RetroBBS - comp.lang.python - Re: pathlib.Path.is_file vs os.path.isfile difference

Re: pathlib.Path.is_file vs os.path.isfile difference

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From: grant.b.edwards@gmail.com (Grant Edwards)
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Subject: Re: pathlib.Path.is_file vs os.path.isfile difference
Date: Fri, 8 Mar 2024 18:39:51 -0500 (EST)
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by: Grant Edwards - Fri, 8 Mar 2024 23:39 UTC

On 2024-03-08, Thomas Passin via Python-list <python-list@python.org> wrote:
>
>> Hi, I tested this with Python 3.8. Good to know that this was fixed!
>
> We just learned a few posts back that it might be specific to Linux; I
> ran it on Windows.

On Linux, the limit is imposed by the filesystem. Most of the "real"
filesystems on Linux have a 255 character limit, a few support 256,
and some of the legacy filesystems have lower limits. Reiser4 is the
only one that's even remotely common which supports more than 256 --
according to https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits
it supports filenames up to 3976 bytes long.

NB: The behavior when the limit is exceeded might also vary from one
filesystem to another.

In any case, the pathlib docs for is_file() are explicit: any errors
from the underlying OS and libraries will be propogated. There is
nothing to fix.

https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_file

Path.is_file()

Return True if the path points to a regular file (or a symbolic
link pointing to a regular file), False if it points to another
kind of file.

False is also returned if the path doesn’t exist or is a broken
symlink; other errors (such as permission errors) are propagated.

The bigger the theory the better.

devel / comp.lang.python / Re: pathlib.Path.is_file vs os.path.isfile difference

Subject	Author
Re: pathlib.Path.is_file vs os.path.isfile difference	Grant Edwards