Core Data: error: Exception was caught during Core Data change processing

Question

I have been having this problem now for a few days and it's really frustrating.. I have been reviewing my code over and over again tried different thing and keeps having the same issue.. Which happens only 50% of the times not always. This makes it harder..

The Problem,

I am parsing the data from 3 csv files to my Core Data, which 2 of the files parsing always goes well but the middle/second file is where the crash always happens so, this will be address to that file and managedObjectContext class for this file.

Error Message

CoreData: error: Serious application error.   Exception was caught during Core Data change processing.  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.   -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null) 2014-09-12 11:27:06.115 AppName[210:3907] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFSet addObject:]: attempt to insert nil' 

So, in my FetchData class I try to address the problem in different ways.

• First, I changed my .csv file and insert N/A to all the fields/cells that were empty.
• Second, I'm doing a check in my FetchData class if this doesn't has any value, save N/A.
• Third, In my view controller where I'm firing the parsing the data, I have now separated three different properties for these 3 entities in my Core Data.

@property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;

@property (nonatomic, strong) NSManagedObjectContext *managedObjectContextGI;

@property (nonatomic, strong) NSManagedObjectContext *managedObjectContextVA;

It might be a bit crazy or whatever but I really need to fix this so, trying any possible solution or approach to this it's always good, I think.

ViewController to calling the functions to perform the parsing..

//at the beginning of my model #define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)  -(IBAction)myLoadingTask:(id)sender{         dispatch_async(kBgQueue, ^{             NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];             NSString *savedValue = @"";             if([[userDefaults stringForKey:@"dataFetched"] length] > 0){                                            savedValue = [userDefaults stringForKey:@"dataFetched"];            }             // if the csv files data hasn't been fetch it, then fetch it            if([savedValue length] == 0){                 FetchData *fd = [[FetchData alloc] initWithManagedContext:self.managedObjectContext];                 // fetching benefits data                [fd beginParser];                 FetchGIBillData *fdGI = [[FetchGIBillData alloc] initWithManagedContext:self.managedObjectContextGI];                 // fetching gi bill data                [fdGI beginParser];                 FetchVAPhones *fdVA = [[FetchVAPhones alloc] initWithManagedContext:self.managedObjectContextVA];                 // fetching va phones                [fdVA beginParser];                 NSString *valueToSave = @"saved";                [[NSUserDefaults standardUserDefaults] setObject:valueToSave forKey:@"dataFetched"];                [[NSUserDefaults standardUserDefaults] synchronize];             }         }); } 

This is my Core Data model functions and so on.. Which I have performed the check if it was empty save N/A and so on.. all my properties which are in my entity are strings

#define GIBILL_FILENAME @"gi_bill_data"  int numOfEntries; - (id)initWithManagedContext:(NSManagedObjectContext*)managedObjectContext {     self.managedObjectContext = managedObjectContext;     arrayOfRecords = [[NSMutableArray alloc] init];     numOfEntries=0;     return self; }   - (void) beginParser {     if (self.managedObjectContext == nil){         // Error: Must pass in NSManagedObjectContext         return;     }      NSString *filePath = [[NSBundle mainBundle] pathForResource:GIBILL_FILENAME ofType:@"csv"];     NSInputStream *stream = [NSInputStream inputStreamWithFileAtPath:filePath];     NSStringEncoding encoding = NSUTF8StringEncoding;//NSWindowsCP1250StringEncoding;      CHCSVParser *parser = [[CHCSVParser alloc] initWithInputStream:stream usedEncoding:&encoding delimiter:','];     parser.delegate = self;      [parser parse];      // uncomment to update data x amount of dates     //[self checkDateForRefreshCSV:parser];  } 

** This is where the saving happens!! *

#pragma mark - Data Add /**  * addRows  * @param parser: the CHCSV parser that will parse if required refresh  * @brief: add the row to ths managedObjectContent DB. All values saved.  */ - (void) addRows:(CHCSVParser *)parser {     int i = -1;     if ([arrayOfRecords count] == 0) return;     GIBill *data = [NSEntityDescription                       insertNewObjectForEntityForName:@"GIBill"                       inManagedObjectContext:self.managedObjectContext];      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.facility_code = [arrayOfRecords objectAtIndex:i];     else         data.facility_code = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.institution = [arrayOfRecords objectAtIndex:i];     else         data.institution = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.city = [arrayOfRecords objectAtIndex:i];     else         data.city = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.state = [arrayOfRecords objectAtIndex:i];     else         data.state = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.country = [arrayOfRecords objectAtIndex:i];     else         data.country = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.bah = [arrayOfRecords objectAtIndex:i];     else         data.bah = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.poe = [arrayOfRecords objectAtIndex:i];     else         data.poe = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.yr = [arrayOfRecords objectAtIndex:i];     else         data.yr = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.gibill = [arrayOfRecords objectAtIndex:i];     else         data.gibill = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 0)         data.cross = [arrayOfRecords objectAtIndex:i];     else         data.cross = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.grad_rate = [arrayOfRecords objectAtIndex:i];     else         data.grad_rate = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.grad_rate_rank = [arrayOfRecords objectAtIndex:i];     else         data.grad_rate_rank = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.default_rate = [arrayOfRecords objectAtIndex:i];     else         data.default_rate = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.avg_stu_loan_debt = [arrayOfRecords objectAtIndex:i];     else         data.avg_stu_loan_debt = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.avg_stu_loan_debt_rank = [arrayOfRecords objectAtIndex:i];     else         data.avg_stu_loan_debt_rank = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.indicator_group = [arrayOfRecords objectAtIndex:i];     else         data.indicator_group = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.salary = [arrayOfRecords objectAtIndex:i];     else         data.salary = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.zip = [arrayOfRecords objectAtIndex:i];     else         data.zip = @"N/A";      if([[arrayOfRecords objectAtIndex:++i] length] > 2)         data.ope = [arrayOfRecords objectAtIndex:i];     else         data.ope = @"N/A";      NSError *error;      [self.managedObjectContext save:&error];  } 

Well, I posted the most relevant code that I think of the issue. Please if something else is needed or more details about the problem let me know and I will provide it..

Thanks in advance!

Answer 1

The line below saved my day:

_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType]; 

You just have to set the concurrency type as Private. This way it can perform multiple operations on database concurrently on private queue's.