As of Python 3.2, os.makedirs() takes exist_ok as a keyword argument. If set to true, the function does not raise an error if the directory already exists. This makes the function's behavior similar to mkdir -p on the UNIX commandline. (See https://docs.python.org/3/library/os.html#os.makedirs)

However, this functionality is missing in Python's new pathlib. In fact, the documentation for Path.mkdir() even mentions that if parent=True is passed, then it should behave like mkdir -p. This is accurate in that it indeed recursively makes any parent directories necessary, but it is inaccurate in that it raises an error if the directory already exists.

I propose that either parents=True should imply that there is no error if the directory already exists (which would be a backwards-incompatible change); or, there could be a new exist_ok=True, which could suppress the error for an existing directory. Either way, it ought to be possible to get the mkdir -p functionality easily from pathlib. And the documentation for Path.mkdir() should be updated to explain how to get this mkdir -p functionality, with the existing (inaccurate) mkdir -p mention removed.

I think we can a new exist_ok parameter indeed. It should probably be False by default, though.

I've just been writing some new code to use pathlib and ran into this one myself. An exist_ok=False is fine, although it's a slight shame that for backward compatibility we can't adopt os.makedirs() signature exactly.

Le 27/05/2014 20:32, Barry A. Warsaw a écrit :

I've just been writing some new code to use pathlib and ran into
this
one myself. An exist_ok=False is fine, although it's a slight shame that
for backward compatibility we can't adopt os.makedirs() signature exactly.

What do you mean by that? The os.makedirs() signature is
os.makedirs(name, mode=0o777, exist_ok=False)

On May 27, 2014, at 08:48 PM, Antoine Pitrou wrote:

What do you mean by that? The os.makedirs() signature is
os.makedirs(name, mode=0o777, exist_ok=False)

Right, but this is Path.mkdir's signature:

Path.mkdir(mode=0o777, parents=False)

so it's too late to make exist_ok=False the second argument (i.e. the one
after mode). Oh well.

Updated patch. Thank you Barry and Antoine.

I like it. Thanks for the contribution! Assigning to myself since I plan on working to land this in 3.5.

New changeset 8af80d68bcdc by Barry Warsaw in branch 'default':

• Issue bpo-21539: Add a exists_ok argument to Pathlib.mkdir() to mimic
  http://hg.python.org/cpython/rev/8af80d68bcdc