fix(bootstrap): use retry loop for win32 version lookup in site init template

news/win32_version_lookup.fixed.md

@@ -0,0 +1,3 @@
+Fixed a flaky error on Windows 2022 when looking up the win32 version during
+site initialization by retrying the lookup
+([#3721](https://github.com/bazel-contrib/rules_python/issues/3721)).

python/private/site_init_template.py

@@ -98,7 +98,15 @@ def _get_windows_path_with_unc_prefix(path):
     # Related doc: https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=cmd#enable-long-paths-in-windows-10-version-1607-and-later
     import platform
 
-    if platform.win32_ver()[1] >= "10.0.14393":
+    win32_version = None
+    # Windows 2022 with Python 3.12.8 gives flakey errors, so try a couple times.
+    for _ in range(3):
+        try:
+            win32_version = platform.win32_ver()[1]
+            break
+        except (ValueError, KeyError):
+            pass
+    if win32_version and win32_version >= "10.0.14393":
         return path
 
     # import sysconfig only now to maintain python 2.6 compatibility