StoreKit SKProductsRequest Crash

Question

I use the following code to request a list of products as per the In-App Purchase Programming Guide. It used to work fine in my iPhone application, however now it crashes every time the product list is requested. The delegate method (void)productsRequest:(SKProductsRequest **)request didReceiveResponse:(SKProductsResponse **)response is never called.

SKProductsRequest *request = [[SKProductsRequest alloc] initWithProductIdentifiers:[NSSet setWithObject:@"my.product.identifier"]];
[request setDelegate:self];
[request start];

As I said, it worked perfectly fine, then just stopped working. This is the crash which occurs when the above code is called.

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x00000011
Crashed Thread:  0

Thread 0 Crashed:
0   libobjc.A.dylib                 0x000034f8 objc_msgSend + 24
1   StoreKit                        0x00003e18 -[SKProductsRequest handleFinishResponse:returningError:] + 40
2   StoreKit                        0x000050c4 -[SKRequest _requestFinishedNotification:] + 152
3   Foundation                      0x00019b9a _nsnote_callback + 150
4   CoreFoundation                  0x0006c2de __CFXNotificationPost_old + 390
5   CoreFoundation                  0x0001ab32 _CFXNotificationPostNotification + 122
6   Foundation                      0x000048e4 -[NSNotificationCenter postNotificationName:object:userInfo:] + 64
7   AppSupport                      0x0000bb42 -[CPDistributedNotificationCenter deliverNotification:userInfo:] + 38
8   AppSupport                      0x0000cf66 _CPDNDeliverNotification + 198
9   AppSupport                      0x0000ba4a _XDeliverNotification + 110
10  AppSupport                      0x00002e82 migHelperRecievePortCallout + 122
11  CoreFoundation                  0x000742ac __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 22
12  CoreFoundation                  0x000761d6 __CFRunLoopDoSource1 + 158
13  CoreFoundation                  0x0007718e __CFRunLoopRun + 574
14  CoreFoundation                  0x0001e0bc CFRunLoopRunSpecific + 220
15  CoreFoundation                  0x0001dfca CFRunLoopRunInMode + 54
16  GraphicsServices                0x00003f88 GSEventRunModal + 188
17  UIKit                           0x00007b40 -[UIApplication _run] + 564
18  UIKit                           0x00005fb8 UIApplicationMain + 964
19  myapp                           0x00002fae main (main.m:13)
20  myapp                           0x00002f58 start + 32

Thread 1:
0   libSystem.B.dylib               0x00034e84 kevent + 24
1   libSystem.B.dylib               0x00102a48 _dispatch_mgr_invoke + 88
2   libSystem.B.dylib               0x00102494 _dispatch_queue_invoke + 96
3   libSystem.B.dylib               0x00102634 _dispatch_worker_thread2 + 120
4   libSystem.B.dylib               0x0008b53c _pthread_wqthread + 392
5   libSystem.B.dylib               0x00082b6c start_wqthread + 0

Thread 2:
0   libSystem.B.dylib               0x00000ab0 mach_msg_trap + 20
1   libSystem.B.dylib               0x00002f94 mach_msg + 60
2   CoreFoundation                  0x00074b18 __CFRunLoopServiceMachPort + 88
3   CoreFoundation                  0x000770e0 __CFRunLoopRun + 400
4   CoreFoundation                  0x0001e0bc CFRunLoopRunSpecific + 220
5   CoreFoundation                  0x0001dfca CFRunLoopRunInMode + 54
6   WebCore                         0x0000370c RunWebThread(void*) + 552
7   libSystem.B.dylib               0x0008af80 _pthread_start + 364
8   libSystem.B.dylib               0x0007d014 thread_start + 0

Thread 3:
0   libSystem.B.dylib               0x00000ab0 mach_msg_trap + 20
1   libSystem.B.dylib               0x00002f94 mach_msg + 60
2   CoreFoundation                  0x00074b18 __CFRunLoopServiceMachPort + 88
3   CoreFoundation                  0x000770e0 __CFRunLoopRun + 400
4   CoreFoundation                  0x0001e0bc CFRunLoopRunSpecific + 220
5   CoreFoundation                  0x0001dfca CFRunLoopRunInMode + 54
6   Foundation                      0x0003c316 +[NSURLConnection(NSURLConnectionReallyInternal) _resourceLoadLoop:] + 210
7   Foundation                      0x0000c612 -[NSThread main] + 42
8   Foundation                      0x00092140 __NSThread__main__ + 908
9   libSystem.B.dylib               0x0008af80 _pthread_start + 364
10  libSystem.B.dylib               0x0007d014 thread_start + 0

Thread 4:
0   libSystem.B.dylib               0x00029f24 select$DARWIN_EXTSN + 20
1   CoreFoundation                  0x0007aa54 __CFSocketManager + 340
2   libSystem.B.dylib               0x0008af80 _pthread_start + 364
3   libSystem.B.dylib               0x0007d014 thread_start + 0

I don't know what is causing the objc_msgSend crash, or how it is related to StoreKit. I also have no idea what I added or changed which caused this simple code to stop working.

Answer 1

A very likely explanation is whether the object you set as a delegate for the SKProductRequest object might have been deallocated already.

It is quite possible for the request to take a few seconds to complete, and this might be past the lifetime of your delegate object, so you may want to make sure it sticks around for long enough.

Answer 2

The answer above is technically correct but it is not complete. As Megastep said "the object you set as the delegate for the SKProductsRequest may have already been deallocated." Therefore you are sending a message to an object that has already been deallocated. Now onto the actual answer:

- (void)requestProUpgradeProductData {
    NSSet *productIdentifiers = //Your Product IDs go here

    productsRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:productIdentifiers];
    productsRequest.delegate = self;
    [productsRequest start];

    // we will release the request object in the delegate callback
}

#pragma mark -
#pragma mark SKProductRequest Delegate Methods

- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse(SKProductsResponse *)response {
self.products = response.products;
//NSLog(@"%i",[products count]);
proUpgradeProduct = [products count] == 4 ? [[products objectAtIndex:0] retain] : nil;
if (proUpgradeProduct)
{
    //Do your stuff here...
}

for (NSString *invalidProductId in response.invalidProductIdentifiers)
{
    //NSLog(@"Invalid product id: %@" , invalidProductId);
}

// finally release the reqest we alloc/init’ed in requestProUpgradeProductData
[productsRequest release];

[[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerProductsFetchedNotification object:self userInfo:nil];
}

So basically as you can see above you do not need to release productsRequest because it is already being released in the delegate callback method. Again you do not need to call productsRequest release or set it Nil in viewDidUnload/dealloc method because that could cause a crash if you dismiss the view before the callback method gets called.