What is this crash about? Is this from the OS side?

Question

tooPick OP

Created Jul ’23

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Participants 2

I have this exception backtrace in my app. I'm not sure if this crash is from my implementation or from the OS.

From the frame 2 we can see that this is the one that throwing exception, but I still have no idea about it.

Does anyone can help?

Thanks

Here is the back complete crash log and the backtrace:

2023-07-20_10-12-23.5237_+0700-e3c7635495de265f5efcc92a0d27dd1d0f7bede7.crash

Last Exception Backtrace:
0   CoreFoundation                    0x1b6838d78 __exceptionPreprocess + 220 (NSException.m:200)
1   libobjc.A.dylib                   0x1cf49d734 objc_exception_throw + 60 (objc-exception.mm:565)
2   CoreFoundation                    0x1b6890024 +[NSException raise:format:] + 112 (NSException.m:156)
3   UIKitCore                         0x1b9617e20 -[UIDocument writeContents:toURL:forSaveOperation:originalContentsURL:error:] + 616 (UIDocument.m:1329)
4   UIKitCore                         0x1b9617a9c -[UIDocument writeContents:andAttributes:safelyToURL:forSaveOperation:error:] + 492 (UIDocument.m:1286)
5   UIKitCore                         0x1b9619264 __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke_3 + 224 (UIDocument.m:1490)
6   UIKitCore                         0x1b96190cc __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke_2 + 380 (UIDocument.m:1524)
7   UIKitCore                         0x1b961865c __59-[UIDocument _coordinateWritingItemAtURL:error:byAccessor:]_block_invoke.623 + 184 (UIDocument.m:1407)
8   Foundation                        0x1b803cf98 -[NSFileCoordinator _invokeAccessor:thenCompletionHandler:] + 100 (NSFileCoordinator.m:430)
9   Foundation                        0x1b8083774 __73-[NSFileCoordinator coordinateWritingItemAtURL:options:error:byAccessor:]_block_invoke + 132 (NSFileCoordinator.m:473)
10  Foundation                        0x1b8194e30 __85-[NSFileCoordinator(NSPrivate) _coordinateWritingItemAtURL:options:error:byAccessor:]_block_invoke.350 + 264 (NSFileCoordinator.m:1083)
11  Foundation                        0x1b8073538 -[NSFileCoordinator(NSPrivate) _withAccessArbiter:invokeAccessor:orDont:andRelinquishAccessClaim:] + 620 (NSFileCoordinator.m:960)
12  Foundation                        0x1b80866c0 -[NSFileCoordinator(NSPrivate) _coordinateWritingItemAtURL:options:error:byAccessor:] + 784 (NSFileCoordinator.m:1080)
13  Foundation                        0x1b7fa0710 -[NSFileCoordinator coordinateWritingItemAtURL:options:error:byAccessor:] + 120 (NSFileCoordinator.m:472)
14  UIKitCore                         0x1b9618288 -[UIDocument _coordinateWritingItemAtURL:error:byAccessor:] + 472 (UIDocument.m:1404)
15  UIKitCore                         0x1b9618cd8 __59-[UIDocument saveToURL:forSaveOperation:completionHandler:]_block_invoke + 336 (UIDocument.m:1476)
16  libdispatch.dylib                 0x1b649de68 _dispatch_call_block_and_release + 32 (init.c:1517)
17  libdispatch.dylib                 0x1b649fa2c _dispatch_client_callout + 20 (object.m:560)
18  libdispatch.dylib                 0x1b64a7124 _dispatch_lane_serial_drain + 668 (inline_internal.h:2622)
19  libdispatch.dylib                 0x1b64a7c80 _dispatch_lane_invoke + 392 (queue.c:3944)
20  libdispatch.dylib                 0x1b64b2500 _dispatch_workloop_worker_thread + 648 (queue.c:6732)
21  libsystem_pthread.dylib           0x2278420bc _pthread_wqthread + 288 (pthread.c:2599)
22  libsystem_pthread.dylib           0x227841e5c start_wqthread + 8 (:-1)

Boost

Answer 1

Frameworks Engineer OP

Apple

Jul ’23

The one thing missing – the exception message – is probably the one thing you need to understand what is going wrong here. This report is from iOS 15.4, but I would be the two exception cases in UIDocument in this method remain the same:

"The default implementation of -[UIDocument writeContents:toURL:forSaveOperation:originalContentsURL:error: only understands contents of type NSFileWrapper or NSData, not <class of the contents>. You must override one of the write methods to support custom content types"

-- or --

"-[UIDocument writeContents:toURL:forSaveOperation:originalContentsURL:error:] must be overridden for your application to support non-'file:' URLs."

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