coredata not working on xcode 4.3? - iphone

Question

just wondering if someone else came across this.
I got this piece of code that used to work brilliant in previous xcode versions.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator != nil) {
return persistentStoreCoordinator;
}
NSString *storePath = [[self applicationDocumentsDirectory] stringByAppendingPathComponent:#"mydb.sqlite"];
/*
Set up the store.
For the sake of illustration, provide a pre-populated default store.
*/
NSFileManager *fileManager = [NSFileManager defaultManager];
// If the expected store doesn't exist, copy the default store.
if (![fileManager fileExistsAtPath:storePath]) {
NSString *defaultStorePath = [[NSBundle mainBundle] pathForResource:#"mydb" ofType:#"sqlite"];
if (defaultStorePath) {
[fileManager copyItemAtPath:defaultStorePath toPath:storePath error:NULL];
}
}
NSURL *storeUrl = [NSURL fileURLWithPath:storePath];
[self addSkipBackupAttributeToItemAtURL:storeUrl];
NSError *error;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];
if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&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. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
Typical reasons for an error here include:
* The persistent store is not accessible
* The schema for the persistent store is incompatible with current managed object model
Check the error message to determine what the actual problem was.
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return persistentStoreCoordinator;
}
I would expect the following from this:
an empty "mydb" to be created from scratch if there is no "mydb.sqlite" in my bundle.
if a "mydb.sqlite" exists in my main bundle then i would expect it to be copied in the specified diretory.
if the "mydb.sqlite" is not compatible with my xcdatamodel the app must crash.
however this works only with already created db's previously.
If for example i try to put a random db named "mydb.sqlite" to my bundle and delete the original one then,
the app doesnt crash!!! a blank db is created and the new db is ignored.
This is completely wrong as it goes against my code.
In addition if I add back the original db nothing happens and the app just creates a blank db.
(and yes I do clean my project, delete the sim app, and even delete the build folder before any change occurs!)
any ideas??

Answer 1

There is a difference between your code and your expectation as you've stated it.
Here is your expectation:
an empty "mydb" to be created from scratch if there is no "mydb.sqlite" in my bundle.
if a "mydb.sqlite" exists in my main bundle then i would expect it to be copied in the specified directory.
if the "mydb.sqlite" is not compatible with my xcdatamodel the app must crash.
Here is what your code does:
Look for mydb.sqlite in the Documents directory
If mydb.sqlite does not exist, copy it from the main bundle (if it exists in the main bundle)
Create a new persistent store at ~/Documents/mydb.sqlite
The main problem I think you're experiencing is because of Step 3. addPersistentStoreWithType:... creates a new store at the URL provided. You instead need to requery the existence of the file (to check that there is now a file existing which may have been copied from the MainBundle) and if it exists, then use [persistentStoreCoordinator persistentStoreForURL:storeURL] instead of creating a new persistent store.
Once you have fixed this, the other problems should be more easily traceable. I suggest adding many more NSLog's in to your code, so you can see whether the code is following the execution path you expect. E.g. log each new object you create so you can easily see if any of them are nil. When you copy your bundle db, add an NSError pointer rather than NULL, and then if the error is non-nil, log it.

Answer 2

the answer to the question/ observation is simple.
downgrade to 4.2.1
I have restored my xcode to 4.2.1 (thank God for Time Machine) and now ALL is as expected.
I will file a bug report to Apple later on today.

Answer 3

Check that your default db is actually being included in the bundle - i.e. it is checked as included in the project, and is in the copy files build phase. I rearranged a project and an SQLite file, whilst bring copied into the project structure, was not included in my project - this would cause the behaviour you are seeing.