symfony/translation · error · UnsupportedSchemeException

The scheme "null" is not supported by this provider.

Error message

The scheme "null" is not supported by this provider.

What it means

Thrown by NullProviderFactory::create() when a Dsn whose scheme is not 'null' is passed to the factory. The factory only supports the 'null' scheme (used to disable translation providers); any other scheme is unsupported and surfaces as UnsupportedSchemeException.

Solutions

1. Ensure the DSN scheme matches the factory: use scheme 'null' for NullProviderFactory
2. Use the correct provider factory for the scheme (loco, locomotive, acfred, crowdin, etc.)
3. If you intend no provider, set the DSN to 'null://default'

Example fix

// before
$factory->create(new Dsn('loco://KEY@default'));
// after
$factory->create(new Dsn('null://default')); // or use LocoProviderFactory

if ($dsn->getScheme() !== 'null') {
    throw new \LogicException('NullProviderFactory only handles the null scheme.');
}

$scheme = $dsn->getScheme();
if ($scheme !== 'null') { /* route to correct factory */ }

try {
    $provider = $factory->create($dsn);
} catch (UnsupportedSchemeException $e) {
    // fall back to the factory whose supported schemes contain $dsn->getScheme()
}

When it happens

Trigger: Calling create($dsn) on a NullProviderFactory (or a provider factory whose getSupportedSchemes() is ['null']) with a Dsn whose getScheme() is not 'null'.

Common situations: Routing a DSN like 'loco://key@default' to the wrong factory, misconfigured provider factory services, or custom factories delegating to NullProviderFactory.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Provider " " not found. Available: " ".
• The scheme is not supported by any provider.
• The " ()" method cannot be called as the wrapped translator…
• No loader is registered for the
• No loader is registered for the

AI-assisted analysis of symfony/translation@ae9e8a51bc (2026-09-15). Data as JSON: /api/errors/2785c2e7809c5333. Report an issue: GitHub.

Appendix: source

Thrown at Provider/NullProviderFactory.php:27

 * file that was distributed with this source code.
 */

namespace Symfony\Component\Translation\Provider;

use Symfony\Component\Translation\Exception\UnsupportedSchemeException;

/**
 * @author Mathieu Santostefano <msantostefano@protonmail.com>
 */
final class NullProviderFactory extends AbstractProviderFactory
{
    public function create(Dsn $dsn): ProviderInterface
    {
        if ('null' === $dsn->getScheme()) {
            return new NullProvider();
        }

        throw new UnsupportedSchemeException($dsn, 'null', $this->getSupportedSchemes());
    }

    protected function getSupportedSchemes(): array
    {
        return ['null'];
    }
}

View on GitHub (pinned to ae9e8a51bc)