CoreData NSManagedObject being corrupted - ios

Question

I have a controller that is the root of a workflow. If there is no data object for the workflow, then I create a new one, and if there is, I use the existing one. I have a property for the model object (an NSManagedObject)
#property (nonatomic, retain) Round *currentRound;
and I call the following whenever the corresponding view is shown
self.currentRound = [self.service findActiveRound];
if (!self.currentRound) {
NSLog((#"configure for new round"));
self.currentRound = [self.service createNewRound];
...
} else {
NSLog(#"configure for continue");
// bad data here
}
The problem is at the place marked in the above, sometimes the data object is corrupted. In the parts I didn't show I set the values on some text fields to represent the values in the model. Sometimes its ok, but eventually the properties on the model object are empty and things break
In the debugger, the reference to the round doesn't appear to change, but NSLogging the relevant properties shows them nullified. debugging seems to delay the onset of the corruption.
I am aware I am not saving the context...should that matter? And if so, how come it doesn't always fail the first time I come back to this controller?
My findActiveRound message is nothing special, but in case it matters
-(Round *) findActiveRound
{
NSLog(#"Create Active Round");
NSFetchRequest *request = [[NSFetchRequest alloc]init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Round" inManagedObjectContext:context];
[request setEntity:entity];
NSPredicate *pred = [NSPredicate predicateWithFormat:#"isComplete == %#", [NSNumber numberWithBool:NO]];
[request setPredicate:pred];
NSError *error = nil;
NSArray *results = [context executeFetchRequest:request error:&error];
if ([results count] == 0) {
return nil;
} else {
return [results objectAtIndex:0];
}
}
Many thanx.
EDIT FOR RESPONSE
By corrupted I mean when I try to get some simple string properties off the model object, I get nil values. So In the code above (where I think I have a round) I do stuff like
self.roundName.text = self.currentRound.venue;
self.teeSelection.text = self.currentRound.tees;
and don't see the data I entered. Since it only fails sometimes, but always fails eventually, I will see the data I entered for a while before its gone.
I'm pretty sure the context is the same. My service is a singleton and created like so
#implementation HscService
+(id) getInstance
{
static HscService *singleton = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
singleton = [[self alloc] init];
});
return singleton;
}
-(id) init
{
if (self = [super init]) {
model = [NSManagedObjectModel mergedModelFromBundles:nil];
NSPersistentStoreCoordinator *psc = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:model];
NSString *path = [self itemArchivePath];
NSURL *storeUrl = [NSURL fileURLWithPath:path];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES],
NSMigratePersistentStoresAutomaticallyOption,
[NSNumber numberWithBool:YES],
NSInferMappingModelAutomaticallyOption, nil];
NSError *error = nil;
if (![psc addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) {
[NSException raise:#"Open failed" format: #"Reason: %#", [error localizedDescription]];
}
context = [[NSManagedObjectContext alloc] init];
[context setPersistentStoreCoordinator:psc];
[context setUndoManager:nil];
}
return self;
}
-(NSString *) itemArchivePath
{
NSArray *docDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *dir = [docDirectories objectAtIndex:0];
return [dir stringByAppendingPathComponent:#"hsc1.data"];
}
and in every controller I get the singleton to perform operations. I plan on defining a delegate around round operations, and implementing it in my AppDelegate, so I'm only getting the service once in the app, but don't think that should matter for now....

Answer 1

Are you sure the data is actually corrupted? Managed object contexts are highly efficient, and it's normal to fault in the debugger. From the docs:
"Faulting is a mechanism Core Data employs to reduce your
application’s memory usage..."
See http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CoreData/Articles/cdFaultingUniquing.html
If the data is actually missing and cannot be accessed by other methods, make sure you're using the same Managed Object Context to access the data. If the data has not been committed to the data store, it will not "sync" between MOCs.