Yet another NSURLCache bug

NSURLCacheCrash.m

/*
    This crashes (usually after the first log, but not 100% reliable) on at least iOS 4.3, 5.0 and 5.1
    (lldb) bt
    * thread #1: tid = 0x1c03, 0x36d60e58 CoreFoundation`CFRetain + 20, stop reason = EXC_BAD_ACCESS (code=1, address=0xe0000000)
        frame #0: 0x36d60e58 CoreFoundation`CFRetain + 20
        frame #1: 0x33927248 CFNetwork`__CFURLCache::CopyResponseForRequest(_CFURLRequest const*, bool) + 116
        frame #2: 0x339271cc CFNetwork`_ZL34__CFURLCacheCopyResponseForRequestPK11_CFURLCachePK13_CFURLRequestb + 48
        frame #3: 0x33927e5c CFNetwork`CFURLCacheCopyResponseForRequest + 24
        frame #4: 0x32a7487e Foundation`-[NSURLCache cachedResponseForRequest:] + 66
        frame #5: 0x0006963c NSURLCacheCrash`main + 504 at main.m:28
*/

#import <Foundation/Foundation.h>

int main(int argc, char *argv[])
{
	@autoreleasepool
	{
		NSURLCache *sharedURLCache = [NSURLCache sharedURLCache];
		NSURL *dummyURL = [NSURL URLWithString:@"nsurlcache:ready"];
		NSURLResponse *dummyResponse = [[NSURLResponse alloc] initWithURL:dummyURL MIMEType:nil expectedContentLength:0 textEncodingName:nil];
		NSCachedURLResponse *dummyCachedResponse = [[NSCachedURLResponse alloc] initWithResponse:dummyResponse data:[NSData data]];
		NSURLRequest *dummyRequest = [NSURLRequest requestWithURL:dummyURL];
		[sharedURLCache storeCachedResponse:dummyCachedResponse forRequest:dummyRequest];
		NSCachedURLResponse *cachedResponse = nil;
		while (!cachedResponse)
		{
			cachedResponse = [sharedURLCache cachedResponseForRequest:dummyRequest];
			NSLog(@"cachedResponse: %@", cachedResponse);
		}
		
		return EXIT_SUCCESS;
	}
}

I ran into same situation, the sharedURLCache was released somehow, it will raise a zombie message if you test it in instruments, not quite sure it's a bug or my fault, but I couldn't make it right.

Looks like this bug was fixed in iOS 6.0 and later, I've just tested it.