Weird bug - can access NSURLConnection & NSMutableData's description method, but not their ivars

Question

so I got class:
DataFetcher.h

#import <Foundation/Foundation.h>

@interface DataFetcher : NSObject 
{
    NSURLConnection *networkConnection;
    NSMutableData *recievedData;
    BOOL isFetchingFinished;
}

@property (nonatomic, retain) NSMutableData *recievedData;
@property (nonatomic, retain) NSURLConnection *networkConnection;

- (void)fetchDataWithRequest:(NSMutableURLRequest *)request;

DataFetcher.m:

#import "DataFetcher.h"

@implementation DataFetcher

@synthesize recievedData;
@synthesize networkConnection;

- (id)init
{
    self = [super init];
    if (self) {
        NSMutableData *data = [[NSMutableData alloc] initWithLength:0];
        self.recievedData = data;
        [data release];
    }

    return self;
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"Connection Error:%@\n Failure Reason:%@", [error localizedDescription], [error localizedFailureReason]);
    [networkConnection release];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [self.recievedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    [networkConnection release];
    NSLog(@"%@", self.recievedData.length);
    [self processData];
}

- (void)fetchDataWithRequest:(NSMutableURLRequest *)request
{
    NSURLConnection *aConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
    self.networkConnection = aConnection;
    [aConnection release];
    [self.networkConnection start];
    if( !self.networkConnection )
    {
        NSLog(@"Connection failed! recieved nil at alloc point");
    }
}

- (void)dealloc
{
    [super dealloc];
    [recievedData release];
}

@end

Normally it crashes on account of EXC_BAD_ACCESS ( NSZombie wont detect anything ). I noticed that if you switch on connectionDidFinishLoading the self.recievedData.length to just self.recievedData, it wont crash and looks like there is some data in there. the same thing I get for the self.networkConnection - if I just print self.networkConnection, its ok, but if I print self.networkConnection.retainCount ( for example, any ivar will work ) it will crash with the same signal.

I can't seem to grasp where the problem is, and I've been looking for it for quiet a while, And I will appreciate some help with this :)
Tnx!

Oh, and I call it with this code:
DataFetcher *fetcher = [[DataFetcher alloc] init];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"http://www.google.com"]]; [fetcher fetchDataWithRequest:request]; [fetcher release]; [request release];

Answer 1

NSLog(@"%@", self.recievedData.length);

Here %@ format specifier means that you're going to log objective-c object, while you actuall pass plain integer to it - that makes your app crash. Change your log to

 NSLog(@"%d", self.recievedData.length);