[Python-Dev] Updates to PEP 471, the os.scandir() proposal (original) (raw)

Ben Hoyt benhoyt at gmail.com
Thu Jul 10 16:19:28 CEST 2014

DirEntry methods will remain free (no syscall) for directories and regular files. One extra syscall will be needed only for symlinks, which are more rare than other file types (for example, you wrote " Windows typically makes little use of symlinks"). The info we want for scandir is that of the link itself. That makes it easy to implement things like the "followlinks" flag of os.walk. The *far end* of the link isn't relevant at this level. The docs just need to be clear that DirEntry objects always match lstat(), never stat().

Yeah, I agree with this. It makes the function (and documentation and implementation) quite a lot simpler to understand.

scandir() is a lowish-level function which deals with the directory entries themselves, and mirrors both Windows FindNextFile and POSIX readdir() in that. If the user wants follow-links behaviour, they can easily call os.stat() themselves. If this is clearly documented that seems much simpler to me (and it also seems implicit to me in the fact that you're calling is_dir() on the entry).

Otherwise we might as well go down the route of -- the objects returned are just like pathlib.Path(), but with stat() and lstat() cached on first use.

-Ben

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