Question

Why would the following implementation of the Dictionary cause a memory leak? See the screenshot below as well. Practically all of the leaks there are from this method.

- (void) setLocation:(NSString *) location:(NSString *) turnPage {
    NSLog(@"Start setLocation");
    //---get the path to the property list file---
    NSString *localPlistFileNameConf = [[self documentsPath] stringByAppendingPathComponent:@"Config.plist"];
    NSMutableDictionary *copyOfDict;
    //---if the property list file can be found---
    if ([[NSFileManager defaultManager] fileExistsAtPath:localPlistFileNameConf]) {
        //---load the content of the property list file into a NSDictionary object---
        NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:localPlistFileNameConf];
        //---make a mutable copy of the dictionary object---
        copyOfDict = [dict mutableCopy];
        [dict release];
    }
    else {
        //---load the property list from the Resources folder---
        NSString *pListPath = [[NSBundle mainBundle] pathForResource:@"Config" ofType:@"plist"];
        NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:pListPath];
        //---make a mutable copy of the dictionary object---
        copyOfDict = [dict mutableCopy];
        [dict release];
    }
    location = [self checkLocationValidity:location:turnPage];
    [copyOfDict setValue:location forKey:@"Location"];
    [self writeConfigToFile:copyOfDict];
    NSLog(@"End setLocation");
}

Answer 1

You’re not releasing copyOfDict anywhere. You own any object created with a method that starts with copy, so you need to release those objects. It’s probably misreporting the source as the original dictionary due to a bit of trickery in the NSDictionary class cluster for efficiency reasons. Try running analyse over your code, it should point these things out to you.