gistfile1.m

- (NSPersistentStore *) MR_addSqliteStoreNamed:(id)storeFileName withOptions:(__autoreleasing NSDictionary *)options
{
    NSURL *url = [storeFileName isKindOfClass:[NSURL class]] ? storeFileName : [NSPersistentStore MR_urlForStoreName:storeFileName];
    NSError *error = nil;
    
    [self MR_createPathToStoreFileIfNeccessary:url];
    
//    NSPersistentStore *store = [self addPersistentStoreWithType:NSSQLiteStoreType
//                                                  configuration:nil
//                                                            URL:url
//                                                        options:options
//                                                          error:&error];

    NSPersistentStore *store = nil;
    error = [NSError errorWithDomain:NSCocoaErrorDomain code:256 userInfo:nil];

    if (!store && [MagicalRecord shouldDeleteStoreOnModelMismatch])
    {
        BOOL isMigrationError = [error code] == NSPersistentStoreIncompatibleVersionHashError || [error code] == NSMigrationMissingSourceModelError;
        if ([[error domain] isEqualToString:NSCocoaErrorDomain] && isMigrationError)
        {
            // Could not open the database, so... kill it!
            [[NSFileManager defaultManager] removeItemAtURL:url error:nil];

            MRLog(@"Removed incompatible model version: %@", [url lastPathComponent]);
            
            // Try one more time to create the store
            store = [self addPersistentStoreWithType:NSSQLiteStoreType
                                       configuration:nil
                                                 URL:url
                                             options:options
                                               error:&error];

            if (store)
            {
                // If we successfully added a store, remove the error that was initially created
                error = nil;
            }
        }
                
        [MagicalRecord handleErrors:error];
    }
    return store;
}