bug#32502: 27.0.50; Tramp; C-g during asynchronous remote find-file kills Emacs

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Cc: gazally@runbox.com,  32502@debbugs.gnu.org
> Date: Sat, 25 Aug 2018 12:53:02 +0200
> 
> > Michael, unless I'm missing something, it sounds like Tramp signals
> > the main thread in this scenario.  (current_thread->error_symbol is
> > only set by thread-signal.)  Is that really necessary?  If so, can you
> > describe why you needed to signal the main thread, while it was
> > waiting for input?
> 
> Tramp propagates all signals to the main thread, otherwise they are not
> visible.

Is that wise?  It means that if a user is doing something in the main
thread while the Tramp threads run asynchronously, the user's program
will/might error out.

> However, if we apply this I don't know how to quit (let's say) 250
> threads. One quit signal is good for one thread only. I believe we need
> also a mechanism to quit many threads at once.

I think we should simply make thread-signal a no-op when it signals
the main thread during the time the main thread is waiting for input.