Repository navigation
Fix error message for ntpath.commonpath #117381
Description
Bug report
Bug description:
>>> import ntpath
>>> ntpath.commonpath(["/foo", "foo"])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<frozen ntpath>", line 808, in commonpath
ValueError: Can't mix absolute and relative paths/foo is not an absolute path, but a rooted path, which can't be mixed with not-rooted paths.
CPython versions tested on:
CPython main branch
Operating systems tested on:
Windows
Activity
aisk commented on Mar 30, 2024
I did some googling and found that Microsoft has a document which describes "relative rooted path": https://learn.microsoft.com/en-us/dotnet/api/system.io.path.ispathrooted?view=net-8.0#remarks
So I think the relative rooted path should be something like C:foo (please notice that it's not C:/foo), but /foo still is an absolute path. And ntpath.isabs('/foo') returns True, so I think it's an absolute path.
nineteendo commented on Mar 30, 2024
That was recently changed:
The error message could also be "Can't mix rooted and not-rooted paths" as /foo is rooted and foo is not.
zooba commented on Apr 2, 2024
How does this change make life better or easier for those encountering this message?
At first glance, it appears to be getting into overly precise terminology that doesn't help educate or correct the caller.
nineteendo commented on Apr 2, 2024
The error message states: "Can't mix absolute and relative paths".
But /foo & foo are both relative according to ntpath.isabs():
So, this error message is factually incorrect.
But /foo is rooted and foo is not, so that's what the new error message is in that case.
On a side note, it could be useful to add os.path.isrooted.
gh-117381: Improve error messages for ntpath.commonpath() (GH-117382)
pythongh-117381: Improve error messages for ntpath.commonpath() (pyth…