os.path.isabs() behavior changed on Windows between 3.11.3 -> 3.13.3

[juj]

Bug report

Bug description:

Was this change in behavior of os.path.isabs() intentional?

C:\emsdk\emscripten\main>%EMSDK_PYTHON%
Python 3.13.3 (tags/v3.13.3:6280bb5, Apr  8 2025, 14:47:33) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os; os.path.isabs('/usr/something')
False
>>>
KeyboardInterrupt
>>> ^Z

C:\emsdk\emscripten\main>C:\Python311\python.exe
Python 3.11.3 (tags/v3.11.3:f3909b8, Apr  4 2023, 23:49:59) [MSC v.1934 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os; os.path.isabs('/usr/something')
True
>>>

I would argue that even on Windows, having os.path.isabs('/foo/bar') return True like it used to, would make sense, though wanted to confirm that this was an intentional change that it no longer does?

CPython versions tested on:

3.13

Operating systems tested on:

Windows

[terryjreedy]

No need to include a duplicate image. (I know that this is the habit elsewhere.) We prefer copy-paste and trust that people can do it competently. Someone often copy-pastes code onto their own system to to verify anyway to retest on other versions and systems.

Yes, but questions like this should be asked on forums like https://discuss.python.org/c/help/7. See https://discuss.python.org/t/is-xyz-for-instance-os-path-isabs-behavior-change-intentional-answered/93814 for a full answer.