Thanks to Detlef Lannert for pointing out a typo in the code that

uses _DummyMutex on platforms without threads.

diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index 99177f539f125ac23e57f4b7c1b8a725a7f8e75e..b981084b8b10c18b23fe2c231b75827b1bbcfad4 100644 (file)
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -249,7 +249,7 @@ except ImportError:
         release = acquire
 
     _counter = _ThreadSafeCounter(_DummyMutex())
-    _tempdir_lock = _DummyMutes()
+    _tempdir_lock = _DummyMutex()
     del _DummyMutex
 
 else: