What causes "Enum "%s" does not exist." in twigphp/Twig?

Pass the correct fully-qualified enum class name (e.g. 'App\Enum\Status'), verifying it with var_dump(enum_exists('App\Enum\Status'))

twigphp/Twig · error · RuntimeError

Enum " " does not exist.

Error message

Enum "%s" does not exist.

What it means

Thrown by CoreExtension::enumCases, which backs Twig's `enum_cases` function. It validates its argument with enum_exists() and throws this RuntimeError when the given class string is not an existing enum — either the class does not exist at all or it exists but is a regular class/interface, not an enum.

Solutions

Pass the correct fully-qualified enum class name (e.g. 'App\Enum\Status'), verifying it with var_dump(enum_exists('App\Enum\Status'))
Run composer dump-autoload if the class exists but is not autoloaded
Check the argument is a string, not a variable holding an instance — for instances, pass the FQCN or use `enum_cases(class-string)`
Require PHP >= 8.1 and make the referenced type actually a backed/unit enum

Example fix

// before (Twig)
{% for case in enum_cases('Status') %}...{% endfor %}
// after
{% for case in enum_cases('App\\Enum\\Status') %}...{% endfor %}

Defensive patterns

Strategy: type-guard

Validate before calling

if (!\is_string($enum) || !\enum_exists($enum)) {
    throw new \InvalidArgumentException("Not a valid enum class: " . print_r($enum, true));
}

Type guard

function isValidEnumClass(mixed $class): bool {
    return \is_string($class) && \enum_exists($class);
}

Try / catch

try {
    $cases = $twig->render('t.html', ['enumClass' => $enumClass]);
} catch (\Twig\Error\RuntimeError $e) {
    if (str_contains($e->getMessage(), 'does not exist')) {
        // fall back to a hardcoded case list or log misconfiguration
    } else { throw $e; }
}

Prevention

Always pass fully-qualified class-name strings ('App\Enum\Status') into enum_cases
Run composer dump-autoload after adding/moving enums
Pin PHP >= 8.1 where enums exist and add a static analysis rule banning non-enum class strings
Keep enum FQCNs in PHP constants shared between templates and code instead of inline strings

When it happens

Trigger: Calling `enum_cases('App\Status')` in a template where the FQCN is wrong (missing namespace, typo, leading backslash handling), the enum class has not been autoloaded, or a non-enum class is passed. Also when passing a non-string (e.g. an object) that stringifies incorrectly.

Common situations: Refactoring/moving an enum without updating the template string; using a short class name without namespace; autoloading misconfiguration (composer dump-autoload not run); passing a class that is an enum in newer PHP but a class in older versions of your codebase; PHP < 8.1 environments where enums do not exist.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of twigphp/Twig@a414c3a491 (2026-09-13). Data as JSON: /api/errors/c2407570a4f70a92. Report an issue: GitHub.

Appendix: source

Thrown at src/Extension/CoreExtension.php:1633

            return '';
        }
    }

    /**
     * Returns the list of cases of the enum.
     *
     * @template T of \UnitEnum
     *
     * @param class-string<T> $enum
     *
     * @return list<T>
     *
     * @internal
     */
    public static function enumCases(string $enum): array
    {
        if (!enum_exists($enum)) {
            throw new RuntimeError(\sprintf('Enum "%s" does not exist.', $enum));
        }

        return $enum::cases();
    }

    /**
     * Provides the ability to access enums by their class names.
     *
     * @template T of \UnitEnum
     *
     * @param class-string<T> $enum
     *
     * @return T
     *
     * @internal
     */
    public static function enum(string $enum): \UnitEnum
    {

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