NSFileManager -createFileAtPath因NSInvalidArgumentException而失败

Question

Maybe I've just missed something in the documentation, but I can't find anything that says this behavior should have changed in iOS 8.

My app sets the current working directory to the Documents directory, then tries to create a file there using NSFileManager -createFileAtPath . Prior to iOS 8 this works fine. On devices running iOS 8, I get the following on the call to -createFileAtPath:

 *** Terminating app due to uncaught exception 'NSInvalidArgumentException',
 reason: '*** -[NSFileManager fileSystemRepresentationWithPath:]: nil or empty path argument'

Here is a minimal code snippet that reproduces the problem:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = [paths objectAtIndex:0];
[[NSFileManager defaultManager] changeCurrentDirectoryPath:docsDir];
[[NSFileManager defaultManager] createFileAtPath:@"temp.dat" contents:nil attributes:nil];

Note the path argument on createFileAtPath is "temp.dat" - if I change it to "./temp.dat" , the call succeeds.

Am I doing something stupid and this was just "accidentally" working in prior iOS releases? Or did they intentionally change the behavior here? Or is this a bug in iOS 8? Other NSFileManager methods that take a path argument seem to be okay with just a filename (eg -removeItemAtPath:@"temp.dat" error:&err succeeds).

Edited to add:

This only happens on a physical device. In the simulator, the above call to createFileAtPath succeeds.

Answer 1

I opened a bug with Apple and they closed it as a duplicate. While that doesn't necessarily confirm that they consider it a bug, it at least confirms that I'm not the first to encounter this, and that the behavior did indeed change with iOS 8.

For now, the solution is to prepend ./ to the filename, or supply an absolute path.