Re: On BC and interfaces

> Basically we shouldn't break any interfaces that are user-facing but > we are free to change things internally as much as we want as long as the > external interface is honored. So how do you actually go about adding a feature that requires an interface change? Take for example the SessionHandler class, that implements SessionHandlerInterface. Now lets say you want to add functionality to the class that allows a user to override create_sid, and provide user-generated session ids. It doesn't make sense to add it to the class and not the interface, so what do you do? * Add to SessionHandlerInterface and break BC? * Create SessionHandlerInterfaceEx that extends the original, and have the the class implement that? * Create SessionHandlerInterfaceEx that contains only the new method, and have the class implement both interfaces? * Add to the class, but do not touch the interface?