iOS10 Open Beta-保存时iOS核心数据崩溃

Question

I am assuming it is ok to post beta iOS10 issues here, since it is an open beta. The apple forums don't come close to the help one gets on Stackoverflow.

Since the update to iOS10, our users are getting a constant crash when saving the managedObjectContext in CoreData.

This is something that has worked flawlessly since iOS 5.

It only happens on the 64 bit version of iOS10. The 32 bit version works fine.

Here is my simple save code snip:

    [self.managedObjectContext performBlockAndWait:^{
    NSError *error;
    if (![self.managedObjectContext save:&error])
    {
       NSLog(@"\n\nerror in save 1 %@\n\n", error);
    }
}];

[self.managedObjectContext performBlock:^{
    NSError *error;
    if (![_privateWriterContext save:&error])
    {
       NSLog(@"\n\nerror in save 2 %@\n\n", error);
    }
}];

(Above NSLog reports nothing, as it works in simulator).

This only fails on a 64bit device. I cannot replicate on the simulator. I also cannot replicate in debug on a device due to issues with my only 64 bit device not connecting to Xcode correctly. So I am a bit stuck.

Below is a sample stack trace reported from a user:

    Incident Identifier: 7A8DD23B-48A2-4ABF-88E7-67F1E6CDA8D5
CrashReporter Key:   5454e7c7b99a94cd75b6adfa8334bbdf10b859eb
Hardware Model:      iPhone8,1
Code Type:           ARM-64 (Native)
Role:                Foreground
Parent Process:      launchd [1]



Date/Time:           2016-07-20 22:23:00.1429 -0400
Launch Time:         2016-07-20 22:21:30.6058 -0400
OS Version:          iPhone OS 10.0 (14A5309d)
Report Version:      104

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000985e4beb8
Triggered by Thread:  0

Thread 0 name:
Thread 0 Crashed:
0   libobjc.A.dylib                 0x00000001850e6eb0 objc_msgSend + 16
1   CoreFoundation                  0x0000000185a76740 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20 (CFNotificationCenter.c:650)
2   CoreFoundation                  0x0000000185a75e44 _CFXRegistrationPost + 400 (CFNotificationCenter.c:164)
3   CoreFoundation                  0x0000000185a75bc0 ___CFXNotificationPost_block_invoke + 60 (CFNotificationCenter.c:1031)
4   CoreFoundation                  0x0000000185ae40cc -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1504 (CFXNotificationRegistrar.m:163)
5   CoreFoundation                  0x00000001859b9484 _CFXNotificationPost + 376 (CFNotificationCenter.c:1028)
6   Foundation                      0x000000018644e9dc -[NSNotificationCenter postNotificationName:object:userInfo:] + 68 (NSNotification.m:482)
7   CoreData                        0x0000000187e1dbf4 -[NSManagedObjectContext(_NSInternalNotificationHandling) _postContextDidSaveNotificationWithUserInfo:] + 880 (NSManagedObjectContext.m:7381)
8   CoreData                        0x0000000187dabb4c -[NSManagedObjectContext(_NSInternalAdditions) _didSaveChanges] + 2156 (NSManagedObjectContext.m:5827)
9   CoreData                        0x0000000187d98570 -[NSManagedObjectContext save:] + 3440 (NSManagedObjectContext.m:1532)
10  App                             0x000000010008db34 __29-[RPSAppDelegate saveContext]_block_invoke227 + 52 (RPSAppDelegate.m:338)
11  CoreData                        0x0000000187e17c68 developerSubmittedBlockToNSManagedObjectContextPerform + 168 (NSManagedObjectContext.m:3529)
12  libdispatch.dylib               0x0000000185525784 _dispatch_client_callout + 16 (object.m:455)
13  libdispatch.dylib               0x000000018552a330 _dispatch_main_queue_callback_4CF + 1000 (inline_internal.h:2421)
14  CoreFoundation                  0x0000000185a8a0cc __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12 (CFRunLoop.c:1793)
15  CoreFoundation                  0x0000000185a87cb8 __CFRunLoopRun + 1660 (CFRunLoop.c:3004)
16  CoreFoundation                  0x00000001859b78d8 CFRunLoopRunSpecific + 444 (CFRunLoop.c:3113)
17  GraphicsServices                0x00000001873be198 GSEventRunModal + 180 (GSEvent.c:2245)
18  UIKit                           0x000000018b9617c8 -[UIApplication _run] + 664 (UIApplication.m:2651)
19  UIKit                           0x000000018b95c534 UIApplicationMain + 208 (UIApplication.m:4088)
20  App                             0x000000010008c138 main + 152 (main.m:27)
21  libdyld.dylib                   0x00000001855585b8 start + 4

Thank you for any ideas.

Answer 1

You are saving _privateWriterContext in a block call of managedObjectContext . This is not allowed. The fact that it worked before is a "false positive".

Instead, you should always only use at the same context that creates the block.