commit 2a3f4899c63806439e5bcea0c30f7e6a6295a763
author Shreyan Avigyan <shreyan.avigyan@gmail.com> Thu Apr 22 22:13:37 2021 +0530
committer GitHub <noreply@github.com> Thu Apr 22 17:43:37 2021 +0100
tree c7f22925627748c1c5f71f0ea3f2948112512fac
parent a07da09ad5bd7d234ccd084a3a0933c290d1b592

bpo-43284: Update platform.win32_ver to use _syscmd_ver instead of sys.getwindowsversion() (GH-25500)

The sys module uses the kernel32.dll version number, which can vary from the "actual" Windows version.
Since the best option for getting the version is WMI (which is expensive), we switch back to launching cmd.exe (which is also expensive, but a lot less code on our part).
sys.getwindowsversion() is not updated to avoid launching executables from that module.

Lib/platform.py

diff --git a/Lib/platform.py b/Lib/platform.py
index d567dd1..d298a42 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -239,11 +239,9 @@ def _norm_version(version, build=''):
     if build:
         l.append(build)
     try:
-        ints = map(int, l)
+        strings = list(map(str, map(int, l)))
     except ValueError:
         strings = l
-    else:
-        strings = list(map(str, ints))
     version = '.'.join(strings[:3])
     return version
 
@@ -365,17 +363,20 @@ def win32_ver(release='', version='', csd='', ptype=''):
         return release, version, csd, ptype
 
     winver = getwindowsversion()
-    maj, min, build = winver.platform_version or winver[:3]
-    version = '{0}.{1}.{2}'.format(maj, min, build)
+    try:
+        major, minor, build = map(int, _syscmd_ver()[2].split('.'))
+    except ValueError:
+        major, minor, build = winver.platform_version or winver[:3]
+    version = '{0}.{1}.{2}'.format(major, minor, build)
 
-    release = (_WIN32_CLIENT_RELEASES.get((maj, min)) or
-               _WIN32_CLIENT_RELEASES.get((maj, None)) or
+    release = (_WIN32_CLIENT_RELEASES.get((major, minor)) or
+               _WIN32_CLIENT_RELEASES.get((major, None)) or
                release)
 
     # getwindowsversion() reflect the compatibility mode Python is
     # running under, and so the service pack value is only going to be
     # valid if the versions match.
-    if winver[:2] == (maj, min):
+    if winver[:2] == (major, minor):
         try:
             csd = 'SP{}'.format(winver.service_pack_major)
         except AttributeError:
@@ -384,8 +385,8 @@ def win32_ver(release='', version='', csd='', ptype=''):
 
     # VER_NT_SERVER = 3
     if getattr(winver, 'product_type', None) == 3:
-        release = (_WIN32_SERVER_RELEASES.get((maj, min)) or
-                   _WIN32_SERVER_RELEASES.get((maj, None)) or
+        release = (_WIN32_SERVER_RELEASES.get((major, minor)) or
+                   _WIN32_SERVER_RELEASES.get((major, None)) or
                    release)
 
     try: