Crashes following certain operations -[GCReference compareWithReference:]

[dougsonos]

Often Gitup crashes on macOS 10.12 following certain operations that rewrite commits. I don't have a reproducible pattern yet. Attached is a crash log.

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000050
Exception Note:        EXC_CORPSE_NOTIFY

VM Regions Near 0x50:
--> 
    __TEXT                 0000000101b05000-0000000101b6b000 [  408K] r-x/rwx SM=COW  /Users/USER/Downloads/GitUp.app/Contents/MacOS/GitUp

Application Specific Information:
Performing @selector(undo:) from sender NSMenuItem 0x6000002a1380

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib          0x00007fff8f500dda __pthread_kill + 10
1   libsystem_pthread.dylib         0x00007fff8f5eb797 pthread_kill + 90
2   libsystem_c.dylib               0x00007fff8f4174d7 raise + 26
3   co.gitup.mac                    0x0000000101b2d88a 0x101b05000 + 166026
4   libsystem_platform.dylib        0x00007fff8f5ded7a _sigtramp + 26
5   ???                             000000000000000000 0 + 0
6   co.gitup.kit                    0x0000000101c13683 -[GCReference compareWithReference:] + 48
7   co.gitup.kit                    0x0000000101c137a0 -[GCReference(Extensions) isEqualToReference:] + 35
8   co.gitup.mac                    0x0000000101b1778f 0x101b05000 + 75663
9   co.gitup.kit                    0x0000000101c7b5f6 -[GIMapViewController _reloadMap:] + 764
10  com.apple.CoreFoundation        0x00007fff7a32f5dc __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
11  com.apple.CoreFoundation        0x00007fff7a32f4db _CFXRegistrationPost + 427
12  com.apple.CoreFoundation        0x00007fff7a32f242 ___CFXNotificationPost_block_invoke + 50
13  com.apple.CoreFoundation        0x00007fff7a2ed962 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 2018
14  com.apple.CoreFoundation        0x00007fff7a2ec94b _CFXNotificationPost + 667
15  com.apple.Foundation            0x00007fff7bd2b2a3 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
16  co.gitup.kit                    0x0000000101c0da2e -[GCLiveRepository _updateHistory] + 502
17  co.gitup.kit                    0x0000000101c0d4ad -[GCLiveRepository _notifyWorkingDirectoryChanged:gitDirectoryChanged:] + 329
18  co.gitup.kit                    0x0000000101c0fc44 -[GCLiveRepository _undoOperationWithReason:beforeSnapshot:afterSnapshot:checkoutIfNeeded:ignore:] + 999
19  com.apple.CoreFoundation        0x00007fff7a31732c __invoking___ + 140
20  com.apple.CoreFoundation        0x00007fff7a3171b1 -[NSInvocation invoke] + 289
21  com.apple.CoreFoundation        0x00007fff7a330316 -[NSInvocation invokeWithTarget:] + 54
22  com.apple.Foundation            0x00007fff7be020e5 -[_NSUndoStack popAndInvoke] + 235
23  com.apple.Foundation            0x00007fff7be01e8c -[NSUndoManager undoNestedGroup] + 433
24  libsystem_trace.dylib           0x00007fff8f60419d _os_activity_initiate + 61
25  com.apple.AppKit                0x00007fff786c769f -[NSApplication(NSResponder) sendAction:to:from:] + 456
26  com.apple.AppKit                0x00007fff782070ce -[NSMenuItem _corePerformAction] + 324
27  com.apple.AppKit                0x00007fff78206e3a -[NSCarbonMenuImpl performActionWithHighlightingForItemAtIndex:] + 114
28  libsystem_trace.dylib           0x00007fff8f60419d _os_activity_initiate + 61
29  com.apple.AppKit                0x00007fff78205c4e -[NSMenu performKeyEquivalent:] + 367
30  com.apple.AppKit                0x00007fff786c6281 routeKeyEquivalent + 1024
31  com.apple.AppKit                0x00007fff786c4c1d -[NSApplication(NSEvent) sendEvent:] + 3149
32  com.apple.AppKit                0x00007fff77faae8c -[NSApplication run] + 1002
33  com.apple.AppKit                0x00007fff77f75976 NSApplicationMain + 1237
34  libdyld.dylib                   0x00007fff8f3d2255 start + 1

GitUp_2016-08-02-085821.crash.txt

[AndrewHoos]

This looks like the same backtrace of a crash I have seen easiest reproduce method I have seen in 10.12:

1. Checkout master
2. Double click on master^ (one commit off of tip of branch)
3. Double click on master (current commit)

[swisspol]

Doesn't crash for me in a random repo I just tested with, so there must be some other pre-conditions.

[swisspol]

If you can repro the crash using some open source repo that be checked out, please let me know!

[swisspol]

According to Crashlytics, there were 581 crashes affecting 107 users in the past 30 days due to this very bug. This is by very very far the #1 GitUp crash.

What's interesting though is that CrashLytics reports that all the crashes happened on 10.12.

Here's an example crash:

Crashed: com.apple.main-thread
0  libsystem_platform.dylib       0x7fff9d321317 _platform_strcmp + 23
1  GitUpKit                       0x104783683 -[GCReference compareWithReference:] + 48
2  GitUpKit                       0x1047837a0 -[GCReference(Extensions) isEqualToReference:] + 35
3  GitUp                          0x10468978f -[Document mapViewControllerDidReloadGraph:] (Document.m:1513)
4  GitUpKit                       0x1047eb5f6 -[GIMapViewController _reloadMap:] + 764
5  CoreFoundation                 0x7fff8810263c __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12
6  CoreFoundation                 0x7fff8810253b _CFXRegistrationPost + 427
7  CoreFoundation                 0x7fff881022a2 ___CFXNotificationPost_block_invoke + 50
8  CoreFoundation                 0x7fff880bf9a3 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1827
9  CoreFoundation                 0x7fff880be9dc _CFXNotificationPost + 604
10 Foundation                     0x7fff89ace0e3 -[NSNotificationCenter postNotificationName:object:userInfo:] + 66
11 GitUpKit                       0x10477da2e -[GCLiveRepository _updateHistory] + 502
12 GitUpKit                       0x10477d82e -[GCLiveRepository resumeHistoryUpdates] + 53
13 GitUpKit                       0x1047df45e -[GICommitRewriterViewController finishRewritingCommitWithMessage:error:] + 762
14 GitUp                          0x104687d75 -[Document _exitRewriteWithMessage:] (Document.m:1165)
15 GitUpKit                       0x1047e0075 __43-[GICommitRewriterViewController continue:]_block_invoke + 252
16 GitUpKit                       0x1047cd0b3 __36-[GIWindowController stopModalView:]_block_invoke.192 + 32
17 libdispatch.dylib              0x7fff9d0e7f5f _dispatch_call_block_and_release + 12
18 libdispatch.dylib              0x7fff9d0df128 _dispatch_client_callout + 8
19 libdispatch.dylib              0x7fff9d0ecbb3 _dispatch_main_queue_callback_4CF + 925
20 CoreFoundation                 0x7fff8812bc89 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
21 CoreFoundation                 0x7fff880ed0ad __CFRunLoopRun + 2205
22 CoreFoundation                 0x7fff880ec5b4 CFRunLoopRunSpecific + 420
23 HIToolbox                      0x7fff8768df6c RunCurrentEventLoopInMode + 240
24 HIToolbox                      0x7fff8768dda1 ReceiveNextEventCommon + 432
25 HIToolbox                      0x7fff8768dbd6 _BlockUntilNextEventMatchingListInModeWithFilter + 71
26 AppKit                         0x7fff85d83611 _DPSNextEvent + 1093
27 AppKit                         0x7fff864938ff -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1637
28 AppKit                         0x7fff85d77fd9 -[NSApplication run] + 926
29 AppKit                         0x7fff85d42aaa NSApplicationMain + 1237
30 libdyld.dylib                  0x7fff9d115255 start + 1

[AndrewHoos]

I was able to reproduce this with the gitup repo itself

1. clone gitup with git
2. open with gitup command line too
3. double clicking origin/master^
4. double clicking origin/master

Is this potentialy related to new version of git/devtools in 10.12/Xcode beta?

[swisspol]

Are you reproducing this on 10.12? Is that from running GitUp from Xcode or using the official build? Can you paste in a full stack trace (with symbols)? Thanks.

[swisspol]

This should be fixed by 16d3848 which is in build 1019. Let me know ASAP if this crash still happens.

[AndrewHoos]

Confirmed this is fixed by 16d3848