Visitar URL original
gh-84538: add strict argument to pathlib.PurePath.relative_to by domragusa · Pull Request #19813 · python/cpython · GitHub
Skip to content

gh-84538: add strict argument to pathlib.PurePath.relative_to #19813

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
miss-islington merged 17 commits into from
Oct 28, 2022
Merged

gh-84538: add strict argument to pathlib.PurePath.relative_to #19813

Show file tree
Hide file tree
Changes from 7 commits
Commits
Show all changes
17 commits
Select commit Hold shift + click to select a range
ec64368
bpo-40358: add strict param to pathlib.PurePath.relative_to
domragusa Apr 30, 2020
6d721a0
resolve conflicts with GH-19611
domragusa May 28, 2020
09422e7
Merge branch 'python:main' into relative_to_strict_param
domragusa May 15, 2021
d9c07c2
Update Doc/library/pathlib.rst
domragusa May 15, 2021
029c3d5
fix wording in documentation as requested
domragusa May 17, 2021
01e789b
fix typo
domragusa May 17, 2021
39b24f3
change strict argument to walk_up in pathlib.PurePath.relative_to
domragusa May 29, 2021
ad9c0dd
Merge branch 'main' into relative_to_strict_param
domragusa Oct 14, 2022
8401974
make the documentation clearer
domragusa Oct 14, 2022
e255f99
Apply suggestions from code review
domragusa Oct 22, 2022
b781356
Update Lib/pathlib.py
domragusa Oct 22, 2022
7974ee9
fix doc warning
domragusa Oct 22, 2022
8a4edb5
improve variable names
domragusa Oct 22, 2022
e6cf222
remove trailing spaces
domragusa Oct 22, 2022
b8b218c
Merge branch 'main' into relative_to_strict_param
domragusa Oct 22, 2022
a4c77c2
Update Doc/library/pathlib.rst
brettcannon Oct 28, 2022
97a5e22
Merge branch 'main' into relative_to_strict_param
brettcannon Oct 28, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 24 additions & 6 deletions Doc/library/pathlib.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -538,10 +538,10 @@ Pure paths provide the following methods and properties:
True


.. method:: PurePath.relative_to(*other)
.. method:: PurePath.relative_to(*other, walk_up=False)

Compute a version of this path relative to the path represented by
*other*. If it's impossible, ValueError is raised::
*other*. If it's impossible, :exc:`ValueError` is raised::

>>> p = PurePosixPath('/etc/passwd')
>>> p.relative_to('/')
Expand All @@ -551,11 +551,29 @@ Pure paths provide the following methods and properties:
>>> p.relative_to('/usr')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "pathlib.py", line 694, in relative_to
.format(str(self), str(formatted)))
ValueError: '/etc/passwd' is not in the subpath of '/usr' OR one path is relative and the other absolute.
File "pathlib.py", line 941, in relative_to
raise ValueError(error_message.format(str(self), str(formatted)))
ValueError: '/etc/passwd' is not in the subpath of '/usr' OR one path is relative and the other is absolute.
>>> p.relative_to('/usr', walk_up=True)
PurePosixPath('../etc/passwd')
>>> p.relative_to('foo', walk_up=True)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "pathlib.py", line 941, in relative_to
raise ValueError(error_message.format(str(self), str(formatted)))
ValueError: '/etc/passwd' is not on the same drive as 'foo' OR one path is relative and the other is absolute.

When *walk_up* is False, the default, the path must start with *other*,
when it's True ``..`` entries may be added to form the relative path. In
all other cases, such as the paths referencing different drives,
:exc:`ValueError` is raised.

@barneygale barneygale Jun 24, 2021

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think this documentation needs to occur before the examples of using walk_up.

So, either move it after "ValueError is raised", or split the examples into two parts.


.. warning::
The *walk_up* option assumes that no symlinks are present in the path; you
should call :meth:`~Path.resolve` first to ensure this.
Comment thread
domragusa marked this conversation as resolved.
Outdated

NOTE: This function is part of :class:`PurePath` and works with strings. It does not check or access the underlying file structure.
.. versionadded:: 3.11
The *walk_up* argument (pre-3.11 behavior is the same as walk_up=False).


.. method:: PurePath.with_name(name)
Expand Down
7 changes: 7 additions & 0 deletions Doc/whatsnew/3.11.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,13 @@ New Modules
Improved Modules
================

pathlib
-------

:meth:`pathlib.PurePath.relative_to` now supports generating relative paths
containing ``..`` entries if its new *walk_up* keyword-only argument is set to
``True``. The new behavior is more consistent with :func:`os.path.relpath`.
(Contributed by Domenico Ragusa in :issue:`40358`.)

Optimizations
=============
Expand Down
30 changes: 22 additions & 8 deletions Lib/pathlib.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -776,10 +776,10 @@ def with_suffix(self, suffix):
return self._from_parsed_parts(self._drv, self._root,
self._parts[:-1] + [name])

def relative_to(self, *other):
def relative_to(self, *other, walk_up=False):
"""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.
related to the other path), raise ValueError.
Comment thread
domragusa marked this conversation as resolved.
"""
# For the purpose of this method, drive and root are considered
# separate parts, i.e.:
Expand All @@ -801,13 +801,27 @@ def relative_to(self, *other):
to_abs_parts = to_parts
n = len(to_abs_parts)
cf = self._flavour.casefold_parts
if (root or drv) if n == 0 else cf(abs_parts[:n]) != cf(to_abs_parts):
common = 0
Comment thread
brettcannon marked this conversation as resolved.
Outdated
for p, tp in zip(cf(abs_parts), cf(to_abs_parts)):
Comment thread
brettcannon marked this conversation as resolved.
Outdated
if p != tp:
break
common += 1
if walk_up:
failure = root != to_root
if drv or to_drv:
failure = cf([drv]) != cf([to_drv]) or (failure and n > 1)
error_message = "{!r} is not on the same drive as {!r}"
up_parts = (n-common)*['..']
else:
failure = (root or drv) if n == 0 else common != n
error_message = "{!r} is not in the subpath of {!r}"
up_parts = []
error_message += " OR one path is relative and the other is absolute."
if failure:
formatted = self._format_parsed_parts(to_drv, to_root, to_parts)
raise ValueError("{!r} is not in the subpath of {!r}"
" OR one path is relative and the other is absolute."
.format(str(self), str(formatted)))
return self._from_parsed_parts('', root if n == 1 else '',
abs_parts[n:])
raise ValueError(error_message.format(str(self), str(formatted)))
Comment thread
brettcannon marked this conversation as resolved.
return self._from_parsed_parts('', root if common == 1 else '',
up_parts+abs_parts[common:])
Comment thread
domragusa marked this conversation as resolved.
Outdated

def is_relative_to(self, *other):
"""Return True if the path is relative to another path or False.
Expand Down
82 changes: 82 additions & 0 deletions Lib/test/test_pathlib.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -629,13 +629,29 @@ def test_relative_to_common(self):
self.assertEqual(p.relative_to('a/'), P('b'))
self.assertEqual(p.relative_to(P('a/b')), P())
self.assertEqual(p.relative_to('a/b'), P())
self.assertEqual(p.relative_to(P(), walk_up=True), P('a/b'))
self.assertEqual(p.relative_to('', walk_up=True), P('a/b'))
self.assertEqual(p.relative_to(P('a'), walk_up=True), P('b'))
self.assertEqual(p.relative_to('a', walk_up=True), P('b'))
self.assertEqual(p.relative_to('a/', walk_up=True), P('b'))
self.assertEqual(p.relative_to(P('a/b'), walk_up=True), P())
self.assertEqual(p.relative_to('a/b', walk_up=True), P())
self.assertEqual(p.relative_to(P('a/c'), walk_up=True), P('../b'))
self.assertEqual(p.relative_to('a/c', walk_up=True), P('../b'))
self.assertEqual(p.relative_to(P('a/b/c'), walk_up=True), P('..'))
self.assertEqual(p.relative_to('a/b/c', walk_up=True), P('..'))
self.assertEqual(p.relative_to(P('c'), walk_up=True), P('../a/b'))
self.assertEqual(p.relative_to('c', walk_up=True), P('../a/b'))
# With several args.
self.assertEqual(p.relative_to('a', 'b'), P())
self.assertEqual(p.relative_to('a', 'b', walk_up=True), P())
# Unrelated paths.
self.assertRaises(ValueError, p.relative_to, P('c'))
self.assertRaises(ValueError, p.relative_to, P('a/b/c'))
self.assertRaises(ValueError, p.relative_to, P('a/c'))
self.assertRaises(ValueError, p.relative_to, P('/a'))
self.assertRaises(ValueError, p.relative_to, P('/'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('/a'), walk_up=True)
p = P('/a/b')
self.assertEqual(p.relative_to(P('/')), P('a/b'))
self.assertEqual(p.relative_to('/'), P('a/b'))
Expand All @@ -644,13 +660,28 @@ def test_relative_to_common(self):
self.assertEqual(p.relative_to('/a/'), P('b'))
self.assertEqual(p.relative_to(P('/a/b')), P())
self.assertEqual(p.relative_to('/a/b'), P())
self.assertEqual(p.relative_to(P('/'), walk_up=True), P('a/b'))
self.assertEqual(p.relative_to('/', walk_up=True), P('a/b'))
self.assertEqual(p.relative_to(P('/a'), walk_up=True), P('b'))
self.assertEqual(p.relative_to('/a', walk_up=True), P('b'))
self.assertEqual(p.relative_to('/a/', walk_up=True), P('b'))
self.assertEqual(p.relative_to(P('/a/b'), walk_up=True), P())
self.assertEqual(p.relative_to('/a/b', walk_up=True), P())
self.assertEqual(p.relative_to(P('/a/c'), walk_up=True), P('../b'))
self.assertEqual(p.relative_to('/a/c', walk_up=True), P('../b'))
self.assertEqual(p.relative_to(P('/a/b/c'), walk_up=True), P('..'))
self.assertEqual(p.relative_to('/a/b/c', walk_up=True), P('..'))
self.assertEqual(p.relative_to(P('/c'), walk_up=True), P('../a/b'))
self.assertEqual(p.relative_to('/c', walk_up=True), P('../a/b'))
# Unrelated paths.
self.assertRaises(ValueError, p.relative_to, P('/c'))
self.assertRaises(ValueError, p.relative_to, P('/a/b/c'))
self.assertRaises(ValueError, p.relative_to, P('/a/c'))
self.assertRaises(ValueError, p.relative_to, P())
self.assertRaises(ValueError, p.relative_to, '')
self.assertRaises(ValueError, p.relative_to, P('a'))
self.assertRaises(ValueError, p.relative_to, P(''), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('a'), walk_up=True)

def test_is_relative_to_common(self):
P = self.cls
Expand Down Expand Up @@ -1113,6 +1144,16 @@ def test_relative_to(self):
self.assertEqual(p.relative_to('c:foO/'), P('Bar'))
self.assertEqual(p.relative_to(P('c:foO/baR')), P())
self.assertEqual(p.relative_to('c:foO/baR'), P())
self.assertEqual(p.relative_to(P('c:'), walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to('c:', walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to(P('c:foO'), walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('c:foO', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('c:foO/', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to(P('c:foO/baR'), walk_up=True), P())
self.assertEqual(p.relative_to('c:foO/baR', walk_up=True), P())
self.assertEqual(p.relative_to(P('C:Foo/Bar/Baz'), walk_up=True), P('..'))
self.assertEqual(p.relative_to(P('C:Foo/Baz'), walk_up=True), P('../Bar'))
self.assertEqual(p.relative_to(P('C:Baz/Bar'), walk_up=True), P('../../Foo/Bar'))
# Unrelated paths.
self.assertRaises(ValueError, p.relative_to, P())
self.assertRaises(ValueError, p.relative_to, '')
Expand All @@ -1123,6 +1164,13 @@ def test_relative_to(self):
self.assertRaises(ValueError, p.relative_to, P('C:/Foo'))
self.assertRaises(ValueError, p.relative_to, P('C:Foo/Bar/Baz'))
self.assertRaises(ValueError, p.relative_to, P('C:Foo/Baz'))
self.assertRaises(ValueError, p.relative_to, P(), walk_up=True)
self.assertRaises(ValueError, p.relative_to, '', walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('d:'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('/'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('/Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('C:/Foo'), walk_up=True)
p = P('C:/Foo/Bar')
self.assertEqual(p.relative_to(P('c:')), P('/Foo/Bar'))
self.assertEqual(p.relative_to('c:'), P('/Foo/Bar'))
Expand All @@ -1135,6 +1183,20 @@ def test_relative_to(self):
self.assertEqual(p.relative_to('c:/foO/'), P('Bar'))
self.assertEqual(p.relative_to(P('c:/foO/baR')), P())
self.assertEqual(p.relative_to('c:/foO/baR'), P())
self.assertEqual(p.relative_to(P('c:'), walk_up=True), P('/Foo/Bar'))
self.assertEqual(p.relative_to('c:', walk_up=True), P('/Foo/Bar'))
self.assertEqual(str(p.relative_to(P('c:'), walk_up=True)), '\\Foo\\Bar')
self.assertEqual(str(p.relative_to('c:', walk_up=True)), '\\Foo\\Bar')
self.assertEqual(p.relative_to(P('c:/'), walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to('c:/', walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to(P('c:/foO'), walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('c:/foO', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('c:/foO/', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to(P('c:/foO/baR'), walk_up=True), P())
self.assertEqual(p.relative_to('c:/foO/baR', walk_up=True), P())
self.assertEqual(p.relative_to('C:/Baz', walk_up=True), P('../Foo/Bar'))
self.assertEqual(p.relative_to('C:/Foo/Bar/Baz', walk_up=True), P('..'))
self.assertEqual(p.relative_to('C:/Foo/Baz', walk_up=True), P('../Bar'))
# Unrelated paths.
self.assertRaises(ValueError, p.relative_to, P('C:/Baz'))
self.assertRaises(ValueError, p.relative_to, P('C:/Foo/Bar/Baz'))
Expand All @@ -1145,6 +1207,12 @@ def test_relative_to(self):
self.assertRaises(ValueError, p.relative_to, P('/'))
self.assertRaises(ValueError, p.relative_to, P('/Foo'))
self.assertRaises(ValueError, p.relative_to, P('//C/Foo'))
self.assertRaises(ValueError, p.relative_to, P('C:Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('d:'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('d:/'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('/'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('/Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('//C/Foo'), walk_up=True)
# UNC paths.
p = P('//Server/Share/Foo/Bar')
self.assertEqual(p.relative_to(P('//sErver/sHare')), P('Foo/Bar'))
Expand All @@ -1155,11 +1223,25 @@ def test_relative_to(self):
self.assertEqual(p.relative_to('//sErver/sHare/Foo/'), P('Bar'))
self.assertEqual(p.relative_to(P('//sErver/sHare/Foo/Bar')), P())
self.assertEqual(p.relative_to('//sErver/sHare/Foo/Bar'), P())
self.assertEqual(p.relative_to(P('//sErver/sHare'), walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to('//sErver/sHare', walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to('//sErver/sHare/', walk_up=True), P('Foo/Bar'))
self.assertEqual(p.relative_to(P('//sErver/sHare/Foo'), walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('//sErver/sHare/Foo', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to('//sErver/sHare/Foo/', walk_up=True), P('Bar'))
self.assertEqual(p.relative_to(P('//sErver/sHare/Foo/Bar'), walk_up=True), P())
self.assertEqual(p.relative_to('//sErver/sHare/Foo/Bar', walk_up=True), P())
self.assertEqual(p.relative_to(P('//sErver/sHare/bar'), walk_up=True), P('../Foo/Bar'))
self.assertEqual(p.relative_to('//sErver/sHare/bar', walk_up=True), P('../Foo/Bar'))
# Unrelated paths.
self.assertRaises(ValueError, p.relative_to, P('/Server/Share/Foo'))
self.assertRaises(ValueError, p.relative_to, P('c:/Server/Share/Foo'))
self.assertRaises(ValueError, p.relative_to, P('//z/Share/Foo'))
self.assertRaises(ValueError, p.relative_to, P('//Server/z/Foo'))
self.assertRaises(ValueError, p.relative_to, P('/Server/Share/Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('c:/Server/Share/Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('//z/Share/Foo'), walk_up=True)
self.assertRaises(ValueError, p.relative_to, P('//Server/z/Foo'), walk_up=True)

def test_is_relative_to(self):
P = self.cls
Expand Down
1 change: 1 addition & 0 deletions Misc/ACKS
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1409,6 +1409,7 @@ Pierre Quentel
Brian Quinlan
Anders Qvist
Thomas Rachel
Domenico Ragusa
Ram Rachum
Jeffrey Rackauckas
Jérôme Radix
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2020-04-30-02-15-08.bpo-40358.A4ygqe.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Add walk_up argument in :meth:`pathlib.PurePath.relative_to`.