that are suspended outside of any try/except/finally blocks to be
garbage collected even if they are part of a cycle. Generators that
suspend inside of an active try/except or try/finally block (including
those created by a ``with`` statement) are still not GC-able if they
are part of a cycle, however.
added message attribute compared to the previous version of Exception. It is
also a new-style class, making all exceptions now new-style. KeyboardInterrupt
and SystemExit inherit from BaseException directly. String exceptions now
raise DeprecationWarning.
Applies patch 1104669, and closes bugs 1012952 and 518846.
* Allow the 3rd argument to generator.throw() to be None.
The 'raise' statement does the same, and anyway it follows the
general policy that optional arguments of built-ins should, when
reasonable, have a default value specifiable from Python.
was never called during interpreter shutdown GC, so the f_back!=NULL
assertion was correct. Now that generators get close()d during GC,
the assertion was being triggered because the generator close() was being
called as the top-level frame. However, nothing actually is broken by
this; it's just that the condition was unexpected in previous Python
versions.