Because everyone loves Java.

It's not simply a case of "null is bad", it allows other optional features such as TTL control, adding tags and all sorts of fun.

https://groups.google.com/forum/#!msg/php-fig/_HMACz6NzrU/au9k2Vkro2gJ

I am responding with links to the mailing list conversations that have already covered this, hoping to either end this PR discussion or move it to the ML. 

Anybody in the FIG will tell you that these discussions need to happen on the mailing list, so PLEASE go over there and discuss it. Find a topic that is relevant and reply, or make your own called "[Cache] Some specific question/feature".

I can almost guarantee you anything you have to say has been discussed before, but post away and we'll try and link to relevant conversations or reply in kind if the new point is new. :)