gh-123853: Cleanup Windows 95 locale fallback support

[mokurin000]

This removed the dead code windows_locale dict, as Windows introduced LOCALE_SISO639LANGNAME and LOCALE_SISO3166CTRYNAME since Windows 98.

Changes:

• Removed dead code windows_locale dict from Lib/locale.py
• Removed 0x fallback branch for Windows 95 or earlier in Modules/_localemodule.c
• Applied ruff formatting to Lib/locale.py

---

• Issue: locale.windows_locale: Incorrect Windows locale for Cambodian #123853

[mokurin000]

cc. @malemburg @serhiy-storchaka

Hi! Could you take a look on these changes?

[malemburg]

Are you sure that _locale._getdefaultlocale() will no longer return a Windows locale code ?

[mokurin000]

Are you sure that _locale._getdefaultlocale() will no longer return a Windows locale code ?

As far as I know, LOCALE_SISO639LANGNAME and LOCALE_SISO3166CTRYNAME are documented as introduced since Windows ME/98, if that stands correctly, the hex code fallback is never getting used since Python 2.6, which dropped support to Windows 95/98/ME (NT 4).

Looking into git blame, the fallback code was written at 26 years ago 8f017a0, but it never get removed, and surprisingly the dictionary was maintained even after Windows 95 support were entirely removed 0a86694

[malemburg]

I think we should still leave a guard in the code, so that such codes do not leak outside the function. The guard should raise an exception and let the user know that something is wrong.

Also, please have a look on Github whether the windows_locale is in use by Python 3 code. We may have to do a deprecation cycle (though it was already indirectly put through this as part of the now undone deprecation of getdefaultencoding()).

[mokurin000]

I think we should still leave a guard in the code, so that such codes do not leak outside the function. The guard should raise an exception and let the user know that something is wrong.

With the current mechanism, if any of LOCALE_SISO3166CTRYNAME, LOCALE_SISO639LANGNAME was not avaliable, for code a None is returned, and the legacy code in that case (if ever executed) will return None as code when the hex code not found in windows_locale
I will add that into documentation

Also, please have a look on Github whether the windows_locale is in use by Python 3 code. We may have to do a deprecation cycle (though it was already indirectly put through this as part of the now undone deprecation of getdefaultencoding()).

Okay, I will do so soon as have time

[mokurin000]

Right, undocumented though, there are many code relying on the windows_locale dictionary, it cannot be simply removed..
By the way, where shall I mark a dictionary as deprecated?

[bedevere-app]

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[mokurin000]

Now I believe it does no impact to python users, removed the NEWS entry

[bedevere-app]

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[serhiy-storchaka]

Should not _locale._getdefaultlocale() raise an exception if the locale is not found (this should never happen on modern Windows)?

[mokurin000]

Should not _locale._getdefaultlocale() raise an exception if the locale is not found (this should never happen on modern Windows)?

Okay, I will edit accordingly

[bedevere-app]

Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool.

If this change has little impact on Python users, wait for a maintainer to apply the skip news label instead.

[serhiy-storchaka]

Suggested change

	Removed Windows 95 compatibility code from :func:`_locale._getdefaultlocale`.
	Removed Windows 95 compatibility code from :func:`locale.getdefaultlocale`.

_locale._getdefaultlocale is an implementation detail. The public interface is locale.getdefaultlocale.

[serhiy-storchaka]

This is an implementation detail. And the exception should never be raised.

[malemburg]

Just to clarify: If the internal API returns an OSError, the Python API should return None.

With "guard" I meant that we don't allow one of these Windows locale codes to be returned by locale.getdefaultencoding() - the API is supposed to return a string or None as code.