[Python-checkins] python/dist/src/Misc NEWS, 1.831.4.156, 1.831.4.157

tim_one at users.sourceforge.net tim_one at users.sourceforge.net
Sun Oct 31 02:13:39 CEST 2004

Update of /cvsroot/python/python/dist/src/Misc
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv2582/Misc

Modified Files:
      Tag: release23-maint
Log Message:
SF 1055820: weakref callback vs gc vs threads

In cyclic gc, clear all weakrefs to unreachable objects before allowing any
Python code (weakref callbacks or __del__ methods) to run.

This is a critical bugfix, affecting all versions of Python since weakrefs
were introduced.

Index: NEWS
RCS file: /cvsroot/python/python/dist/src/Misc/NEWS,v
retrieving revision 1.831.4.156
retrieving revision 1.831.4.157
diff -u -d -r1.831.4.156 -r1.831.4.157
--- NEWS	20 Oct 2004 11:55:54 -0000	1.831.4.156
+++ NEWS	31 Oct 2004 00:13:05 -0000	1.831.4.157
@@ -12,6 +12,17 @@
 Core and builtins
+- Bug #1055820 Cyclic garbage collection was not protecting against that
+  calling a live weakref to a piece of cyclic trash could resurrect an
+  insane mutation of the trash if any Python code ran during gc (via
+  running a dead object's __del__ method, running another callback on a
+  weakref to a dead object, or via any Python code run in any other thread
+  that managed to obtain the GIL while a __del__ or callback was running
+  in the thread doing gc).  The most likely symptom was "impossible"
+  ``AttributeEror`` exceptions, appearing seemingly at random, on weakly
+  referenced objects.  The cure was to clear all weakrefs to unreachable
+  objects before allowing any callbacks to run.
 - Bug #951851: Python crashed when reading import table of certain
   Windows DLLs
@@ -88,7 +99,7 @@
 - Bug #679953: zipfile can now handle file sizes over 2 GB.  Previously the
   compressed and uncompressed file sizes were being stored as signed longs
   instead of unsigned as the ZIP spec specifies.
 - Bug #981530: Fix UnboundLocalError in shutil.rmtree().  This affects
   the documented behavior: the function passed to the onerror()
   handler can now also be os.listdir.
@@ -134,7 +145,7 @@
 - Bug #1034496: Use -h instead of -soname for Solaris compatibility.
-- Patch #973204: Use -rpath instead of -R for runtime_library_dirs 
+- Patch #973204: Use -rpath instead of -R for runtime_library_dirs
   on Irix and True64.
 - Bug #978645: Modules/getpath.c now builds properly under --disable-framework

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