I see random crashes while executing the BackendlessDataQuery (even a simple query). In my scenario, i have a TableViewController where I update the results during viewDidLoad and pull to refresh. I see random crashes when the user tries to refresh the table view using pull to refresh (sometimes even during viewDidLoad). One thing common during all these crashes is the error message.
I tried to replicate the same using a very simple app which has a UIButton to execute the query and print the data count. When you click on the button 4 - 5 times consecutively, the app crashes with the following error message.
2016-05-02 23:21:11.144 RelationEntrySave[37624:1299536] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSDictionary objectForKey:]: method only defined for abstract class. Define -[NSMutableDictionary objectForKey:]!'
*** First throw call stack:
(
0 CoreFoundation 0x0000000104d76d85 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010510bdeb objc_exception_throw + 48
2 CoreFoundation 0x0000000104d8079f __CFRequireConcreteImplementation + 271
3 CoreFoundation 0x0000000104d73387 -[NSDictionary objectForKey:] + 39
4 RelationEntrySave 0x0000000100dd86c7 -[HttpEngine processAsyncAMFResponse:] + 1264
5 libdispatch.dylib 0x0000000105bbed9d _dispatch_call_block_and_release + 12
6 libdispatch.dylib 0x0000000105bdf3eb _dispatch_client_callout + 8
7 libdispatch.dylib 0x0000000105bc71ef _dispatch_main_queue_callback_4CF + 1738
8 CoreFoundation 0x0000000104cd00f9 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
9 CoreFoundation 0x0000000104c91b99 __CFRunLoopRun + 2073
10 CoreFoundation 0x0000000104c910f8 CFRunLoopRunSpecific + 488
11 GraphicsServices 0x0000000107460ad2 GSEventRunModal + 161
12 UIKit 0x00000001036abf09 UIApplicationMain + 171
13 RelationEntrySave 0x0000000100dd6d22 main + 114
14 libdyld.dylib 0x0000000105c1392d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException