Why might changes be populated from one NSManagedObjectContext to another without an explicit merge?
- by Mike Laurence
I'm working on an object import feature that utilizes multiple threads/NSManagedObjectContexts, using http://www.mac-developer-network.com/columns/coredata/may2009/ as my guide (note that I am developing for iPhone).
For some reason, when I save one of my contexts the other is immediately updated with the changes, even though I have commented out my calls to mergeChangesFromContextDidSaveNotification. Are there any reasons the contexts might be merging into one another without an explicit call?
Here a log of what's going on:
// 1.) Main context is saved with "Peter Gabriel"
// 2.) Test context is created, begins with same contents as main context
// 3.) Main context is inserted with "Spoon"
// 4.) Test context is inserted with "Phoenix"
// Contents at this point:
CoreTest[4341:903] Artists in main context: (
"Peter Gabriel",
"Spoon"
)
CoreTest[4341:903] Artists in test context: (
"Peter Gabriel",
"Phoenix"
)
// 5.) testContext is saved
// New contents of contexts:
CoreTest[4341:903] Artists in main context: (
"Peter Gabriel",
"Phoenix",
"Spoon"
)
CoreTest[4341:903] Artists in test context: (
"Peter Gabriel",
"Phoenix"
)
As you can see, the test context is saved midway through, and the main context suddenly has the new objects from the test context, even though I haven't performed the whole NSManagedObjectContextDidSaveNotification/mergeChangesFromContext combo.
My understanding is that no changes will ever be merged unless done so explicitly... does anyone know what's going on here?
