From: Michael W. Hudson <mwh@python.net>
Date: Fri, 22 Feb 2002 13:29:32 +0000 (+0000)
Subject: backport tim_one's checkin of
X-Git-Tag: v2.2.1c1~193
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bccffe226a020e89b7c78871bd46db0924be24e1;p=thirdparty%2FPython%2Fcpython.git

backport tim_one's checkin of
    revision 1.10 of test_thread.py
    revision 1.5 of test_threaded_import.py

SF bug #516372:  test_thread: unhandled exc. in thread
Fix exit races in test_thread.py and test_threaded_import.py.
I suspect the bug is provokable only under Linux (where child threads
seem to get lots of cycles before they get killed after the main thread
exits), or on multi-processor machines running other OSes.
Bugfix candidate.
---

diff --git a/Lib/test/test_thread.py b/Lib/test/test_thread.py
index 02da94e75d13..a45fb2fd5b3f 100644
--- a/Lib/test/test_thread.py
+++ b/Lib/test/test_thread.py
@@ -97,10 +97,14 @@ def task2(ident):
         if verbose:
             print 'task', ident, 'leaving barrier', i
     mutex.acquire()
-    running = running - 1
-    if running == 0:
-        done.release()
+    running -= 1
+    # Must release mutex before releasing done, else the main thread can
+    # exit and set mutex to None as part of global teardown; then
+    # mutex.release() raises AttributeError.
+    finished = running == 0
     mutex.release()
+    if finished:
+        done.release()
 
 print '\n*** Barrier Test ***'
 if done.acquire(0):
diff --git a/Lib/test/test_threaded_import.py b/Lib/test/test_threaded_import.py
index e022c5fe9241..d9f3d705738d 100644
--- a/Lib/test/test_threaded_import.py
+++ b/Lib/test/test_threaded_import.py
@@ -17,9 +17,13 @@ def task():
     x = random.randrange(1, 3)
     critical_section.acquire()
     N -= 1
-    if N == 0:
-        done.release()
+    # Must release critical_section before releasing done, else the main
+    # thread can exit and set critical_section to None as part of global
+    # teardown; then critical_section.release() raises AttributeError.
+    finished = N == 0
     critical_section.release()
+    if finished:
+        done.release()
 
 # Tricky:  When regrtest imports this module, the thread running regrtest
 # grabs the import lock and won't let go of it until this module returns.