fix hidden var

youknowone · youknowone · commit a8f1e26a44ad · 2025-12-11T12:21:13.000+09:00
diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py
@@ -1036,8 +1036,6 @@ def check(value, expected):
             check('%spam%bar', '%sbar' % nonascii)
             check('%{}%bar'.format(nonascii), 'ham%sbar' % nonascii)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailureIfWindows("TODO: RUSTPYTHON")
     def test_expanduser(self):
         tester('ntpath.expanduser("test")', 'test')
 
diff --git a/crates/vm/src/stdlib/nt.rs b/crates/vm/src/stdlib/nt.rs
@@ -125,6 +125,13 @@ pub(crate) mod module {
         let environ = vm.ctx.new_dict();
 
         for (key, value) in env::vars() {
+            // Skip hidden Windows environment variables (e.g., =C:, =D:, =ExitCode)
+            // These are internal cmd.exe bookkeeping variables that store per-drive
+            // current directories. They cannot be modified via _wputenv() and should
+            // not be exposed to Python code.
+            if key.starts_with('=') {
+                continue;
+            }
             environ.set_item(&key, vm.new_pyobj(value), vm).unwrap();
         }
         environ
