Another option would be to filter out options that should not be available (see #32657).

I didn't know these related issues but the idea is the same I guess: we need more control on "forced" choices.

I'm sure my comment is naïve, but here it is: in my head, all these prepopulated choice types (language, country, locale, etc.) should define an internal allChoices option and a public/external choices option.

If choices is empty, then we do choices = allChoices ... but if I define choices, then we filter allChoices to pick only those values. Don't know if this is possible or makes sense ... but to me, as a user, I'd love to just define choices to filter the values of these types.

I like @javiereguiluz idea.

Closing this one then, and let's try to implement Javier idea.

I don't think we need another option in choice subtypes for this, if one wants to define the choices option one should use the ChoiceType instead. I agree that we should leverage a choice_filter option for more specific use cases (like type extension for core types) as suggest by @xabbuh. I've got a branch for it based on my other open PRs, just waiting to be pushed once they are dealt with.

@HeahDude I don't understand how these things work internally, but this is what we want to provide to end users. Do we agree on it?

// display all languages (translated into the user language)
$builder->add('language', LanguageType::class);

// display only these languages (translated into the user language)
$builder->add('language', LanguageType::class, [
    'choices' => ['es', 'fr', 'en'],
]);


// display all countries (translated into the user language)
$builder->add('country', CountryType::class);

// display only these countries (translated into the user language)
$builder->add('country', CountryType::class, [
    'choices' => ['JP', 'US'],
]);

// etc.

We agree on the need not on the implementation yet.
The choice_filter would allow (for every choice type) something like:

// display only these languages (translated into the user language)
$builder->add('language', LanguageType::class, [
    'choice_filter' => fn($choice) => in_array($choice, ['es', 'fr', 'en'], true),
]);

But once we have this feature we could indeed use the choices options of intl choice types as a short hand for DX.

i generally like @javiereguiluz's proposal, but semantically i expect choices to hold values and labels.

In this case, adding a new choice_filter option is the same approach. Either ChoiceType generic or specific for Intl types.

back to #32657 :)