AFNetworking/AFNetworking — comment on commit 9a91afe3e25e252b3145815799dbbe7dde3d8008
File: AFNetworking/AFHTTPClient.m line 480
By warrenm:

The second part of this conditional is true if there is a valid pointer-to-NSError* passed in, not if the previous synchronous request failed to produce an error. For that, we probably need (response && (!error || !*error)), or equivalently by de Morgan's: (response && !(error && *error)).