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.
the same object to be collected by the cyclic GC support if they are
only referenced by a cycle. If the weakref being collected was one of
the weakrefs without callbacks, some local variables for the
constructor became invalid and have to be re-computed.
The test caused a segfault under a debug build without the fix applied.
Also SF patch 843455.
This is a critical bugfix, backported from 2.4 development.
I don't intend to backport beyond 2.3 maint. The bugs this fixes
have been there since weakrefs were introduced.
the left-hand operand may not be the proxy in all cases. If it isn't,
we end up doing two things: a) unwrapping something that isn't a
PyWeakReference (later resulting in a core dump) and b) passing a
proxy as the right-hand operand anyway, even though that can't be
handled by the actual handler (maybe eventually causing a core dump).
This is fixed by always unwrapping all the proxies involved before
passing anything to the actual handler.
