GH-73991: Add pathlib.Path.move()

[barneygale]

Add a Path.move() method that moves a file or directory tree, and returns a new Path instance pointing to the target.

This method is similar to shutil.move(), except that it doesn't accept a copy_function argument, and it doesn't check whether the destination is an existing directory.

In pathlib's private ABCs, PathBase.move() uses the copy() and delete() methods to move files and directories.

• Issue: Support moving across filesystems in pathlib.Path, as shutil.move() does #73991

---

📚 Documentation preview 📚: https://cpython-previews--122073.org.readthedocs.build/

[barneygale]

Marking this as a draft as it will need to be revised once #122368 and #122369 land.

[barneygale]

Should be ready to review again :-)

This isn't quite the last PR in this series. I'll log another to add copy_into() and move_into(), and then post to discuss.python.org about perhaps eliminating some/all of the ignore_errors, on_error and ignore arguments to delete() and copy().

[barneygale]

Sorry for flip-flopping. I've moved the copy() changes into their own PR (#122924) so I'll mark this as a draft once again (-:

[picnixz]

I've reviewed the other PR. Do you want me to review this one now or should I wait?

[barneygale]

I've reviewed the other PR. Do you want me to review this one now or should I wait?

Sorry for the slow reply - I think it would be best to wait for the other PR to land before reviewing this.

[barneygale]

Hey @picnixz, this is ready to review again FYI. Thanks in advance :)

[picnixz]

I think it would be good to also have assertions before calling move(). That way you really know how the state of the files change before/after the test (and that way, we are sure that we are in a correct test environment). I did not mark all tests that need this but any test that does self.assertTrue(target.exists()) after moving should do self.assertFalse(target.exists()) before moving (and if the target is to be overwritten, then it should check that it's content changed).

[picnixz]

Just me thinking loud, but do you think we should have a boolean to not overwrite an existing target (in which case, a FileExistsError would be raised)?

[barneygale]

We could add a clobber=True argument, but I think that would be a separate PR.

[picnixz]

I would have thought of strict (strict=False by default, strict=True would raise) or replace=True. But we can address this question later. Otherwise, it's just a three liner where users would do if not os.exists(target) if they want to avoid replacing files.

[barneygale]

"Clobber" has some currency already, e.g. in mv --no-clobber. But yeah, let's discuss later.

[barneygale]

I don't understand why we'd make assertions before calling move() - we already know the state of the test directory (self.base) because it's configured to our specification in setUp(). If we applied this logic consistently we'd need to adjust almost every test case in DummyPathTest and PathTest!

[picnixz]

I don't understand why we'd make assertions before calling move() - we already know the state of the test directory (self.base) because it's configured to our specification in setUp().

I shouldn't make review at 3 AM... Yes, why didn't I think about it. So yes, it's fine (I'm marking my comments as resolved). Sorry Barney for the time loss :(

[barneygale]

I shouldn't make review at 3 AM... Yes, why didn't I think about it. So yes, it's fine (I'm marking my comments as resolved). Sorry Barney for the time loss :(

Oh now, don't be silly! I really appreciate all your help with this PR and others, I apologise if I came off too strongly in my previous comment. I consider these sorts of discussions a great use of my time :)

[picnixz]

I apologise if I came off too strongly in my previous comment. I consider these sorts of discussions a great use of my time :)

No your comment was definitely legitimate! I also appreciate your review and feedback on my fnmatch issues / PRs!

[picnixz]

All good for me! I'll leave the discussion on clubber opened so that you can create a separate issue from the comment if you want.

[barneygale]

Amazing, thanks so much! I'll get back to your fnmatch stuff shortly!