[PING^2][PATCH][PR gdb/21690] Fix interruption of command history search

[Andrew Burgess]

* Hannes Domani <ssbssa@yahoo.de> [2020-06-08 14:58:50 +0000]:

>  Am Montag, 8. Juni 2020, 16:41:32 MESZ hat Andrew Burgess <andrew.burgess@embecosm.com> Folgendes geschrieben:
> 
> > * Hannes Domani via Gdb-patches <gdb-patches@sourceware.org> [2020-06-08 11:51:07 +0000]:
> >
> > > Ping.
> > >
> > > Am Freitag, 15. Mai 2020, 11:00:41 MESZ hat Hannes Domani via Gdb-patches <gdb-patches@sourceware.org> Folgendes geschrieben:
> > >
> > > > Am Samstag, 25. April 2020, 19:17:34 MESZ hat Hannes Domani via Gdb-patches <gdb-patches@sourceware.org> Folgendes geschrieben:
> > > >
> > > > Ping.
> > > >
> > > > > If you press Ctrl-C during an incremental search of the readline history, the
> > > > > prompt is reset, but readline is still in the incremental search mode.
> > > > >
> > > > > The call of rl_callback_sigcleanup cleans up the internal readline state, and
> > > > > disables the incremental search mode.
> >
> > I didn't look into the implementation of this, but something seems a
> > little odd, though I don't know if this is just my machine setup....
> >
> > I start a GDB session, and do this:
> >
> >   (gdb) echo hello\n
> >   hello
> >
> > At this point I start a reverse search, so I type:
> >
> >   <ctrl+r>
> >   echo
> >   <ctrl+c>
> >
> > Now I'm left in this situation:
> >
> >   (gdb) echo hello\n
> >         ^
> >         '-- Prompt is here.
> >
> > So, whatever I was in the process of finding when I hit Ctrl+C is left
> > on my prompt line in an editable state.
> >
> > This is different from the behaviour I see in, for example, bash,
> > where when I Ctrl+C the reverse search is aborted and I'm dropped back
> > to an empty prompt.
> >
> > Which behaviour do you see?
> 
> This is the behaviour I also see with this patch applied.
> 
> 
> > Which behaviour do you expect to see?
> 
> I didn't compare with anything else, so my expectation was just that it
> shouldn't be in this weird state where the prompt is empty, but readline
> actually thinks it's still in the reverse search.

I think we should end up back at the empty prompt.  That certainly
feels more natural after a Ctrl+C (to me anyway).

Thanks,
Andrew