Question

I can’t undarstand why my code is crashes:

<__NSCFSet: 0x74957b0> was mutated while being enumerated

Previously I read simular topics but their problem was that the code calls in different threads. My code always calls in Thread 1.

It crashes times to time.

Here is a code where it happens:

- (void)processReceivedResponse:(JTResponse *)aResponse {

    NSParameterAssert(aResponse);

    id <JTRequestDelegate> delegate = [self processResponseWithReceiver:aResponse];

    if (delegate == nil) {

        for (JTObserver *someObserver in observers) {

            if (someObserver.requestType == aResponse.type && 
                     ![someObserver.delegate isEqual:delegate]) {

                [someObserver.delegate didReceiveResponse:aResponse];
            }
        }
    }
}

Answer 1

The error you’re getting is caused by something changing the “observers” set while you’re looping through it.

It’s hard to tell what that might be from just the snippet you posted. Is something in the delegate you’re invoking on someObserver changing the “observers” set?