问题
I'm facing a rather odd problem. With subclassing some NSViews, NSTableView and NSScrollView to be specific.
Situation: I'm working on a quite old (ca. 7 year) project for macOS. The codebase is about 50% objc and 50% swift 3.2 and uses XIB files for the individual views. The application runs smoothly on 10.10 - 10.12 but it crashes on 10.13 pretty much instantly.
The backtrace shows the following:
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x00007fff50490b05 Foundation`_NSKVONotifyingCreateInfoWithOriginalClass + 177
frame #1: 0x00007fff50490a35 Foundation`_NSKeyValueContainerClassGetNotifyingInfo + 59
frame #2: 0x00007fff504908c4 Foundation`-[NSKeyValueUnnestedProperty _isaForAutonotifying] + 75
frame #3: 0x00007fff5049075f Foundation`-[NSKeyValueUnnestedProperty isaForAutonotifying] + 75
frame #4: 0x00007fff5048f9fb Foundation`-[NSObject(NSKeyValueObserverRegistration) _addObserver:forProperty:options:context:] + 490
frame #5: 0x00007fff5048e7c9 Foundation`-[NSObject(NSKeyValueObserverRegistration) addObserver:forKeyPath:options:context:] + 103
frame #6: 0x00007fff504da865 Foundation`-[NSKeyValueNestedProperty object:withObservance:didChangeValueForKeyOrKeys:recurse:forwardingValues:] + 411
frame #7: 0x00007fff504af6d8 Foundation`NSKeyValueDidChange + 179
frame #8: 0x00007fff505eb370 Foundation`NSKeyValueDidChangeWithPerThreadPendingNotifications + 132
frame #9: 0x00007fff4c2ac3a0 AppKit`-[NSView didChangeValueForKey:] + 93
frame #10: 0x00007fff504aff4d Foundation`NSKeyValueNotifyObserver + 350
frame #11: 0x00007fff504af800 Foundation`NSKeyValueDidChange + 475
frame #12: 0x00007fff505eb370 Foundation`NSKeyValueDidChangeWithPerThreadPendingNotifications + 132
frame #13: 0x00007fff4c2ac3a0 AppKit`-[NSView didChangeValueForKey:] + 93
frame #14: 0x00007fff4bbf6877 AppKit`-[NSScrollView _makeUnderTitlebarView] + 165
frame #15: 0x00007fff4b9e9eff AppKit`-[NSScrollView _updateStateOfUnderTitlebarView] + 327
frame #16: 0x00007fff4bae5ef1 AppKit`-[NSScrollView viewDidMoveToWindow] + 113
frame #17: 0x00007fff4b9e82b2 AppKit`-[NSView _setWindow:] + 2867
frame #18: 0x00007fff4b9efe9d AppKit`-[NSScrollView _setWindow:] + 500
frame #19: 0x00007fff4e3ef79f CoreFoundation`-[__NSArrayM enumerateObjectsWithOptions:usingBlock:] + 239
frame #20: 0x00007fff4c2acfed AppKit`__21-[NSView _setWindow:]_block_invoke.604 + 141
frame #21: 0x00007fff504c9b4a Foundation`-[NSISEngine withBehaviors:performModifications:] + 131
frame #22: 0x00007fff4b9e602d AppKit`-[NSView(NSConstraintBasedLayout) _withAutomaticEngineOptimizationDisabled:] + 70
frame #23: 0x00007fff4b9e8203 AppKit`-[NSView _setWindow:] + 2692
frame #24: 0x00007fff4b9e52d5 AppKit`-[NSView addSubview:] + 257
frame #25: 0x00007fff4ba1e228 AppKit`-[NSFrameView addSubview:] + 44
frame #26: 0x00007fff4ba1e1ed AppKit`-[NSThemeFrame addSubview:] + 381
frame #27: 0x00007fff4ba1df1a AppKit`-[NSView addSubview:positioned:relativeTo:] + 214
frame #28: 0x00007fff4c2593bd AppKit`-[NSThemeFrame addSubview:positioned:relativeTo:] + 42
frame #29: 0x00007fff4ba1de37 AppKit`-[NSThemeFrame _addKnownSubview:positioned:relativeTo:] + 38
frame #30: 0x00007fff4ba43853 AppKit`-[NSWindow setContentView:] + 382
frame #31: 0x000000010007e8da MyApp`-[Document someContentViewItemSelected:](self=0x000060403b97eef0, _cmd="someContentViewItemSelected:", sender=0x0000604043fb0f60) at Document.m:230
The backtrace is not very helpful (but maybe I'm missing something), but the error occurs when the view of a new ViewController gets assigned to the window sheet's content view self.windowForSheet.contentView = contentViewController.view.
Problem: The view of that controller has a NSTableview, which I subclassed and assigned the class in the interface builder to the table object. If I remove this subclass, everything works fine.
What I tried:
I tried to reproduce the problem with completely empty subclasses written in objc and swift and with both, the problem occurs and the app crashes with the exact same backtrace.
I tried creating a new app utilising xib with the view controller and a subclassed NSTableView and it works just fine!
I tried compiling the app with Xcode 8.3.3 (on 10.12 & 10.13)and 9.1 (on10.13) and the resulting apps show the same behaviour, working fine on 10.12, 10.11 but crashes on 10.13.
I assume it all has to do with it being a very old project with mixed languages and outdated xib files, but I can't point my fingers at specifics.
Question: Do you guys know what this problem could be? Have had problems with subclassing NSTableView or NSScrollView (NSTableViewCell subclasses work just fine by the way).
I appreciate every help or input you can give me. Thank you
回答1:
Try to update old frameworks. I had the same problem with Sparkle. Updating from 1.8.0 to 1.18.1 have solved two similar bugs.
(ca. 7 year) project for macOS.
It's sad, but haven't found the exact commit in Sparkle that has fixed the crash. I think it is between versions 1.8.0 and 1.9.0. Please let me know if you find the exact line of code caused the crash.
来源：https://stackoverflow.com/questions/47140229/macos-10-13-exec-bad-access-caused-by-subclassing-nstableview-or-nsscrollview