Description

assignee = None
closed_at = None
created_at = <Date 2018-05-04.18:39:06.316>
labels = ['easy', 'type-bug', '3.9', '3.10', '3.11', 'library', 'docs']
title = '[doc] Behavior of os.path.join does not match documentation'
updated_at = <Date 2021-09-02.08:33:07.143>
user = 'https://bugs.python.org/MichaelKlatt'

activity = <Date 2021-09-02.08:33:07.143>
actor = 'Rainald Koch'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'Library (Lib)']
creation = <Date 2018-05-04.18:39:06.316>
creator = 'Michael Klatt'
dependencies = []
files = []
hgrepos = []
issue_num = 33426
keywords = ['patch', 'easy']
message_count = 5.0
messages = ['316184', '316194', '316223', '400436', '400903']
nosy_count = 6.0
nosy_names = ['SilentGhost', 'docs@python', 'zach.ware', 'Michael Klatt', 'Rainald Koch', 'DonnaDia']
pr_nums = ['28003']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue33426'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

Activity

1. MichaelKlatt commented on May 4, 2018

   

   MichaelKlattmannequin

   on May 4, 2018

   MannequinAuthor

   More actions

   The behavior of os.path.join() regarding path separators does not match the documentation. This affects Python 3.6, and goes back to at least Python 2.7.

   From the documenation:

   "The return value is the concatenation of path and any members of *paths with exactly one directory separator (os.sep) following each non-empty part except the last, meaning that the result will only end in a separator if the last part is empty."

   To me, this means that join will remove extraneous separators from the path, and that the only way to produce a trailing separator is to use join "" as the final path segment.

   I expect os.path.join("/abc//", "def/") to produce the string "/abc/def" based on the documentation, but what it actually produces is "abc//def/".
2. MichaelKlatt

   assigned

   docspython

   on May 4, 2018
3. MichaelKlatt

   added

   docsDocumentation in the Doc dirDocumentation in the Doc dir

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on May 4, 2018
4. SilentGhost commented on May 5, 2018

   

   SilentGhostmannequin

   on May 5, 2018

   Mannequin

   More actions

   your example actually produces '/abc//def/'.

   However, I'm not sure where do you get the idea that it should clean up internal directory separators or do anything at all with the strings in paths. To me it reads like it's concatenating arguments skipping over the empty ones unless it's also the last one.

   In any case, what would you propose to fix the language to describe the behaviour more clear?
5. MichaelKlatt commented on May 5, 2018

   

   MichaelKlattmannequin

   on May 5, 2018

   MannequinAuthor

   More actions

   For me, the ambiguity is due to the phrases "exactly one directory separator" and "the only way to produce a trailing separator".

   I would suggest:

   "The return value is the concatenation of path and any members of *paths so that there is a directory separator (os.sep) following each part except the last. An empty part is ignored unless it is the last part, in which case the result will end in a separator."

   Or:

   "The return value is the concatenation of path and any members of *paths such that there is guaranteed to be a directory separator (os.sep) following each part except the last. An empty part is ignored unless it is the last part, in which case the result will end in a separator."
6. iritkatriel

   added

   easy

   3.9 (EOL)end of lifeend of life

   3.10 (EOL)end of lifeend of life

   3.11only security fixesonly security fixes

   on Aug 9, 2021
7. iritkatriel

   changed the title [-]Behavior of os.path.join does not match documentation[/-] [+][doc] Behavior of os.path.join does not match documentation[/+] on Aug 9, 2021
8. DonnaDia commented on Aug 27, 2021

   

   DonnaDiamannequin

   on Aug 27, 2021

   Mannequin

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   Hi, I'm working on it. I will provide the pull request within 3 days.
9. Rainald62 commented on Sep 2, 2021

   

   Rainald62mannequin

   on Sep 2, 2021

   Mannequin

   More actions

   Minimal changes that would largely reduce the likelihood of being misunderstood: Remove "intelligently" or replace "following" by "added after".
10. ezio-melotti

    transferred this issue fromon Apr 10, 2022
11. hauntsaninja

    added 2 commits that reference this issue on Jan 29, 2023

    pythongh-77607: Improve accuracy of os.path.join docs

    392c285

    gh-77607: Improve accuracy of os.path.join docs (#101406)

    909a674
12. miss-islington

    added 4 commits that reference this issue on Jan 31, 2023

    pythongh-77607: Improve accuracy of os.path.join docs (pythonGH-101406)

    51b00e2

    pythongh-77607: Improve accuracy of os.path.join docs (pythonGH-101406)

    46a47ac

    gh-77607: Improve accuracy of os.path.join docs (GH-101406)

    f36c272

    gh-77607: Improve accuracy of os.path.join docs (GH-101406)

    a79dd88
13. hauntsaninja

    closed this as completedon Jan 31, 2023
14. mdboom

    added a commit that references this issue on Jan 31, 2023

    pythongh-77607: Improve accuracy of os.path.join docs (python#101406)

    1a51ee1
15. carljm

    added a commit that references this issue on Jan 31, 2023

    Merge branch 'main' into inlinecomp2

    ed3209b

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