bpo-39906: add follow_symlinks parameter to pathlib.Path.stat() and chmod()

[barneygale]

Backwards-compatible change that makes this work:

import pathlib
p = pathlib.Path("/some/symlink")
assert p.stat(follow_symlinks=True) == p.stat()
assert p.stat(follow_symlinks=False) == p.lstat()

This brings pathlib in line with the newish follow_symlinks parameters in os functions, and arguably provides a more explicit (and nicer?) interface.

For consistency I've applied the same change to chmod(), though as far as I can tell, changing permissions on symlinks is only available on some BSDs (see bpo-7479)

https://bugs.python.org/issue39906

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[pitrou]

The addition looks good on the principle. Two comments though. Also, you'll need to rebase / merge from master.

[bedevere-bot]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[csabella]

@barneygale, please address the review comments. Thank you!

[barneygale]

Rebased + docs versions fixed

[barneygale]

I have made the requested changes; please review again

[bedevere-bot]

Thanks for making the requested changes!

@pitrou: please review the changes made to this pull request.

[russelldavis]

This is great, thanks. Not sure whether it's out of scope for this PR, but it might also be nice to add the follow_symlinks param to some of the methods that call stat() internally, in particular is_file() and is_dir() (this would be consistent with those same methods on os.DirEntry).

[barneygale]

@pitrou bumping this one! Think it's ready for review if you have the time

[zooba]

Sorry for the slow reviews. This looks fine to me, except it'll land in 3.10, and so the docs need to be updated to reflect that.

[barneygale]

Thanks for the review - I've updated the .. versionchanged bits.

Changes have been made

[zooba]

Just an FYI @barneygale, we squash merge at the end, so there's no need to rebase and force push PRs (merging and regular push is fine). All it does is break the review history.

[barneygale]

Just an FYI @barneygale, we squash merge at the end, so there's no need to rebase and force push PRs (merging and regular push is fine). All it does is break the review history.

Good to know, thank you.