EXC_BAD_INSTRUCTION with URLConnection initWithRequest

Question

I have a weird error that I cannot seem to find any documentation or posts for. When I try to connect to my web service (changed URL for privacy) using the standard textbook method, I receive EXC_BAD_INSTRUCTION or EXC_BAD_ACCESS on [NSURLConnection initWithRequest].

The weirdest thing is that on occasion I can step over the offending line without any exception, but 9 times out of 10 it causes this error. Any suggestions?

- (void)viewDidLoad {
    NSURL *url = [NSURL URLWithString:@"http://heres/where/my/webservice/url/is/"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:30.0];

    // cancel any old connection
    if(connection) {
        [connection cancel];
        [connection release];
    }

    // create new connection and begin loading data
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    if(connection) {
        // if the connection was created correctly, release old data (if any), and alloc new
        [data release];
        data = [[NSMutableData data] retain];
    }

    [url release];
    [request release];
}

Any help or suggestions or RTFMs will be much appreciated!

Answer 1

You are releasing autoreleased objects:

NSURL *url = [NSURL URLWithString:@"…"];
NSURLRequest *request = [NSURLRequest requestWithURL:url …];
// …
[url release];
[request release];

I think that Clang should be able to catch these, see Build → Build and Analyze (Cmd-Shift-A). Clang is your friend, get used to it.

Answer 2

EXC_BAD_ACCESS means you are trying to release an object that has alreay been released. As zoul says, the url and request methods you use are autoreleasing methods so you shouldn't manually release them at the end of your code.

What you should do is accept his answer... because he's right.