After the League's Container package has been reintroduced, all the
code that implements the dependency injection mechanism in woocommerce
can be brought back as well.
Since reverting the PR at this point would be a mess I've gone ahead and removed the internals of the container. We should aim to keep the class since it's now part of our public API but it won't work as expected anymore. This is fine for now since we don't actually have anything in it!
1. Since our code style dictates that these be `final` methods, we shouldn't be concerned about overlap.
2. There is precedent for `init` methods as requirements before using class instances.
Since we need to maintain backwards compatibility for class constructors we should settle on using method injection instead of constructor injection. I've replaced the `Definition` class we're using with one that doesn't support constructor arguments and added a check for auto_arg addition. Note that we don't check for method existence in the extended container. This is because reflection is unnecessarily expensive and we should avoid it if at all possible.
The following methods are added and can be invoked using `WC()`,
they just redirect to the same methods in LegacyProxy:
call_function
call_static
get_instance_of
- Method and class renames.
- Removed unnecessary autoloader registration.
- Add a unit test for classes with non-object type hints
in constructor arguments.
- `get_instance_of` accepts now arguments to be passed to the
class constructor if necessary.
- `get_special_instance_of` method removed, instead, now if a method
named `get_instance_of_<lowercased class name>` exists in the class,
it is used to get the instance of the class.
- A couple more unit tests added.