symfony/translation · error · LogicException

The " ()" method cannot be called as the wrapped translator…

Error message

The "%s()" method cannot be called as the wrapped translator class "%s" does not implement the "%s".

What it means

Thrown by PseudoLocalizationTranslator::getCatalogue() as a LogicException when the decorated translator does not implement TranslatorBagInterface. PseudoLocalizationTranslator is a decorator that only supports locale translation; catalogue access requires the wrapped object to expose the catalogue bag API.

Solutions

Ensure the wrapped translator implements TranslatorBagInterface (use Symfony\Component\Translation\Translator)
Access the catalogue from the underlying bag service instead of the decorator
If you only need pseudo-localized messages, use trans()/getLocale() instead of catalogue methods

Example fix

// before
$pseudo = new PseudoLocalizationTranslator($someTranslatorWithoutBag);
$pseudo->getCatalogue();
// after
$pseudo = new PseudoLocalizationTranslator(new \Symfony\Component\Translation\Translator('en'));
$pseudo->getCatalogue();

Defensive patterns

Strategy: type-guard

Validate before calling

if (!$inner instanceof TranslatorBagInterface) {
    throw new \LogicException('Wrapped translator must implement TranslatorBagInterface to access catalogues.');
}

Type guard

$bag = $inner instanceof TranslatorBagInterface ? $inner : null;

Try / catch

try {
    $catalogue = $pseudo->getCatalogue($locale);
} catch (LogicException $e) {
    $catalogue = $this->translatorBag->getCatalogue($locale);
}

Prevention

Always wrap Symfony\Component\Translation\Translator (it implements the bag interface)
Do not use pseudo-localization decorators around minimal test doubles in production code
Read the decorator's docblock: catalogue methods require TranslatorBagInterface

When it happens

Trigger: Calling getCatalogue() on a PseudoLocalizationTranslator whose wrapped translator class lacks TranslatorBagInterface.

Common situations: Wrapping a custom or partial translator implementation instead of Symfony's Translator, or decorating only TranslatorInterface in a service alias.

Understand the failure class

Background: "is not a compatible type" / "cannot merge" errors: when a value's type doesn't match what the library requires — this error's family across 65 libraries.

Related errors

AI-assisted analysis of symfony/translation@ae9e8a51bc (2026-09-15). Data as JSON: /api/errors/6bd391bfdd28039a. Report an issue: GitHub.

Appendix: source

Thrown at PseudoLocalizationTranslator.php:122

            $this->addAccents($trans, $text);
        }

        $this->expand($trans, $visibleText);

        $this->addBrackets($trans);

        return $trans;
    }

    public function getLocale(): string
    {
        return $this->translator->getLocale();
    }

    public function getCatalogue(?string $locale = null): MessageCatalogueInterface
    {
        if (!$this->translator instanceof TranslatorBagInterface) {
            throw new LogicException(\sprintf('The "%s()" method cannot be called as the wrapped translator class "%s" does not implement the "%s".', __METHOD__, $this->translator::class, TranslatorBagInterface::class));
        }

        return $this->translator->getCatalogue($locale);
    }

    public function getCatalogues(): array
    {
        if (!$this->translator instanceof TranslatorBagInterface) {
            throw new LogicException(\sprintf('The "%s()" method cannot be called as the wrapped translator class "%s" does not implement the "%s".', __METHOD__, $this->translator::class, TranslatorBagInterface::class));
        }

        return $this->translator->getCatalogues();
    }

    private function getParts(string $originalTrans): array
    {
        if (!$this->parseHTML) {
            return [[true, true, $originalTrans]];

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