Hi, I have been looking into Core Data crashes happening when the app is in background and fault is fired due to some processing happening within the app. The stack looks like this where the line 5 just accesses a property of the NSManagedObject's subclass. Unfortunately I don't see any additional information about the exception itself. Therefore, I was wondering if anyone could shed some light on which exception the NSFaultHandler.m:395 is triggering and why. Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Triggered by Thread: 10 Last Exception Backtrace: 0 CoreFoundation 0x1d15b8e38 __exceptionPreprocess + 164 (NSException.m:202) 1 libobjc.A.dylib 0x1ca7478d8 objc_exception_throw + 60 (objc-exception.mm:356) 2 CoreData 0x1d8dda27c _PFFaultHandlerLookupRow + 2508 (NSFaultHandler.m:395) 3 CoreData 0x1d8e024e0 _PF_FulfillDeferredFault + 200 (NSFaultHandler.m:915) 4 CoreData 0x1d8eb8f1c _sharedIMPL_pvfk_core + 168 (NSManagedObject_Accessors.m:1198) 5 MyApp 0x103641928 closure #8 in static ChatChannel.create(fromDTO:depth:) + 304 (ChannelDTO.swift:531) At first I was thinking if this could be a case of accessing a deleted object while the context is still referencing it, but does not look like it. At least I can't reproduce it (tried deleting objects using a separate context and even with container but no crash happens). Happy to learn about different cases what could trigger exception with this stack. Notes: Contexts I use are all created with newBackgroundContext method.

I have been investigating a crash where saving a context leads to a crash triggered internally by Core Data. Is there any information on what exception or fatal error it is? Or any hint of any kind which leads to NSManagedObjectContext.m:1475 (seems like this line calls abort or some sort of fatal error). Seems like this happens when the app is in background. Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000019266a3f8 Termination Reason: SIGNAL 5 Trace/BPT trap: 5 Terminating Process: exc handler [38173] Triggered by Thread: 9 … Thread 9 Crashed: 0 CoreData 0x000000019266a3f8 -[NSManagedObjectContext _thereIsNoSadnessLikeTheDeathOfOptimism] + 36 (NSManagedObjectContext.m:1475) 1 CoreData 0x00000001925c8fa0 -[NSManagedObjectContext save:] + 1844 (NSManagedObjectContext.m:1688) 2 MyApp 0x0000000102cc747c closure #1 in DatabaseContainer.write(_:completion:) (in MyApp) (DatabaseContainer.swift:233) + 7861372 3 MyApp 0x0000000102baab14 thunk for @escaping @callee_guaranteed () -> () (in MyApp) (<compiler-generated>:0) + 6695700 4 CoreData 0x000000019252dfe8 developerSubmittedBlockToNSManagedObjectContextPerform + 156 (NSManagedObjectContext.m:3985) 5 libdispatch.dylib 0x00000001922e2dd4 _dispatch_client_callout + 20 (object.m:576) 6 libdispatch.dylib 0x00000001922ea400 _dispatch_lane_serial_drain + 748 (queue.c:3900) 7 libdispatch.dylib 0x00000001922eaf30 _dispatch_lane_invoke + 380 (queue.c:3991) 8 libdispatch.dylib 0x00000001922f5cb4 _dispatch_root_queue_drain_deferred_wlh + 288 (queue.c:6998) 9 libdispatch.dylib 0x00000001922f5528 _dispatch_workloop_worker_thread + 404 (queue.c:6592) 10 libsystem_pthread.dylib 0x00000001e6e8c934 _pthread_wqthread + 288 (pthread.c:2696) 11 libsystem_pthread.dylib 0x00000001e6e890cc start_wqthread + 8 (:-1)