to add an option to one form type (and also if that form type is your class). Instead, you create the option by adding it to the configureOptions section of your RegistrationFormType.

C) You might get this error in a situation where you are trying to pass a custom option to a "field" that you did not create - e.g. TextareaType. OR because you want to be able to pass an option to any (or at least many) different fields. This is where you need a form type extension: because you want to add a custom option to a form field that you did not create (something in vendor/) or because you want to add a custom option to many/all form fields in your system.

Creating a form type extension is really a pretty rare thing to need to do - it's very powerful, but it's not that common that you need to add a custom option to a vendor "type" or to "all" types. The options system in general can be a confusing, so let me know if this helps... or just make things more confusing ;).

Cheers!

Thanks, it helps. I hope those videos and comments will not be gone while symfony will be used just in case I need to read/watch again :)

Hey @stephansav!

Hmm. My guess is that you may have an indentation problem in your services.yaml file. Any extra (or missing) indentation will have a different "meaning" when it's parsed - so look very closely at your indentation levels and compare them with mine :). For example, I think you might have a - that is maybe only indented 2 or 4 spaces from the root of the file (so 2 or 4 spaces in total) and this is looking like an array with a "0" index under "services" to Symfony.

Let me know if that helps!

Cheers!

Hi,

I checked what you told me and there is no problem with the indentation in services.yaml. Here my code:

App\Form\TypeExtension\TextareaSizeExtension:
    tags:
        - { name: form.type_extension,
            extended_type: Symfony\Component\Form\Extension\Core\Type\TextareaType }

How can I solve that?

Hey @stephansav!

Ah, thanks for posting this! I mis-read the error completely! I think you might be missing a "use" statement for the TextareaType inside your TextareaSizeExtension. Let me know if that's it :).

Cheers!

Hi,
that's it. Thank you very much! :)

Hey Christoph

That's odd, it should have detected your extension, the name of the file (IIRC) doesn't do anything. Symfony calls the getExtendedTypes method in order to detect on which field types the extension should be applied. I think you just had to clear your cache. If you rename the extension to its original name, does the problem re-appears?

Cheers!

Hey @Aaron!

Hmm, I think our description of this might be inaccurate indeed. Because, in this video, we're implementing the interface directly, I believe you will need both methods until Symfony 5. However, the getExtendedType should not actually be called anymore - you need to have it to make the interface happy, but it can be blank. If you implement the public static function getExtendedTypes() method, then you should not need the config.

So, have both methods, leave getExtendedType blank, and add the new "s" version (as static). Then you should not need the config.

Sorry about the confusion!

Cheers!

There is a type inside the code block of this page: As you said, getExtendedTypes() as to be declared as a public static function. On SymfonyCast it is declared just as public function. "static" is missing on the code block

Hey Mike,

Thank you for reporting it! getExtendedTypes() really should be declared as "public *static* function". We'll fix it soon in the tutorial.

Cheers!

Hey Stephane

Thanks for highlighting this new change. Have you tried to implement getExtendedTypes method (notice an ending S on the method name) and then remove the configuration? I believe it should work

Cheers!

Hey Diego,

This solution does not work on Symfony 4.2.1, it only works when we code as if we are using Symfony 4.1 in a Symfony 4.2.1 environment. Is there a reason for this?

////UPDATE --> 15Min Later...\\\

The caveat here is that the static function "getExtendedTypes" (yes I noticed the 'S' at the end) should be returning an Array.

SO for everyone who is running into trouble with this part here is the complete code:

vars['attr']['rows'] = 3;
}

public function finishView(FormView $view, FormInterface $form, array $options)
{
}

public function configureOptions(OptionsResolver $resolver)
{
}

public function getExtendedType()
{
}

public static function getExtendedTypes()
{
return [TextareaType::class];
}

}

Oh, yes, you are totally right. I forgot to mention that it must return an array (or been more precise, an iterable) now

Cheers!