Path.relative_to() taking multiple arguments could be better documented

[anntzer]

BPO	34526
Nosy	@anntzer, @barneygale
PRs	bpo-34526：[doc] Add description and examples of multiple arguments for Path.relative_to #31368

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-08-28.08:42:29.205>
labels = ['easy', '3.11', '3.9', '3.10', 'docs']
title = 'Path.relative_to() taking multiple arguments could be better documented'
updated_at = <Date 2022-02-16.08:01:06.637>
user = 'https://github.com/anntzer'

bugs.python.org fields:

activity = <Date 2022-02-16.08:01:06.637>
actor = 'python-dev'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2018-08-28.08:42:29.205>
creator = 'Antony.Lee'
dependencies = []
files = []
hgrepos = []
issue_num = 34526
keywords = ['patch', 'easy']
message_count = 1.0
messages = ['324224']
nosy_count = 4.0
nosy_names = ['docs@python', 'python-dev', 'Antony.Lee', 'barneygale']
pr_nums = ['31368']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue34526'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

Linked PRs

• gh-78707: deprecate passing >1 argument to PurePath.[is_]relative_to() #94469
• GH-78707: Drop deprecated pathlib.PurePath.[is_]relative_to() arguments #118780

[anntzer]

Currently, the docs for Path.relative_to read

 PurePath.relative_to(*other)
 Compute a version of this path relative to the path represented by other. If it’s impossible, ValueError is raised: (examples follow)

It's a bit confusing why other is a star-args, especially as no example actually passes more than one argument to relative_to.

The docstring is a tiny bit clearer:

Return the relative path to another path identified by the passed
arguments. If the operation is not possible (because this is not
a subpath of the other path), raise ValueError.

Effectively, a Path is constructed from all *other args and used as base for the computation of the relative path. It looks a bit like a misfeature to me, but at least it could be better documented (e.g. by adding Path("/tmp/foo/bar").relative_to("/tmp", "foo") == Path("bar") as example in the docs).

[barneygale]

I think this is a mis-feature and we should look at deprecating + removing it, rather than documenting it.

Consider that pathlib has many other methods that accept a single other path, like rename(), replace(), symlink_to() and hardlink_to().

The only methods that should support *args should be joinpath() and the PurePath initialiser IMO.

[JelleZijlstra]

Agree that this is a misfeature. We'll have to go through a deprecation cycle to remove it though, since it's at least kind of documented.