Prevent TypeError in validateDigits when attribute value is an array

[elyass-dehghan]

This pull request fixes an issue where the validateDigits method throws a TypeError when the validated attribute value is an array instead of a string.

Previously:

preg_match('/^\d{'.$parameters[0].'}$/', $value);

would throw:

preg_match(): Argument #2 ($subject) must be of type string, array given

Now, the method ensures that the value is a string before running the validation, preventing framework-level exceptions and keeping behavior consistent with other validation rules.

Example case:

$request->validate([
    'code' => 'digits:4',
]);

If the request accidentally sends code[], Laravel will now gracefully handle the invalid type instead of throwing an error.

Impact:
This change improves robustness of the validation system by preventing a framework exception and instead treating the case as a simple validation failure.

[macropay-solutions]

Just as a note this can be prevented

$request->validate([
    'code' => 'numeric|digits:4',
]);