Avoid referencing globals in emulated is_finalizing()

diff --git a/tornado/util.py b/tornado/util.py
index 174c35df681ff1183bbb27c4f1c0de433eb6c7a3..d0f83d1ff9be434d7c12cb72c105431354e46d5b 100644 (file)
--- a/tornado/util.py
+++ b/tornado/util.py
@@ -76,7 +76,8 @@ except ImportError:
         atexit.register(lambda: L.append(None))
 
         def is_finalizing():
-            return bool(L)
+            # Not referencing any globals here
+            return L != []
 
         return is_finalizing