Firestore internal assertion - wrong queue

[zporges]

[REQUIRED] Step 2: Describe your environment

• Xcode version: 10.3
• Firebase SDK version: 6.7.0
• Firebase Component: FIRESTORE
• Component version: 6.7.0

[REQUIRED] Step 3: Describe the problem

I recently updated from Firestore 6.3.0 to 6.7.0. Since then, I'm getting lots of logs of the following:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'FIRESTORE INTERNAL ASSERTION FAILED: Expected to be called by the executor associated with this queue (expected executor: 'com.google.firebase.firestore', actual executor: 'com.apple.main-thread') (expected executor_->IsCurrentExecutor())'

Steps to reproduce:

I can make the problem occur when running in simulator and turning wifi off on my Mac. But I also have logs of the exception occurring for production users on device.

Stack trace:

*** First throw call stack:
(
	0   CoreFoundation                      0x000000010c3ef8db __exceptionPreprocess + 331
	1   libobjc.A.dylib                     0x000000010afd2ac5 objc_exception_throw + 48
	2   CoreFoundation                      0x000000010c3ef662 +[NSException raise:format:arguments:] + 98
	3   Foundation                          0x000000010925c834 -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 166
	4   River Debug                         0x0000000106e6368c _ZN8firebase9firestore4util8internal4FailEPKcS4_iRKNSt3__112basic_stringIcNS5_11char_traitsIcEENS5_9allocatorIcEEEE + 268
	5   River Debug                         0x0000000106e637fa _ZN8firebase9firestore4util8internal4FailEPKcS4_iRKNSt3__112basic_stringIcNS5_11char_traitsIcEENS5_9allocatorIcEEEES4_ + 186
	6   River Debug                         0x0000000106bd788f _ZNK8firebase9firestore4util10AsyncQueue23VerifyIsCurrentExecutorEv + 223
	7   River Debug                         0x0000000106bd7ab0 _ZN8firebase9firestore4util10AsyncQueue15ExecuteBlockingERKNSt3__18functionIFvvEEE + 32
	8   River Debug                         0x0000000106bed444 _ZN8firebase9firestore6remote24ConnectivityMonitorApple21OnReachabilityChangedEj + 116
	9   River Debug                         0x0000000106becf1a _ZN8firebase9firestore6remote12_GLOBAL__N_129OnReachabilityChangedCallbackEPK23__SCNetworkReachabilityjPv + 138
	10  SystemConfiguration                 0x000000010a0fcb10 reachPerformAndUnlock + 545
	11  libdispatch.dylib                   0x000000010e8fed7f _dispatch_call_block_and_release + 12
	12  libdispatch.dylib                   0x000000010e8ffdb5 _dispatch_client_callout + 8
	13  libdispatch.dylib                   0x000000010e90d080 _dispatch_main_queue_callback_4CF + 1540
	14  CoreFoundation                      0x000000010c356a79 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
	15  CoreFoundation                      0x000000010c351126 __CFRunLoopRun + 2310
	16  CoreFoundation                      0x000000010c3504d2 CFRunLoopRunSpecific + 626
	17  GraphicsServices                    0x000000011588d2fe GSEventRunModal + 65
	18  UIKitCore                           0x0000000110c3ffc2 UIApplicationMain + 140
	19  River Debug                         0x0000000106ade3ab main + 75
	20  libdyld.dylib                       0x000000010e974541 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

[wilhuff]

Hi! This is #3661 and we released a fix for this in Firebase 6.7.1. Sorry for the trouble.