[1.x] Implement Support for Translatable Validation Attribute Errors

[DavideIadeluca]

Fixes #0000

Note

This PR aims to implement the translation of attributes of validation errors, a feature initially started nearly a decade ago (see this commit) but seemingly never completed.

Changes proposed in this pull request:

• Implement support for translating attributes of backend validation errors.
• Add English translations for new attributes
• Move tag validation attribute translations from core to tags per discussion in Move locale files from language pack to core #2408 (comment)

Reviewers should focus on:

• First and foremost, evaluate if this change is not a breaking change and can safely be done on 1.x. The only concern with my implementation is that some extensions may have already defined a key in the validation namespace, like validation.attributes.name, which could lead to unexpected behavior. In any case, I recommend reading the discussion in Move locale files from language pack to core #2408 (comment) to get more context on this.

• Would there be a way how the same could be achieved without having to explicitly return a translation key for each attribute? Let's say there was some kind of generic solution, how would we handle cases such as this:

  framework/extensions/package-manager/src/ConfigureComposerValidator.php

  Lines 18 to 24 in 5bd7e5d

  	protected $rules = [
  	'minimum-stability' => ['sometimes', 'in:stable,RC,beta,alpha,dev'],
  	'repositories' => ['sometimes', 'array'],
  	'repositories.*' => ['sometimes', 'array', 'required_array_keys:type,url'],
  	'repositories.*.type' => ['in:composer,vcs,path'],
  	'repositories.*.url' => ['string', 'filled'],
  	];

• The only validation logic I knowingly didn't change is the SettingsValidator, as in that case it would certainly not be maintainable to add support for every possible case:

  framework/framework/core/src/Settings/SettingsValidator.php

  Lines 24 to 53 in 5bd7e5d

  	protected $globalRules = [
  	'max:65000',
  	];
  	/**
  	* Make a new validator instance for this model.
  	*
  	* @param array $attributes
  	* @return \Illuminate\Validation\Validator
  	*/
  	protected function makeValidator(array $attributes)
  	{
  	// Apply global rules first.
  	$rules = array_map(function () {
  	return $this->globalRules;
  	}, $attributes);
  	// Apply attribute specific rules.
  	foreach ($rules as $key => $value) {
  	$rules[$key] = array_merge($rules[$key], $this->rules[$key] ?? []);
  	}
  	$validator = $this->validator->make($attributes, $rules, $this->getMessages());
  	foreach ($this->configuration as $callable) {
  	$callable($this, $validator);
  	}
  	return $validator;
  	}

• Should a similar solution be PR'd for 2.x or are you looking for something more lean perhaps without the risk of a breaking change?

Screenshot

QA

1. Install a language pack such as flarum-lang/german or flarum-lang/dutch
2. Switch the Forum UI to another language (not english)
3. Try to submit a new discussions with no title or content. You should now see the translated version of title or content

Necessity

• Has the problem that is being solved here been clearly explained?
• If applicable, have various options for solving this problem been considered?
• For core PRs, does this need to be in core, or could it be in an extension?
• Are we willing to maintain this for years / potentially forever?

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).
• Core developer confirmed locally this works as intended.
• Tests have been added, or are not appropriate here.

Required changes:

• Related documentation PR: (Remove if irrelevant)
• Related core extension PRs: (Remove if irrelevant)

[SychO9]

It should be possible to edit AbstractValidator and manipulate the messages to dynamically check for the existence of a validation attribute translation. Mainly, the result of getMessages.

[SychO9]

The only concern is potential conflicts in attribute names between extensions. So might be better to put extension validation under the extension namespace.

[imorland]

As @SychO9 suggests, we run the possibility of conflicts here if extensions register the same attribute names, but want a different translation.

Let's scope everything under the extension name(s) please

[DavideIadeluca]

@imorland I moved the validation translations to the extension namespaces

It should be possible to edit AbstractValidator and manipulate the messages to dynamically check for the existence of a validation attribute translation. Mainly, the result of getMessages.

@SychO9 Can you make an example of what you were thinking? Now that some validation strings are in the extension namespaces, I feel like it would get messy if the AbstractValidator has to support both the structure of core and extensions but maybe I'm missing something here

[SychO9]

here is a proof of concept of how you can obtain the extension ID related to the validator:

// this would be nice in a trait, used by the abstract validator in this case
protected function getClassExtensionId(): ?string
{
    $extensions = resolve(ExtensionManager::class);

    return $extensions->getExtensions()
                ->mapWithKeys(function (\Flarum\Extension\Extension $extension) {
                    return [$extension->getId() => $extension->getNamespace()];
                })
                ->where(function ($namespace) use ($class) {
                    return $namespace && str_starts_with(static::class, $namespace);
                })
                ->keys()
                ->first();
}

you would have to add this to Extension.php

    public function getNamespace(): ?string
    {
        return Collection::make($this->composerJsonAttribute('autoload.psr-4'))
            ->filter(function ($source) {
                return $source === 'src/';
            })
            ->keys()
            ->first();
    }

once you have that, you could theoretically use it in the getMessages method to automatically point to $extId.validation.attributes.$attribute or validation.attributes.$attribute if core (extId null)

also imo it's not necessary to replace . with _ for attribute locale key.