[Python-ideas] Implementation of shutil.move (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Fri Aug 12 14:29:21 CEST 2011

On Fri, 12 Aug 2011 13:59:22 +0200 David Townshend <aquavitae69 at gmail.com> wrote:

The shutil.move function uses os.rename to move files on the same file system. On unix, this function will overwrite an existing destination, so the obvious approach is

if not os.path.exists(dst): shutil.move(src, dst) But this could result in race conditions if dst is created after os.path.exists and before shutil.move. From my research, it seems that this is a limitation in the unix c library, but it should be possible to avoid it through a workaround (pieced together from http://bytes.com/topic/python/answers/555794-safely-renaming-file-without-overwriting). This involves some fairly low-level work, so I propose adding a new move2 function to shutil, which raises an error if dst exists and locking it if it doesn't:

This is a reasonable request (although it could also be an optional argument to shutil.move() rather than a separate function). Could you open an issue with your proposal on http://bugs.python.org ? You are also welcome to submit a patch in the issue; please see http://docs.python.org/devguide/

Regards

Antoine.

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