[Python-Dev] Eliminating f_tstate

["Martin v. Löwis"]

Bug #1579370 reports a crash when accessing the thread state of
a terminated thread, when releasing a generator object.

In analysing the problem, I found that f_tstate doesn't have much
utility: it is used in very few places, and in these places, it
might be as good or better to use the *current* thread state
(rather than the frame's thread state); in some (most?) of these
places, the current thread should be identical to the frame's
thread, anyway.

So I would like to propose that the f_tstate member is removed
from the frame object.

For Python 2.5, for compatibility, it probably has to remain
where it is, and only PyTraceBack_Here should stop using it.
As a consequence, a generator .send() makes exceptions
occur in the current thread, not in the thread where the
generator was created.

What do you think?

Regards,
Martin