Illuminate\Translation\Translator::localeArray may return duplicate locales

[YuriWPY]

Laravel Version

12.44.0

PHP Version

8.4.11

Database Driver & Version

No response

Description

When $this->locale and $this->fallback are same values (e.g. en), the following method returns an array with duplicates:

    /**
     * Get the array of locales to be checked.
     *
     * @param  string|null  $locale
     * @return array
     */
    protected function localeArray($locale)
    {
        $locales = array_filter([$locale ?: $this->locale, $this->fallback]);

        return call_user_func($this->determineLocalesUsing ?: fn () => $locales, $locales);
    }

These duplicates are used later in the Translator::get() method where a loop tries to find a translation:

$locales = $fallback ? $this->localeArray($locale) : [$locale];

foreach ($locales as $languageLineLocale) {
	if (! is_null($line = $this->getLine(
		$namespace, $group, $languageLineLocale, $item, $replace
	))) {
		return $line;
	}
}

When a translation can't be found from the first attempt, it creates a condition when $this->getLine(...) is called twice for no good reason.

In my opinion, either Translator::localeArray method should return only unique values, or Translator::get method should ignore duplicate locales.

Steps To Reproduce

The following call can be used to set a fallback locale:
\Illuminate\Support\Facades\Lang::setFallback('en')

The bug can be reproduced by calling a Translator::get() method where $locale parameter matches the fallback and where the $key parameter does not exist in the translation file:

\Illuminate\Support\Facades\Lang::get(key: 'abcd', locale: 'en')