Crashes in Widgets

[caseywagner88]

My team is seeing crashes in our widgets and the stack traces all seem to point to some SQL/database operations happening inside Mixpanel. Take a look at thread 4. We have many variants of this crash with similar traces.

Any thoughts on this crash? And more generally - is there any documentation available that details how to use Mixpanel in widgets?

Thread 0 name:
Thread 0 Crashed:
0   libsystem_kernel.dylib        	0x00000001ec2c1af8 mach_msg2_trap + 8 (:-1)
1   libsystem_kernel.dylib        	0x00000001ec2c1890 mach_msg2_internal + 80 (mach_msg.c:201)
2   libsystem_kernel.dylib        	0x00000001ec2c17a8 mach_msg_overwrite + 436 (mach_msg.c:0)
3   libsystem_kernel.dylib        	0x00000001ec2c15e8 mach_msg + 24 (mach_msg.c:323)
4   CoreFoundation                	0x00000001a3d9c01c __CFRunLoopServiceMachPort + 160 (CFRunLoop.c:2624)
5   CoreFoundation                	0x00000001a3d99f04 __CFRunLoopRun + 1208 (CFRunLoop.c:3007)
6   CoreFoundation                	0x00000001a3d99968 CFRunLoopRunSpecific + 608 (CFRunLoop.c:3420)
7   Foundation                    	0x00000001a2c284a8 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 212 (NSRunLoop.m:373)
8   Foundation                    	0x00000001a2c26ff0 -[NSRunLoop(NSRunLoop) run] + 64 (NSRunLoop.m:398)
9   libxpc.dylib                  	0x00000001ffda626c _xpc_objc_main + 336 (main.m:267)
10  libxpc.dylib                  	0x00000001ffda87e4 _xpc_main + 64 (init.c:1294)
11  libxpc.dylib                  	0x00000001ffda87a4 xpc_bs_main + 16 (init.c:1310)
12  BoardServices                 	0x00000001bca34240 +[BSServicesConfiguration activateXPCService] + 68 (BSServicesConfiguration.m:113)
13  ExtensionFoundation           	0x00000001b2db7df0 -[_EXRunningExtension resume] + 260 (EXRunningExtension.m:298)
14  ExtensionFoundation           	0x00000001b2db7c38 -[_EXRunningExtension startWithArguments:count:] + 396 (EXRunningExtension.m:269)
15  ExtensionFoundation           	0x00000001b2dcba30 EXExtensionMain + 220 (EXExtensionMain.m:34)
16  Foundation                    	0x00000001a3361ed4 NSExtensionMain + 204 (NSExtensionMain.m:21)
17  dyld                          	0x00000001c72bad84 start + 2240 (dyldMain.cpp:1298)

Thread 1:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

Thread 2:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

Thread 3:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

Thread 4 name:
Thread 4:
0   libsystem_kernel.dylib        	0x00000001ec2cf81c guarded_pwrite_np + 8 (:-1)
1   libsqlite3.dylib              	0x00000001cdad8158 seekAndWrite + 456 (sqlite3.c:44255)
2   libsqlite3.dylib              	0x00000001cda91908 unixWrite + 180 (sqlite3.c:44333)
3   libsqlite3.dylib              	0x00000001cdae0574 pagerWalFrames + 868 (sqlite3.c:66940)
4   libsqlite3.dylib              	0x00000001cda91628 sqlite3PagerCommitPhaseOne + 316 (sqlite3.c:70256)
5   libsqlite3.dylib              	0x00000001cda81d7c sqlite3BtreeCommitPhaseOne + 172 (sqlite3.c:80934)
6   libsqlite3.dylib              	0x00000001cda81944 vdbeCommit + 1136 (sqlite3.c:93952)
7   libsqlite3.dylib              	0x00000001cda5ac74 sqlite3VdbeHalt + 1352 (sqlite3.c:94362)
8   libsqlite3.dylib              	0x00000001cda7bb64 sqlite3VdbeExec + 42536 (sqlite3.c:101084)
9   libsqlite3.dylib              	0x00000001cda70c80 sqlite3_step + 964 (sqlite3.c:97699)
10  App WidgetExtension         	0x0000000102950448 closure #1 in MPDB.insertRow(_:data:flag:) + 448 (MPDB.swift:169)
11  App WidgetExtension         	0x000000010295021c specialized __DataStorage.withUnsafeBytes<A>(in:apply:) + 16 (<compiler-generated>:0)
12  App WidgetExtension         	0x000000010295021c specialized Data._Representation.withUnsafeBytes<A>(_:) + 212 (<compiler-generated>:0)
13  App WidgetExtension         	0x000000010295021c specialized Data.withUnsafeBytes<A>(_:) + 212 (MPDB.swift:0)
14  App WidgetExtension         	0x000000010295021c MPDB.insertRow(_:data:flag:) + 692
15  App WidgetExtension         	0x000000010296f968 MixpanelPersistence.saveEntity(_:type:flag:) + 60 (MixpanelPersistence.swift:73)
16  App WidgetExtension         	0x000000010296f968 closure #1 in People.addPeopleRecordToQueueWithAction(_:properties:) + 2640 (People.swift:95)
17  App WidgetExtension         	0x000000010295303c thunk for @escaping @callee_guaranteed @Sendable () -> () + 28
18  libdispatch.dylib             	0x00000001abc6113c _dispatch_call_block_and_release + 32 (init.c:1530)
19  libdispatch.dylib             	0x00000001abc62dd4 _dispatch_client_callout + 20 (object.m:576)
20  libdispatch.dylib             	0x00000001abc6a400 _dispatch_lane_serial_drain + 748 (queue.c:3900)
21  libdispatch.dylib             	0x00000001abc6af64 _dispatch_lane_invoke + 432 (queue.c:3991)
22  libdispatch.dylib             	0x00000001abc75cb4 _dispatch_root_queue_drain_deferred_wlh + 288 (queue.c:6998)
23  libdispatch.dylib             	0x00000001abc75528 _dispatch_workloop_worker_thread + 404 (queue.c:6592)
24  libsystem_pthread.dylib       	0x00000001ffd48f20 _pthread_wqthread + 288 (pthread.c:2665)
25  libsystem_pthread.dylib       	0x00000001ffd48fc0 start_wqthread + 8 (:-1)

Thread 5 name:
Thread 5:
0   libsystem_kernel.dylib        	0x00000001ec2c1af8 mach_msg2_trap + 8 (:-1)
1   libsystem_kernel.dylib        	0x00000001ec2c1890 mach_msg2_internal + 80 (mach_msg.c:201)
2   libsystem_kernel.dylib        	0x00000001ec2c17a8 mach_msg_overwrite + 436 (mach_msg.c:0)
3   libsystem_kernel.dylib        	0x00000001ec2c15e8 mach_msg + 24 (mach_msg.c:323)
4   CoreFoundation                	0x00000001a3d9c01c __CFRunLoopServiceMachPort + 160 (CFRunLoop.c:2624)
5   CoreFoundation                	0x00000001a3d99f04 __CFRunLoopRun + 1208 (CFRunLoop.c:3007)
6   CoreFoundation                	0x00000001a3d99968 CFRunLoopRunSpecific + 608 (CFRunLoop.c:3420)
7   CFNetwork                     	0x00000001a50f8c48 +[__CFN_CoreSchedulingSetRunnable _run:] + 384 (CoreSchedulingSet.mm:1479)
8   Foundation                    	0x00000001a2c99a9c __NSThread__start__ + 732 (NSThread.m:991)
9   libsystem_pthread.dylib       	0x00000001ffd49a90 _pthread_start + 136 (pthread.c:927)
10  libsystem_pthread.dylib       	0x00000001ffd48fcc thread_start + 8 (:-1)

Thread 6:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

Thread 7:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

Thread 8:
0   libsystem_pthread.dylib       	0x00000001ffd48fb8 start_wqthread + 0 (:-1)

[jaredmixpanel]

@caseywagner88 This SDK doesn't have proper support for Widgets (App Group support). The crash occurs because iOS widget extensions run in a separate sandboxed environment from your main app. When the SDK tries to track events from within a widget, it attempts to write to a SQLite database located in the main app's file system, which widget extensions cannot access due to iOS security restrictions. To prevent the crash you'll either need to remove the Mixpanel code from your widget or if it's shared code, wrap your Mixpanel imports and tracking code in custom compilation flags, something like:

  #if !WIDGET_EXTENSION
  import Mixpanel
  #endif

  #if !WIDGET_EXTENSION
  Mixpanel.mainInstance().track(event: "My Event")
  #endif

Or you could use a helper function like...

func isInWidget() -> Bool {
    guard let extensionInfo = Bundle.main.infoDictionary?["NSExtension"] as? [String: Any],
          let extensionPointIdentifier = extensionInfo["NSExtensionPointIdentifier"] as? String else {
        return false
    }
    return extensionPointIdentifier == "com.apple.widgetkit-extension"
}

I'll leave this issue open until we can implement proper App Group support in the SDK.