Re: Fixes to X11_waitforinput()

[Ethan A M. <me...@uw...>]

On Saturday, 14 March 2020 23:12:24 PDT Dima Kogan wrote:
> Hi.
> 
> I've been working on fixing broken "pause mouse close" behavior on the
> x11 terminal while x-forwarding. This is
> 
>   https://sourceforge.net/p/gnuplot/bugs/2208/
> 
> In the process I discovered that I already encountered weirdness in this
> area previously:
> 
>   https://sourceforge.net/p/gnuplot/mailman/message/36440354/
> 
> I just fixed all the issues, I think. These are in 2 patches on this
> branch:
> 
>   https://github.com/dkogan/gnuplot/commits/fixed-x11-waitforinput
> 
> The first patch improves diagnostic printing in this area. Instead of
> printing enums as NUMBERS, it prints the enum NAMES. This is infinitely
> more useful.
> 
> The second patch contains the actual fixes. It looks more invasive than
> it is. 99% of the modifications are in X11_waitforinput(). And much of
> it is indentation.
> 
> There were several issues, all of them caused by hoaky input
> multiplexing. I'm attaching two very simple gnuplot scripts that tickled
> the bug. To observe the problems you need to slow down the X connection
> by ssh-ing to any server, and trying to plot through x-forwarding.
> Before any of the fixes this would happen:
> 
>     $ gnuplot < mild.pause.mouse.close.broken.gp
> 
>     gnuplot> ause mouse close
>              ^
>              line 0: invalid command
> 

> [...snip...]

> It works for me so far, but this is an error-prone area. Can somebody
> take a look? The new approach is much better, I think, but more testing
> would be good.

It has been a long time since I looked at the x11 input multiplexing code
but I remember that it was a mess and many observed problems were
dealt with by slapping a special case in rather than rethinking the design.
So yes, a re-write is a good thing.

Your revised code works well in all the tests that I ran, but I am sure that
there are people with use-cases I didn't test.  If you are reading this and
find a problem with the new code, let us know.

Anyhow, I've imported your fixes into the main code repository.
Keep up the good work. 
	
	Ethan