我已经找到窃听器了。它发生在willChangeValueForKey:withSetMutation:usingObjects:中。

这个呼叫会触发一连串的通知，可能很难追踪，当然，一个回复者的变化可能会影响到另一个，我怀疑这就是为什么苹果什么都没做的原因。

然而，这在Set中是可以的，只有OrderedSet上的Set操作会发生故障。这意味着只有四个方法需要修改。因此，我所做的只是将Set操作转换为等效的Array操作。这些工作非常完美，开销最小(但必要)。

On a critical level, this solution does suffer from one critical flaw; if you are adding objects and one of the objects already exists, then it is either not added or moved to the back of the ordered list (I don't know which). In either case, the expected ordered index of the object by the time we arrive at didChange is different from what was anticipated. This may break some people's apps, but it doesn't affect mine, since I am only ever adding new objects or I confirm their final locations before I add them.

- (void)addChildrenObject:(BAFinancialItem *)value {
    if ([self.children containsObject:value]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:self.children.count];
    [self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] addObject:value];
    [self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)removeChildrenObject:(BAFinancialItem *)value {
    if (![self.children containsObject:value]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:[self.children indexOfObject:value]];
    [self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] removeObject:value];
    [self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)addChildren:(NSOrderedSet *)values {
    if ([values isSubsetOfOrderedSet:self.children]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)];
    [self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] unionOrderedSet:values];
    [self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)removeChildren:(NSOrderedSet *)values {
    if (![self.children intersectsOrderedSet:values]) {
        return;
    }
    NSIndexSet * indexSet = [self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
        return [values containsObject:obj];
    }];
    [self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] minusOrderedSet:values];
    [self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}

当然，还有一个更简单的解决方案。内容如下;

- (void)addChildrenObject:(BAFinancialItem *)value {
    if ([self.children containsObject:value]) {
        return;
    }
    [self insertObject:value inChildrenAtIndex:self.children.count];
}

- (void)removeChildrenObject:(BAFinancialItem *)value {
    if (![self.children containsObject:value]) {
        return;
    }
    [self removeObjectFromChildrenAtIndex:[self.children indexOfObject:value]];
}

- (void)addChildren:(NSOrderedSet *)values {
    if ([values isSubsetOfOrderedSet:self.children]) {
        return;
    }
    [self insertChildren:values atIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)]];
}

- (void)removeChildren:(NSOrderedSet *)values {
    if (![self.children intersectsOrderedSet:values]) {
        return;
    }
    [self removeChildrenAtIndexes:[self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
        return [values containsObject:obj];
    }]];
}

我认为大家都忽略了真正的问题。它不是在访问器方法中，而是在NSOrderedSet不是NSSet的子类这一事实中。所以当-interSectsSet:以有序集作为参数调用时，它会失败。

NSOrderedSet* setA = [NSOrderedSet orderedSetWithObjects:@"A",@"B",@"C",nil];
NSSet* setB = [NSSet setWithObjects:@"C",@"D", nil];

 [setB intersectsSet:setA];

***错误-[NSSet intersectsSet:]: set参数不是NSSet

修复方法似乎是更改set操作符的实现，以便它们透明地处理类型。没有理由-intersectsSet:既适用于有序集合也适用于无序集合。

在更改通知中发生异常。大概是在处理逆关系的代码中。因为只有当我设置一个反比关系时才会发生。

下面的方法对我很有效

@implementation MF_NSOrderedSetFixes

+ (void) fixSetMethods
{
    NSArray* classes = [NSArray arrayWithObjects:@"NSSet", @"NSMutableSet", @"NSOrderedSet", @"NSMutableOrderedSet",nil];

    [classes enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSString* name = obj;
        Class aClass = objc_lookUpClass([name UTF8String]);
        [MF_NSOrderedSetFixes fixMethodWithSetArgument:@selector(intersectsSet:) forClass:aClass];
        [MF_NSOrderedSetFixes fixMethodWithSetArgument:@selector(isSubsetOfSet:) forClass:aClass];
    }];
}

typedef BOOL (*BoolNSetIMP)(id _s,SEL sel, NSSet*);

/*
    Works for all methods of type - (BOOL) method:(NSSet*) aSet
*/
+ (void) fixMethodWithSetArgument:(SEL) aSel forClass:(Class) aClass 
{
    /* Check that class actually implements method first */
    /* can't use get_classInstanceMethod() since it checks superclass */
    unsigned int count,i;
    Method method = NULL;
    Method* methods = class_copyMethodList(aClass, &count);
    if(methods) {
        for(i=0;i<count;i++) {
            if(method_getName(methods[i])==aSel) {
                method = methods[i];
            }
        }
        free(methods);
    }
    if(!method) {
        return;
    }

   // Get old implementation
   BoolNSetIMP originalImp  = (BoolNSetIMP) method_getImplementation(method);
   IMP newImp = imp_implementationWithBlock(^BOOL(NSSet *_s, NSSet *otherSet) {
        if([otherSet isKindOfClass:[NSOrderedSet class]]) {
            otherSet = [(NSOrderedSet*)otherSet set];
        }
        // Call original implementation
        return originalImp(_s,aSel,otherSet);
    });
    method_setImplementation(method, newImp);
}
@end

收到同样的错误，@LeeIII解决方案为我工作(谢谢!)。我建议稍微修改一下:

使用objective-c类别存储新方法(所以我们不会失去我们的方法，如果Item再次生成) 检查我们是否已经有了可变集合

Item+category.m的内容:

#import "Item+category.h"

@implementation Item (category)

- (void)addSubitemsObject:(SubItem *)value {
    if ([self.subitems isKindOfClass:[NSMutableOrderedSet class]]) {
        [(NSMutableOrderedSet *)self.subitems addObject:value];
    } else {
        NSMutableOrderedSet* tempSet = [NSMutableOrderedSet orderedSetWithOrderedSet:self.subitems];
        [tempSet addObject:value];
        self.subitems = tempSet;
    }
}

@end

苹果文档To Many Relations说:你应该访问代理可变集或有序集使用

NSMutableOrderedSet * set = [managedObject mutableOrderedSetValueForKey:@"toManyRelation"];

修改此集合将添加或删除与托管对象的关系。使用[]或访问器访问可变有序集。符号是错误的，会失败。

我通过谷歌错误信息找到了这个问题，只是想指出我以一种稍微不同的方式(不是使用有序集)遇到了这个错误。这并不完全是对给定问题的答案，但我把它贴在这里，以防它对其他在搜索时偶然发现这个问题的人有帮助。

我正在添加一个新的模型版本，并向现有模型添加了一些关系，并在头文件中自己定义了add*Object方法。当我尝试调用它们时，我得到了上面的错误。

在检查了我的模型之后，我意识到我愚蠢地忘记了勾选“to - many Relationship”复选框。

所以如果你遇到这种情况，你没有使用有序集，仔细检查你的模型。

相反，我建议使用NSObject中的访问器来访问关系的NSMutableOrderedSet。

- (void)addSubitemsObject:(SubItem *)value {
      NSMutableOrderedSet* tempSet = [self mutableOrderedSetValueForKey:@"subitems"];
      [tempSet addObject:value];
 }

例如，iOS v5.0的核心数据发布说明参考了这一点。

在一个简短的测试中，它在我的应用程序中工作。