[New-bugs-announce] [issue43620] os.path.join does not use os.sep as documentation claims

[Jared Sutton]

New submission from Jared Sutton <jpsutton at gmail.com>:

The behavior of os.path.join() does not match the documentation, in regards to the use of os.sep.  From the docs:

"""
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.
"""

The documentation clearly states that the function uses the value of os.sep (which differs based on platform).  However, if you review the 2 implementations (ntpath.py and posixpath.py), the separator character used is clearly hard-coded and doesn't reference os.sep at all.

One could say that this is either a doc bug or an implementation bug, depending on what the intended behavior is. I submit that this is an implementation bug, as one might want to use os.path.join() to construct a path to be used on a platform other than the one currently running the application. For example, a person might be running Python on Windows, but calling a web API and constructing a path for use on a remote posix system.

----------
assignee: docs at python
components: Documentation, Library (Lib)
messages: 389489
nosy: docs at python, jpsutton
priority: normal
severity: normal
status: open
title: os.path.join does not use os.sep as documentation claims
type: behavior
versions: Python 3.10, Python 3.6, Python 3.7, Python 3.8, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43620>
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