managedObjectContext save fails with error being null

What would cause an error to come back null, this is what I have

    + (BOOL)saveContext:(NSManagedObjectContext *)context开发者_开发技巧
    {
      NSError *error = nil;
      if (![context save:&error]) 
      {
        DLog(@"ERROR %@, %@", error, [error userInfo]);
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorry"

                                                        message:@"Error Saving the Data" 
                                                       delegate:nil 
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];

        [alert show];
        [alert release];

        return NO;
      }
    return YES;
    }

The above method is a class method, I am not sure why the error does not have any information.

This method is called like this

[HSCoreDataUtility saveContext:self.managedObjectContext];

when a modalViewController is closing and returning to the NavigationController, so I need the context to be saved, but it throughs an error, now I think I have an idea as to the cause of it not being saved, but shouldn't the error give me a clue? but the log just says "ERROR (null), (null)"

any thoughts

I lived your pain and end up surviving. ;)

After long debugging time I realized in custom object validation method, in some cases I was returning NO and not initializing an error.

If you have this problem check validation object methods. That probably was your problem as well.

Only way I can see that situation happening is if you are passing in a nil context. I would put a logic bomb at the top of that class method to guard against that.

Well, actually, I wouldn't create a class method for this small amount of code; but the point still stands. Check for a nil context.

This is a really old thread, but hopefully my response helps someone who finds this on Google like I did. I was running into this same problem and none of these answers were my problem; it turns out I made the very boneheaded, silly mistake of not deleting/reinstalling the app when I changed the data model, so the save was failing without an error. Check to make sure you don't do the same thing! :)

Uhm, I'm not sure %@ will cause the error to go verbose. [error localizedDescription] ?

I happened to meet this problem, and after long time debug I found it's because of a duplicate declaration of the NSError* error, may you had another NSError* error in the outer scope, like:

NSError* error = nil;

// some code

if (!error)
{
    NSError* error = nil;

    // your code
}

Then the error will be nil although in fact there is an exception.