silverstripe/sapphire — pull request #734 by hafriedlander (2012-08-22 21:29:48+00:00)
Title: API Reverse config extra statics control flow

Config system used to provide an add_static_source method, which was intended for
use by Extensions to add statics. But extensions for a class arent initialised
until at least one instance of that class is created, so before that the
Config system didnt include values from extensions

This patch reverses the control flow, so that the Config system explictly asks
each Object for its additional config sources via the new method
get_extra_config_sources. This method returns an array that can contain
string names of classes and also raw associative arrays.

The developer visible change is that Extension#add_to_class has been
deprecated. Instead there is a new method, get_extra_config, which has
the same method signature but needs to guarantee that it doesnt
cause side effects. Additionally there is no need to call
parent::get_extra_config - this is handled automatically.