Why is executeFetchRequest:fetchRequest leaking memory?

Question

Instruments shows the following code leaks, if I comment out this code there is no leak.

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

    // Edit the entity name as appropriate.

    NSEntityDescription *entity = [NSEntityDescription entityForName:USER_CORE_DATA inManagedObjectContext:self.managedObjectContext];

    [fetchRequest setEntity:entity];

    NSPredicate *predicte = [NSPredicate predicateWithFormat:@"username == %@", [[User defaultManager] savedUsername]];
    [fetchRequest setPredicate:predicte];

    // set any predicates or sort descriptors, etc.

    // execute the request
    [self.managedObjectContext executeFetchRequest:fetchRequest onSuccess:^(NSArray *results) {

    } onFailure:^(NSError *error) {

        NSLog(@"Error fetching: %@", error);

    }];
    [fetchRequest release];

Specifically instruments says this line in the code above:

[self.managedObjectContext executeFetchRequest:fetchRequest onSuccess:^(NSArray *results)

It appears to be a leak with fetchRequest and/or the block. Any help will be appreciated, and thanks in advance.

for these complexity... i convert thiese to ARC. – Anoop Vaidya Jun 16 '13 at 06:33 — Anoop Vaidya, Jun 16 '13 at 06:33

score 0 · Answer 1 · answered Jun 16 '13 at 06:53

0

It appears executeFetchRequest:onSuccess:onFailure: is a function you have defined in NSManagedObjectContext category. Ensure the NSArray object instance that you are passing to the onSuccess block is autoreleased.

answered Jun 16 '13 at 06:53

Adithya

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That's not a function, it is a Block. – Anoop Vaidya Jun 16 '13 at 07:13
@AnoopVaidya C'mon.. executeFetchRequest:onSuccess:onFailure: is a function, the arguments passed to onSuccess and onFailure are blocks! – Adithya Jun 16 '13 at 07:48
'executeFetchRequest:onSuccess:onFailure:' is a function defined in StackMob's library, its not one that I can view. I can try releasing the NSArray myself to see if that changes anything. – Michael Wildermuth Jun 17 '13 at 05:02
When trying to release the NSArray results, I get an over release crash. – Michael Wildermuth Jun 17 '13 at 06:05
Ok. Then the array is autoreleased and that's fine. – Adithya Jun 17 '13 at 06:20
I have three leaks all pointing at the same function call in 3 different places. Kinda driving me crazy. – Michael Wildermuth Jun 17 '13 at 06:38
@MichaelWildermuth Go for ARC. – Adithya Jun 17 '13 at 08:07
ARC didn't not make the leak go away. I started a ticket with StackMob to see whats going on. – Michael Wildermuth Jun 18 '13 at 07:11

Michael Wildermuth · Accepted Answer · 2013-06-26T05:37:43.710

Actually it turned out that StackMob had a leak in their code, I downloaded there source and fixed it.

- (NSString *)primaryKeyField
{
    NSString *objectIdField = nil;

    // Search for schemanameId
    objectIdField = [[self SMSchema] stringByAppendingFormat:@"Id"];
    if ([[[self entity] propertiesByName] objectForKey:objectIdField] != nil) {
        return objectIdField;
    }

    objectIdField = nil;  // This line was missing and causing a leak

    // Search for schemaname_id
    objectIdField = [[self SMSchema] stringByAppendingFormat:@"_id"];
    if ([[[self entity] propertiesByName] objectForKey:objectIdField] != nil) {
        return objectIdField;
    }

    objectIdField = nil;  // This line was missing and causing a leak

    // Raise an exception and return nil
    [NSException raise:SMExceptionIncompatibleObject format:@"No Attribute found for `entity %@ which maps to the primary key on StackMob. The Attribute name should match one of the following formats: lowercasedEntityNameId or lowercasedEntityName_id.  If the managed object subclass for %@ inherits from SMUserManagedObject, meaning it is intended to define user objects, you may return either of the above formats or whatever lowercase string with optional underscores matches the primary key field on StackMob.", [[self entity] name], [[self entity] name]];`

Why is executeFetchRequest:fetchRequest leaking memory?

2 Answers2