[Python-Dev] Issue 11406: adding os.scandir(), a directory iterator returning stat-like info (original) (raw)

Ben Hoyt benhoyt at gmail.com
Tue May 14 00:50:13 CEST 2013

OK, you got me! I'm now convinced that a property is a bad idea.

Thanks. :-)

I still like to annotate that the function may return a cached value. Perhaps lstat() could require an argument?

def lstat(self, cached): if not cached or self.lstat is None: self.lstat = os.lstat(...) return self.lstat

Hmm, I'm just not sure I like the API. Setting cached to True to me would imply it's only ever going to come from the cache (i.e., just return self._lstat). Also, isdir() etc have the same issue, so if you're going this route, their signatures would need this too.

The DirEntry instance is really a cached value in itself. ".name" is cached, ".dirent" is cached, and the methods return cached if they can. That's more or less the point of the object. But you have a fair point, and this would need to be explicit in the documentation.

-Ben

True. My isdir/isfile/islink implementations should catch any OSError from the lstat() and return False (like os.path.isdir etc do). But then calling code still doesn't need try/excepts around the isdir() calls. This is how os.walk() is implemented -- there's no extra error handling around the isdir() call. You could take the opportunity and take the 'file was deleted' case into account. I admit it has a very low priority. Please regard the case for bonus points only. ;) Sure. I'm primarily a Windows dev, so not too familiar with all the fancy stat* functions. But what you're saying makes sense. I'm glad to be of assistance! The feature is new (added in 3.3) and is available on most POSIX platforms. http://docs.python.org/3/library/os.html#dir-fd If you need any help or testing please feel free to ask me. I really like to get this feature into 3.4. Christian

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