Try to avoid invoking a new process to determine the Windows version in the platform module

[tomergert]

Feature or enhancement

Proposal:

In Lib/platform.py, there's a code aimed to determine the Windows version python runs in.

 for cmd in ('ver', 'command /c ver', 'cmd /c ver'):
 try:
 info = subprocess.check_output(cmd,
 stdin=subprocess.DEVNULL,
 stderr=subprocess.DEVNULL,
 text=True,
 encoding="locale",
 shell=True)

As much as I understand, one shouldn't invoke whole new process just to question what OS version he runs at.

so just before invoking cmd.exe, we will try to question winapi directly.

# Load ntdll.dll and call RtlGetVersion
 ntdll = ctypes.WinDLL("ntdll")
 rtl_get_version = ntdll.RtlGetVersion
 rtl_get_version(ctypes.byref(os_version))

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-129294: use winapi to determine win version before invoking cmd.exe #129295

[zooba]

This is already fallback code for if WMI doesn't work, and GetVersionEx is already provided by sys.getwindowsversion.

I don't think there's anything to change here.

[tomergert]

This is already fallback code for if WMI doesn't work, and GetVersionEx is already provided by sys.getwindowsversion.

I don't think there's anything to change here.

Thank you,. I addressed your comment in the PR
#129295 (comment)

[zware]

In agreement with Steve, I'm going to close this issue. We may be at the point that we can remove the subprocess-based fallback entirely, but being the fallback fallback I'm not sure it's worth a change. Either way it's not a pressing concern, or a performance issue.