Troubleshooting NSPersistentStoreCoordinator Issues in iOS Apps

Based on the provided code, I can see that there are several issues that could be causing the error:

persistentStoreCoordinator is not initialized properly.
The mainThreadManagedObjectContext and managedObjectContext_roster methods may return a null value.
There might be an issue with the database file name or its path.

Here are some steps to troubleshoot this issue:

Check if persistentStoreCoordinator is being initialized correctly by adding breakpoints or logging statements at the point of initialization (self.persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];).
Ensure that the database file name and its path are valid.
Verify if managedObjectContext_roster returns a non-null value by adding a null check: if (self.managedObjectContext_roster) { // ... }
If using an in-memory persistent store, ensure that the mainThreadManagedObjectContext is created correctly by checking its properties and initializing it with a valid concurrency type.

Here’s an updated version of your code:

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (!persistentStoreCoordinator)
    {
        NSManagedObjectModel *mom = [self managedObjectModel];
        if (mom == nil)
        {
            XMPPLogVerbose(@"%@: Creating persistentStoreCoordinator", [self class]);
            return nil;
        }

        XMPPLogVerbose(@"%@: Creating persistentStoreCoordinator", [self class]);

        persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:mom];

        if (databaseFileName)
        {
            // SQLite persistent store

            NSString *docsPath = [self persistentStoreDirectory];
            NSString *storePath = [docsPath stringByAppendingPathComponent:databaseFileName];
            if (storePath)
            {
                // If storePath is nil, then NSURL will throw an exception

                if(autoRemovePreviousDatabaseFile)
                {
                    if ([[NSFileManager defaultManager] fileExistsAtPath:storePath])
                    {
                        [[NSFileManager defaultManager] removeItemAtPath:storePath error:nil];
                    }
                }

                [self willCreatePersistentStoreWithPath:storePath options:storeOptions];

                NSError *error = nil;

                BOOL didAddPersistentStore = [self addPersistentStoreWithPath:storePath options:storeOptions error:&amp;error];

                if(autoRecreateDatabaseFile &amp;&amp; !didAddPersistentStore)
                {
                    [[NSFileManager defaultManager] removeItemAtPath:storePath error:NULL];

                    didAddPersistentStore = [self addPersistentStoreWithPath:storePath options:storeOptions error:&amp;error];
                }

                if (!didAddPersistentStore)
                {
                    XMPPLogWarn(@"%@: Did not add persistent store toCoordinator", [self class]);
                    return nil;
                }
            }
            else
            {
                XMPPLogWarn(@"%@: Error creating persistentStoreCoordinator - Nil persistentStoreDirectory",
                            [self class]);
                return nil;
            }
        }
    }

    return persistentStoreCoordinator;
}

- (NSManagedObjectContext *)managedObjectContext_roster
{
    if (!mainThreadManagedObjectContext)
    {
        mainThreadManagedObjectContext = [self mainThreadManagedObjectContext];
        XMPPLogVerbose(@"%@: Creating managedObjectContext_roster", [self class]);
        return nil;
    }

    return mainThreadManagedObjectContext;
}

Please make sure that persistentStoreDirectory and databaseFileName are correctly defined.

Last modified on 2024-02-29