[Python-checkins] cpython (3.2): Issue #12149: Update the method cache after a type's dictionnary gets

Tue Jul 12 22:01:46 CEST 2011

http://hg.python.org/cpython/rev/cd40ea4087b0
changeset: 71297:cd40ea4087b0
branch: 3.2
parent: 71295:7f3dd627103b
user: Antoine Pitrou <solipsis at pitrou.net>
date: Tue Jul 12 21:57:15 2011 +0200
summary:
 Issue #12149: Update the method cache after a type's dictionnary gets
cleared by the garbage collector. This fixes a segfault when an instance
and its type get caught in a reference cycle, and the instance's
deallocator calls one of the methods on the type (e.g. when subclassing
IOBase).
Diagnosis and patch by Davide Rizzo.
files:
 Lib/test/test_io.py | 19 ++++++++++++++++++-
 Misc/ACKS | 1 +
 Misc/NEWS | 6 ++++++
 Objects/typeobject.c | 2 ++
 4 files changed, 27 insertions(+), 1 deletions(-)

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -611,7 +611,24 @@
 self.assertEqual(rawio.read(2), b"")
 
 class CIOTest(IOTest):
- pass
+
+ def test_IOBase_finalize(self):
+ # Issue #12149: segmentation fault on _PyIOBase_finalize when both a
+ # class which inherits IOBase and an object of this class are caught
+ # in a reference cycle and close() is already in the method cache.
+ class MyIO(self.IOBase):
+ def close(self):
+ pass
+
+ # create an instance to populate the method cache
+ MyIO()
+ obj = MyIO()
+ obj.obj = obj
+ wr = weakref.ref(obj)
+ del MyIO
+ del obj
+ support.gc_collect()
+ self.assertTrue(wr() is None, wr)
 
 class PyIOTest(IOTest):
 pass
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -736,6 +736,7 @@
 Nicholas Riley
 Jean-Claude Rimbault
 Juan M. Bello Rivas
+Davide Rizzo
 Anthony Roach
 Mark Roberts
 Jim Robinson
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,12 @@
 Core and Builtins
 -----------------
 
+- Issue #12149: Update the method cache after a type's dictionnary gets
+ cleared by the garbage collector. This fixes a segfault when an instance
+ and its type get caught in a reference cycle, and the instance's
+ deallocator calls one of the methods on the type (e.g. when subclassing
+ IOBase). Diagnosis and patch by Davide Rizzo.
+
 - Issue #9611, #9015: FileIO.read() clamps the length to INT_MAX on Windows.
 
 - When a generator yields, do not retain the caller's exception state on the
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -967,6 +967,8 @@
 assert(basedealloc);
 basedealloc(self);
 
+ PyType_Modified(type);
+
 /* Can't reference self beyond this point */
 Py_DECREF(type);
 
-- 
Repository URL: http://hg.python.org/cpython
