inessential by Brent Simmons

KVO, My Enemy

One of the keys to the stability of the shipping versions of NetNewsWire is that we don’t allow KVO (Key-Value Observing).

KVO is a false convenience — it’s often easier than setting up a delegate or old-fashioned notification. But to use KVO is to just ask for your app to crash.

And not just crash, but crash in hard-to-figure-out ways.

* * *

So we don’t let KVO into the app — except, well, we’re using Operation and OperationQueue for Feedly syncing, and the thing about Operation is that it uses KVO to signal when it’s finished. There’s no way of getting around that if you want to use Operation.

Okay. Fine. It’s worth it, right? It’s just this one small use of KVO. Surely we’ll be fine.


KVO is why I drink.