Re: RFC: clear quit_flag in quit, not throw_exception

[Tom Tromey <tromey@redhat.com>]

>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:

Pedro> If the unrelated exception/error unwinds things all the way up to
Pedro> the top prompt, managing to bypass all QUIT calls, then we'll end
Pedro> up with a dangling quit until the next command it entered
Pedro> (resulting in a spurious, delayed "Quit"), it seems to me.  If
Pedro> that analysis is correct, maybe we should also clear or handle
Pedro> these somehow somewhere near the top loop?

Thanks for noticing this.

I looked into the problem in more detail, and I think it is a crazy
morass.

The quit_flag part is all solvable.  Maybe I will tackle it.

However, the immediate_quit part is really quite bad.  I started by
changing the current places that set and clear immediate_quit to use a
cleanup instead.  However, remote_start_remote remains a big problem --
it is just wrong.  I think a fix here would be to only set and clear
immediate_quit around I/O primitives.  But, finding all those and
applying the change is troublesome.

One idea I had was that maybe we could simply not have immediate_quit,
but instead rely on EINTR and sprinkle more QUIT calls around.  In my
initial experiment, this didn't seem to work, but I haven't gone back
yet to understand why.

Maybe someone else has a more workable idea.

Tom