What is the logic behind copying properties into a "fresh" variable for use in a method?

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The following code is from Apple's Core Data template, but I've seen similar code from many different developers:

- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
             // Replace this implementation with code to handle the error appropriately.
             // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        } 
    }
}

Why is there a new object created for the managedObjectContext? Why is self.managedObjectContext not sufficient. Personally, I would have used just that.

What is the logic behind copying a property into a fresh, local variable when you could simply use the property?

asked 1 min ago

Doug Smith

662