Re: read_char() does not detect, handle special-event-map buffer changes

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

> in a separate terminal.  Move focus back to Emacs before the signal goes
> out.  Hit `q' in the new buffer and Emacs will complain about "*foo*"
> being read-only.  The second time you hit `q', Emacs will exit view mode
> and bury the buffer.

I think this is a known problem: the set of active keymaps is determined
at the end of the previous command, so any change performed via
something like a special-event-map binding or a process-filter will bump
into this problem (you don't even need to switch-to-buffer, just
enabling view-mode is sufficient).

It's a bug: we should instead wait until the first key is pressed
before figuring out the active keymaps.
Problem is, this bug is in read_key_sequence, which is a pretty
scary function.

In the mean time, you can work around the bug by adding to
unread-command-event (from your sigusr1-handler) a dummy event that is
bound in global-map to something like `ignore'.


        Stefan