核心数据:尝试删除时的“NSObjectInaccessibleException”。

Question

核心数据允许我保存，但是当我试图删除对象时，我得到了以下错误：

*** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0xa6b7e00 <x-coredata://8A687ECB-03F8-47C0-8470-087B9CF032B1-2801-00000A8C9A09CDB7/Notification/p2774005D-4B49-4378-A109-949F15D37032>'的

[self.managedObjectContext executeFetchRequest:allFetchRequest onSuccess:^(NSArray *results) {
                NSLog(@"Fetch for Objects with origial_id");
                if (results.count>0)
                {
                    NSLog(@"original_id =  %@", dlPlanDate.original_id);
                    NSLog(@"Results Recieved %i", results.count);
                    for (PlanDate *pd in results)
                    {
                        PlanDateResolved *pdResolved = [NSEntityDescription insertNewObjectForEntityForName:@"PlanDateResolved" inManagedObjectContext:self.managedObjectContext];
                        NSArray *keys = [[[pd entity] attributesByName] allKeys];
                        NSDictionary *dict= [pd dictionaryWithValuesForKeys:keys];
                        [pdResolved setValuesForKeysWithDictionary:dict];
                        [pdResolved setValue:[pd plandate_id] forKey:[pdResolved primaryKeyField]];
                        pdResolved.senderUser = pd.senderUser;
                        pdResolved.objectCreator = pd.objectCreator;
                        pdResolved.users = pd.users;
                        NSLog(@"pd.planDateID %@", pd.plandate_id);
                        [self.managedObjectContext saveOnSuccess:^{

                        NSLog(@"Saving Each Object in the Array  to PlanDateResolved with Original ID");
                            [self.managedObjectContext deleteObject:pd];
                            [self.managedObjectContext saveOnSuccess:^{
                                NSLog(@"Deleted the pd Object object!");
                            } onFailure:^(NSError *error) {
                                NSLog(@"There was an error Deleting pd Object %@", error);
                            }];
                        } onFailure:^(NSError *error) {
                        }];
                    }
                }
            } onFailure:^(NSError *error) {
                NSLog(@"Error fetching: %@", error);
            }];
        }

日志：

2013-10-11 11:53:11.175 ST[2801:c07] Fetch for Objects with origial_id
2013-10-11 11:53:11.175 ST[2801:c07] original_id =  CFADD5A7-C9E8-48B3-91B2-56FDBC0F9BAB
2013-10-11 11:53:11.175 ST[2801:c07] Results Recieved 3
2013-10-11 11:53:11.180 ST[2801:c07] pd.planDateID CFADD5A7-C9E8-48B3-91B2-56FDBC0F9BAB
2013-10-11 11:53:11.182 ST[2801:c07] pd.planDateID 5917071A-8CFD-4C7C-A60F-A76FA4814429
2013-10-11 11:53:11.183 ST[2801:c07] pd.planDateID 1998BB90-D6FC-4226-977C-3414C4A57078
2013-10-11 11:53:11.913 ST[2801:c07] You updated the Accepted object!
2013-10-11 11:53:11.913 ST[2801:c07] Saving Each Object in the Array  to PlanDateResolved with Original ID
2013-10-11 11:53:11.913 ST[2801:c07] Saving Each Object in the Array  to PlanDateResolved with Original ID
2013-10-11 11:53:12.155 ST[2801:c07] Saving Each Object in the Array  to PlanDateResolved with Original ID
2013-10-11 11:53:35.482 ST[2801:c07] *** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0xa6b7e00 <x-coredata://8A687ECB-03F8-47C0-8470-087B9CF032B1-2801-00000A8C9A09CDB7/Notification/p2774005D-4B49-4378-A109-949F15D37032>''
*** First throw call stack:
(0x24e7012 0x1cfae7e 0x1a20a48 0x1a515e8 0x1ac2879 0x1a59627 0x1a59271 0x1ace025 0x1a53cc1 0x1e7f014 0x1e6ed5f 0x1e6eaa3 0x1a53c8b 0x1a53aee 0x1a30eac 0x1ab0c1 0x1a5398f 0x1e7f014 0x1e6f7d5 0x248daf5 0x248cf44 0x248ce1b 0x24027e3 0x2402668 0x92effc 0x418d 0x25c5)
libc++abi.dylib: terminate called throwing an exception

Answer 1

当托管对象是不可访问的时，这意味着Core无法在持久存储文件中找到该对象。这种情况可能发生的原因有几个。

我不知道executeFetchRequest:onSuccess:和saveOnSuccess:是从哪里来的，但是假设它们做了它们的方法名称所暗示的(而且并不是可怕的错误)，那么在上面的代码中没有明显的原因会发生这种情况。所以这是你在其他地方工作的副作用。

最有可能的情况是:您还会在其他地方删除这些对象，而这个删除会在执行fetch之后发生，但在代码崩溃之前发生。因此，当上面的代码试图删除它们时，它们已经消失了。看来，您使用的神秘核心数据方法是异步运行的(基于在到达崩溃点之前多次打印pd.planDateID的事实)，因此可以在同一个线程上运行，也可以在另一个线程上运行。

所有这些假设您的日志语句实际上来自您发布的代码。这在一定程度上是有疑问的，因为日志中包含一条消息，上面写着“您更新了已接受的对象！”，这条消息在代码中没有出现。

Answer 2

我同意汤姆·哈林顿关于根本问题的解释。此外，还很高兴知道，自从iOS 9以来，行为已经改变了。在NSObjectInaccessibleException 9上没有引发iOS，但会出现CoreData警告，如下所示：

CoreData: warning: An NSManagedObjectContext delegate overrode fault
handling behavior to silently delete the object with ID '0xd0000000025c0006
<x-coredata://336D9F02-727B-42C5-AEDD-8007D4AB521D/Film/p151>' and substitute 
nil/0 for all property values instead of throwing.
2015-09-10 15:27:09.799 PROJECTX[2141:818058] CoreData: error: Mutating a
managed object 0xd0000000025c0006 <x-coredata://336D9F02-727B-42C5-AEDD-
8007D4AB521D/Bla/p151> (0x12812bea0) after it has been removed from its 
context.

这不会导致崩溃，而是一个模棱两可的应用行为。

Answer 3

如果您试图在错误的NSManagedObject中访问NSManagedObjectContext，通常会发生这种情况。如果使用UI线程中的托管对象(直接显示数据或在主线程上进行操作)，则需要使用NSMainQueueConcurrencyType并发。

另外，如果您在后台线程上使用对象，那么它应该是带有NSPrivateQueueConcurrencyType并发的智利上下文。