facebook/facebook-ios-sdk — pull request #458 by nevyn (2012-05-16 12:36:47+00:00)
Title: Clear delegate when invalidating request (FIXES COMMON CRASH)

If the request is outstanding, it will callback to FBFrictionlessRequestSettings even
after it has been deallocated. If you have a short-lived Facebook instance in your app
(e g for just enabling SSO), this means you crash maybe every fifth SSO.