Problems with Dynamic Class Instantiation and Type Hinting in PHP 8.1
I've encountered a strange issue with After trying multiple solutions online, I still can't figure this out... I'm working with a peculiar scenario when trying to dynamically instantiate classes in PHP 8.1 using type hinting. I have an interface `UserServiceInterface` and two implementations: `AdminUserService` and `RegularUserService`. I'm attempting to instantiate these classes based on a string value from a configuration file. The scenario arises when I try to type hint the method parameters while using a variable to define the class name. Here’s what I have: ```php interface UserServiceInterface { public function getUserData(); } class AdminUserService implements UserServiceInterface { public function getUserData() { return 'Admin Data'; } } class RegularUserService implements UserServiceInterface { public function getUserData() { return 'Regular Data'; } } function getService(string $userType): UserServiceInterface { switch ($userType) { case 'admin': return new AdminUserService(); case 'regular': return new RegularUserService(); default: throw new InvalidArgumentException('Invalid user type'); } } // Fetching user type from a config $userType = 'admin'; // This could be dynamic $userService = getService($userType); echo $userService->getUserData(); ``` While this code runs perfectly when I pass 'admin' or 'regular', I started experiencing an unexpected behavior where passing an unrecognized user type (like 'superadmin') does not throw an exception until I call a method on `UserServiceInterface`. I get a `PHP Warning: Uncaught behavior: Call to a member function getUserData() on null` behavior which is quite confusing. I initially thought the scenario was related to the type hinting or the variable class instantiation, but it seems more like a delayed exception handling scenario. I've tried adding type checking before the method call, but that just seems like a workaround. How can I ensure that I properly handle the invalid user types right at the instantiation phase? Is there a best practice for such scenarios in PHP 8.1? Any insights would be greatly appreciated! I'm coming from a different tech stack and learning Php.