macos - 为什么我的 FinderSync 扩展在启动之前就崩溃了？

Question

每次 FinderSync 扩展启动时，我都会遇到此崩溃:

Process:               My Finder Sync [8364]
Path:                  /Applications/Company/Container.app/Contents/PlugIns/My Finder Sync.appex/Contents/MacOS/My Finder Sync
Identifier:            com.company.Container.My-Finder-Sync
Version:               [Set on build machine] ([Set on build machine])
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           My Finder Sync [8364]
User ID:               1129915948

Date/Time:             2019-01-04 11:31:34.146 -0500
OS Version:            Mac OS X 10.13.6 (17G4015)
Report Version:        12
Anonymous UUID:        013E2942-CED9-22FA-438A-E3D0BA89EB5C

Sleep/Wake UUID:       D21EDE9D-237A-412A-8456-B96453886BAD

Time Awake Since Boot: 3200 seconds
Time Since Wake:       2600 seconds

System Integrity Protection: disabled

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

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSDictionaryM setObject:forKey:]: object cannot be nil (key: 37990439-1DFE-4F0B-9865-6FC1D34A3BE4)'
terminating with uncaught exception of type NSException
abort() called

Application Specific Backtrace 1:
0   CoreFoundation                      0x00007fff31eb523b __exceptionPreprocess + 171
1   libobjc.A.dylib                     0x00007fff59147c76 objc_exception_throw + 48
2   CoreFoundation                      0x00007fff31ef64c4 _CFThrowFormattedException + 202
3   CoreFoundation                      0x00007fff31db87cc -[__NSDictionaryM setObject:forKey:] + 1020
4   Foundation                          0x00007fff3408b348 -[_NSExtensionContextVendor _setPrincipalObject:forUUID:] + 106
5   Foundation                          0x00007fff3408ab04 __105-[_NSExtensionContextVendor _beginRequestWithExtensionItems:listenerEndpoint:withContextUUID:completion:]_block_invoke + 804
6   libdispatch.dylib                   0x00007fff59d2f5fa _dispatch_call_block_and_release + 12
7   libdispatch.dylib                   0x00007fff59d27db8 _dispatch_client_callout + 8
8   libdispatch.dylib                   0x00007fff59d33395 _dispatch_main_queue_callback_4CF + 1148
9   CoreFoundation                      0x00007fff31e6db39 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
10  CoreFoundation                      0x00007fff31e2fcda __CFRunLoopRun + 2586
11  CoreFoundation                      0x00007fff31e2f033 CFRunLoopRunSpecific + 483
12  HIToolbox                           0x00007fff31119d96 RunCurrentEventLoopInMode + 286
13  HIToolbox                           0x00007fff31119b06 ReceiveNextEventCommon + 613
14  HIToolbox                           0x00007fff31119884 _BlockUntilNextEventMatchingListInModeWithFilter + 64
15  AppKit                              0x00007fff2f3c9a73 _DPSNextEvent + 2085
16  AppKit                              0x00007fff2fb5fe34 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
17  AppKit                              0x00007fff2f3be885 -[NSApplication run] + 764
18  AppKit                              0x00007fff2f38da72 NSApplicationMain + 804
19  libxpc.dylib                        0x00007fff5a0bbd77 _xpc_objc_main + 580
20  libxpc.dylib                        0x00007fff5a0ba9ca xpc_main + 433
21  Foundation                          0x00007fff33f825f5 +[NSXPCListener serviceListener] + 0
22  PlugInKit                           0x00007fff50ddbf8d -[PKService run] + 704
23  PlugInKit                           0x00007fff50ddbb99 +[PKService main] + 55
24  PlugInKit                           0x00007fff50ddbfb1 +[PKService _defaultRun:arguments:] + 17
25  Foundation                          0x00007fff34130229 NSExtensionMain + 51
26  libdyld.dylib                       0x00007fff59d61015 start + 1
27  ???                                 0x0000000000000001 0x0 + 1

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib          0x00007fff59eb1b66 __pthread_kill + 10
1   libsystem_pthread.dylib         0x00007fff5a07c080 pthread_kill + 333
2   libsystem_c.dylib               0x00007fff59e0d1ae abort + 127
3   libc++abi.dylib                 0x00007fff57d07f8f abort_message + 245
4   libc++abi.dylib                 0x00007fff57d0812b default_terminate_handler() + 265
5   libobjc.A.dylib                 0x00007fff59149ea3 _objc_terminate() + 97
6   libc++abi.dylib                 0x00007fff57d237c9 std::__terminate(void (*)()) + 8
7   libc++abi.dylib                 0x00007fff57d23843 std::terminate() + 51
8   libdispatch.dylib               0x00007fff59d27dcc _dispatch_client_callout + 28
9   libdispatch.dylib               0x00007fff59d33395 _dispatch_main_queue_callback_4CF + 1148
10  com.apple.CoreFoundation        0x00007fff31e6db39 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
11  com.apple.CoreFoundation        0x00007fff31e2fcda __CFRunLoopRun + 2586
12  com.apple.CoreFoundation        0x00007fff31e2f033 CFRunLoopRunSpecific + 483
13  com.apple.HIToolbox             0x00007fff31119d96 RunCurrentEventLoopInMode + 286
14  com.apple.HIToolbox             0x00007fff31119b06 ReceiveNextEventCommon + 613
15  com.apple.HIToolbox             0x00007fff31119884 _BlockUntilNextEventMatchingListInModeWithFilter + 64
16  com.apple.AppKit                0x00007fff2f3c9a73 _DPSNextEvent + 2085
17  com.apple.AppKit                0x00007fff2fb5fe34 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
18  com.apple.AppKit                0x00007fff2f3be885 -[NSApplication run] + 764
19  com.apple.AppKit                0x00007fff2f38da72 NSApplicationMain + 804
20  libxpc.dylib                    0x00007fff5a0bbd77 _xpc_objc_main + 580
21  libxpc.dylib                    0x00007fff5a0ba9ca xpc_main + 433
22  com.apple.Foundation            0x00007fff33f825f5 -[NSXPCListener resume] + 165
23  com.apple.pluginkit.framework   0x00007fff50ddbf8d -[PKService run] + 704
24  com.apple.pluginkit.framework   0x00007fff50ddbb99 +[PKService main] + 55
25  com.apple.pluginkit.framework   0x00007fff50ddbfb1 +[PKService _defaultRun:arguments:] + 17
26  com.apple.Foundation            0x00007fff34130229 NSExtensionMain + 51
27  libdyld.dylib                   0x00007fff59d61015 start + 1

Thread 1:
0   libsystem_kernel.dylib          0x00007fff59eb228a __workq_kernreturn + 10
1   libsystem_pthread.dylib         0x00007fff5a079009 _pthread_wqthread + 1035
2   libsystem_pthread.dylib         0x00007fff5a078be9 start_wqthread + 13

Thread 2:
0   libsystem_kernel.dylib          0x00007fff59eb228a __workq_kernreturn + 10
1   libsystem_pthread.dylib         0x00007fff5a079009 _pthread_wqthread + 1035
2   libsystem_pthread.dylib         0x00007fff5a078be9 start_wqthread + 13

Thread 3:
0   libsystem_kernel.dylib          0x00007fff59eb228a __workq_kernreturn + 10
1   libsystem_pthread.dylib         0x00007fff5a079009 _pthread_wqthread + 1035
2   libsystem_pthread.dylib         0x00007fff5a078be9 start_wqthread + 13

Thread 4:
0   libsystem_pthread.dylib         0x00007fff5a078bdc start_wqthread + 0
1   ???                             0x0004000200000006 0 + 1125908496777222

Thread 5:: com.apple.NSEventThread
0   libsystem_kernel.dylib          0x00007fff59ea820a mach_msg_trap + 10
1   libsystem_kernel.dylib          0x00007fff59ea7724 mach_msg + 60
2   com.apple.CoreFoundation        0x00007fff31e30665 __CFRunLoopServiceMachPort + 341
3   com.apple.CoreFoundation        0x00007fff31e2f9b7 __CFRunLoopRun + 1783
4   com.apple.CoreFoundation        0x00007fff31e2f033 CFRunLoopRunSpecific + 483
5   com.apple.AppKit                0x00007fff2f506fc4 _NSEventThread + 184
6   libsystem_pthread.dylib         0x00007fff5a079661 _pthread_body + 340
7   libsystem_pthread.dylib         0x00007fff5a07950d _pthread_start + 377
8   libsystem_pthread.dylib         0x00007fff5a078bf9 thread_start + 13

Thread 0 crashed with X86 Thread State (64-bit):
  rax: 0x0000000000000000  rbx: 0x00007fff927a7380  rcx: 0x00007ffee31a6c68  rdx: 0x0000000000000000
  rdi: 0x0000000000000307  rsi: 0x0000000000000006  rbp: 0x00007ffee31a6ca0  rsp: 0x00007ffee31a6c68
   r8: 0x00007ffee31a6b30   r9: 0x00007ffee31a6d00  r10: 0x0000000000000000  r11: 0x0000000000000206
  r12: 0x0000000000000307  r13: 0x0000000000000030  r14: 0x0000000000000006  r15: 0x000000000000002d
  rip: 0x00007fff59eb1b66  rfl: 0x0000000000000206  cr2: 0x00007fff92784168

如您所见，其中只有 Apple 平台的内容。更糟糕的是，这种情况发生在调用我的任何代码之前!至少，它永远不会到达我的 FIFinderSync 类的 init 中的断点。

那么这是怎么回事？为什么它会因某些字典中的 UUID 键和 nil 值而崩溃？我已经检查了所有代码并确保不会发生这种情况(我确实有一些类似的字典，但所有字典都在 Swift 代码中，并且值不是可选的，因此永远不会是 nil；没关系他们的断点也没有被命中)。

Answer 1

Swift 会进行一些名称修改，即使看起来并非如此。当您执行诸如通过字符串引用类名之类的操作(例如在 FinderSync 扩展的 info.plist 中)时，在 Swift 中并不总是按预期工作。

例如，如果您有一个类:

@objc
class MyFinderSyncPrinicpalClass: FIFinderSync {
    // ...
}

尝试编译它并查看生成的 Obj-C header 。它可能看起来像这样:

SWIFT_CLASS("_TtC17My_Finder_Sync10MyFinderSyncPrinicpalClass")
@interface MyFinderSyncPrinicpalClass : FIFinderSync
// ...
@end

这意味着 Swift 和 Objective-C 代码都可以简单地将其引用为 MyFinderSyncPrinicpalClass，但任何想要通过字符串引用其编译形式的内容，例如在反射中或 info.plist，看到损坏的名称_TtC17My_Finder_Sync10MyFinderSyncPrinicpalClass。要解决此问题，只需在 @objc 注释中显式指定名称即可:

@objc(MyFinderSyncPrinicpalClass)
class MyFinderSyncPrinicpalClass: FIFinderSync {
    // ...
}

现在如果你compare that to the newly-generated Obj-C header ，你就会明白我的意思了:

SWIFT_CLASS("MyFinderSyncPrinicpalClass")
@interface MyFinderSyncPrinicpalClass : FIFinderSync
// ...
@end

现在您可以在 info.plist 中通过其实际名称来引用它，它将按预期启动!