Re: GDB 12.0.90 available for testing

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 31 Mar 2022 10:48:18 +0100
> Cc: gdb-patches@sourceware.org, Andrew Burgess <aburgess@redhat.com>
> From: Pedro Alves <pedro@palves.net>
> 
> >>   https://sourceware.org/bugzilla/show_bug.cgi?id=29002
> > 
> > Ping!  The two issues described in this PR are IMO serious and should
> > be fixed before GDB 12.1 is released.  Could someone please respond to
> > what I wrote there, and propose how to fix this without adversely
> > affecting GNU/Linux (and possibly other non-Windows platforms)?
> 
> So from the bugzilla discussion, it sounds like calling setvbuf all the
> time is a bad idea.  So we should call it once for a given stream early
> on, just once.  That sounds reasonable to me.  However, the patch you
> attached in bugzilla doesn't seem to be doing that correctly:
> 
> 
> 836	  if (!done_once && !ISATTY (stream))
> 837	    {
> 838	      setbuf (stream, NULL);
> 839	      done_once = 1;
> 840	    }
> 836	
> 841	
> 
> because that will only do it once for all streams, and we need to do this
> once per stream.

The above was what we did in GDB 11 and before.

I'm okay with testing an alternative patch, or trying to write one
myself, but for the latter I need some guidance, as I'm not familiar
with how streams are managed in GDB.  Specifically, how do I "do this
once per stream"?  It would require some flag for each stream (in
'struct ui') or something?