ZF-11976: Zend_Cache_Core::setBackend should accept Zend_Cache_Backend_Interface

Description

Hello ZF team. First of all thank you for your work. There is strange behavior with one of the cache function (Zend_Cache_Core::setBackend). It uses Zend_Cache_Backend as parameter, but more logical if it use Zend_Cache_Backend_Interface instead.

Comments

Downgrading to Minor, as all backends extend Zend_Cache_Backend at this point. There really isn't any gain that I can see in changing this now, and there is the possibility that people out there may have created custom backends that extend Zend_Cache_Backend but don't implement the interface and so those would no longer be accepted by Zend_Cache_Core. It may be worth making a note in the manual about needing to extend Zend_Cache_Backend if you're creating a new custom backend, though