Why does static NSString leak?

I have the following code to retrieve file paths on my iOS Apps: static const NSString * fullPathFromRelativePath(NSString *relPath) { // do not convert a path starting with '/' if(([relPath length] > 0) && ([relPath characterAtIndex:0] == '/')) return relPath; NSMutableArray *imagePathComponents = [NSMutableArray arrayWithArray:[relPath pathComponents]]; NSString *file = [imagePathComponents last

[rna]

performSelectorInBackgroundとか使う場合は明示的に@autoreleasepool {}しないとリークするという話。