#property scope issues and memory problems - iphone

Question

I am having a crash I do not understand. I am downloading a couple files from a remote server, and when a file has finished downloading, I am attempting to retrieve an object that was attached to the request object.
Tia for any help!
S.
Main Class
for (TrainingEntry* _entry in objects) {
HTTPRequest * request = [HTTPRequest requestWithURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#/%#", [[ConfigLoader config] objectForKey:#"Server"], _entry.url]]];
[request setDownloadDestinationPath:[NSString stringWithFormat:#"%#/%#", documentsDirectoryPath, _entry.filename]];
[request setEntry:_entry];
[request setRaw:_entry.title];
TrainingEntry * test = (TrainingEntry*)[request _entry];
NSLog(#"title: %#", [test title]); //<= This works
NSLog(#"filename: %#", [test filename]); //<= This works
[[self networkQueue] addOperation:request];
}
// Start Queue
[[self networkQueue] go];
...
- (void)requestFinished:(HTTPRequest *)request {
if ([[self networkQueue] requestsCount] == 0) {
[self setNetworkQueue:nil];
}
NSLog(#"req: %#", [request raw]);
NSLog(#"title: %#", [[request entry] title]); // <= This works
NSLog(#"filename: %#", [[request entry] filename]); // <= This crashes
}
HTTPRequest Object
#interface HTTPRequest : ASIHTTPRequest {
}
#property (nonatomic, retain) TrainingEntry * entry;
#property (nonatomic, retain) NSString * raw;
#end
TrainingEntry Class
#interface TrainingEntry : NSObject {
NSString * title;
NSString * filename;
}
#property (nonatomic, retain) NSString * title;
#property (nonatomic, retain) NSString * filename;

Answer 1

Something that may be giving you trouble is not having copy in your property declaration. You should consider using copy for all objects that conform to the NSCopying protocol specification, especially NSString and other collection classes.
In the past, changing retain to copy for an NSString property solved a similar issue for me.
edit: some research
This post may help clarify why you should use copy over retain for immutable objects.

Answer 2

When a crash occurs, there will be a backtrace.
Post it.
Either your program will break in the debugger, and the call stack will be in the debugger UI (or you can type 'bt
With that, the cause of the crash is often quite obvious. Without that, we are left to critique the code.
If this crashes:
NSLog(#"filename: %#", [[request entry] filename]); // <= This crashes
It is either because request has been over-released and is no longer viable or because filename is returning a garbage object. Given that request worked previously, it is likely that filename has been over-released.
Where do you set filename?