Re: MI commands with --thread (--frame?) do not preserve user selected thread / frame

[Jan Vrany <jan.vrany@fit.cvut.cz>]

On Wed, 2019-06-19 at 11:54 -0400, Simon Marchi wrote:
> On 2019-06-19 11:10 a.m., Jan Vrany wrote:
> > On Wed, 2019-06-19 at 11:53 +0100, Jan Vrany wrote:
> > > Hi, 
> > > 
> > > I was debugging a multithreaded program and realized that using --thread option to
> > > verious MI command silently changes user selected thread - here's an example using
> > > separate UI and CLI chahhel (tested on commit 6f5601c4d0)
> > > 
> > > 
> > ...
> > > 
> > > As you can see, there was no `frame`, `thread`, `-select-frame` or `-thread-select` command between
> > > first and second info thread / frame commands on CLI, yet the selected thread / frame changed (silently).
> > > 
> > > Is this intended behavior? If so what's the rationale?
> 
> No, this is indeed a known bug:
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=20684
> 

Ah, I see. 

> > 
> So it seems to work (at least for a simple case, there might be some edge cases I don't recall).  I
> think that the CLI and MI events about the thread change should not appear though, since the goal is
> to make it appear as if there is no user selection changes.

I agree, the event should not be emitted. This was just a quick hack whether 
it'd help in my case. If you think this is an acceptable way of "fixing" it,
I'm happy to improve this patch and submit. 

Jan