[Python-checkins] r75127 - in python/branches/release25-maint: Lib/test/test_threading_local.py Misc/NEWS Modules/threadmodule.c
philip.jenvey
python-checkins at python.org
Tue Sep 29 07:30:43 CEST 2009
Author: philip.jenvey
Date: Tue Sep 29 07:30:42 2009
New Revision: 75127
Log:
#6990: clear threading.local's key only after its thread state is removed:
fixes local subclasses leaving old state around after a ref cycle GC which
could be recycled by new locals
(backported from r75123)
Modified:
python/branches/release25-maint/Lib/test/test_threading_local.py
python/branches/release25-maint/Misc/NEWS
python/branches/release25-maint/Modules/threadmodule.c
Modified: python/branches/release25-maint/Lib/test/test_threading_local.py
==============================================================================
--- python/branches/release25-maint/Lib/test/test_threading_local.py (original)
+++ python/branches/release25-maint/Lib/test/test_threading_local.py Tue Sep 29 07:30:42 2009
@@ -1,3 +1,5 @@
+import gc
+import threading
import unittest
from doctest import DocTestSuite
from test import test_support
@@ -8,7 +10,6 @@
# of a threading.local derived class, the per-thread dictionary
# is created but not correctly set on the object.
# The first member set may be bogus.
- import threading
import time
class Local(threading.local):
def __init__(self):
@@ -29,6 +30,44 @@
for t in threads:
t.join()
+ def test_derived_cycle_dealloc(self):
+ # http://bugs.python.org/issue6990
+ class Local(threading.local):
+ pass
+ locals = None
+ passed = [False]
+ e1 = threading.Event()
+ e2 = threading.Event()
+
+ def f():
+ # 1) Involve Local in a cycle
+ cycle = [Local()]
+ cycle.append(cycle)
+ cycle[0].foo = 'bar'
+
+ # 2) GC the cycle (triggers threadmodule.c::local_clear
+ # before local_dealloc)
+ del cycle
+ gc.collect()
+ e1.set()
+ e2.wait()
+
+ # 4) New Locals should be empty
+ passed[0] = all(not hasattr(local, 'foo') for local in locals)
+
+ t = threading.Thread(target=f)
+ t.start()
+ e1.wait()
+
+ # 3) New Locals should recycle the original's address. Creating
+ # them in the thread overwrites the thread state and avoids the
+ # bug
+ locals = [Local() for i in range(10)]
+ e2.set()
+ t.join()
+
+ self.assertTrue(passed[0])
+
def test_main():
suite = DocTestSuite('_threading_local')
Modified: python/branches/release25-maint/Misc/NEWS
==============================================================================
--- python/branches/release25-maint/Misc/NEWS (original)
+++ python/branches/release25-maint/Misc/NEWS Tue Sep 29 07:30:42 2009
@@ -9,6 +9,12 @@
*Release date: XX-XXX-20XX*
+Core and builtins
+-----------------
+
+- Issue #6990: Fix threading.local subclasses leaving old state around
+ after a reference cycle GC which could be recycled by new locals.
+
Library
-------
Modified: python/branches/release25-maint/Modules/threadmodule.c
==============================================================================
--- python/branches/release25-maint/Modules/threadmodule.c (original)
+++ python/branches/release25-maint/Modules/threadmodule.c Tue Sep 29 07:30:42 2009
@@ -228,7 +228,6 @@
static int
local_clear(localobject *self)
{
- Py_CLEAR(self->key);
Py_CLEAR(self->args);
Py_CLEAR(self->kw);
Py_CLEAR(self->dict);
@@ -250,6 +249,7 @@
PyDict_DelItem(tstate->dict, self->key);
}
+ Py_XDECREF(self->key);
local_clear(self);
self->ob_type->tp_free((PyObject*)self);
}
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