Subject: Re: bug#25246: 25.1.90; Buffer not responsible with overlay at buffer end.

From: "Stefan-W. Hahn" <[email-masked]>
Date: Fri, 23 Dec 2016 14:36:47 +0100

Mail von Eli Zaretskii, Fri, 23 Dec 2016 at 13:08:57 +0200:

Hello,

> If the change below, when applied to the master branch, gives good
> results, I will install it.

tried this on Linux and Windows. Works really good.

> The results as I see after this change are not ideal (you cannot see
> the entire overlay string, unless you manually hscroll the window with
> "C-x >", and the cursor at EOB is not visible).  But at least the loop

That is no problem, because the overlay moves if compilation proceeds and
the compilation buffer gets more content.

The problem only arises if a single line of output in compilation buffer was
bigger then the screen width (and I have truncates-lines set to t) and had
no LF. In all other cases there was no problem. I saw this just now,,
because our production environment is producing such long lines since not so
long time.

> is avoided, AFAICT, and there's only one "blink" of incorrect display.
> Is this satisfactory enough to install this simple change?

As said. It works very well.

Thank you.

With kind regards,
Stefan

> 
> Thanks.
> 
> diff --git a/src/xdisp.c b/src/xdisp.c
> index ad0b968..37ca81d 100644
> --- a/src/xdisp.c
> +++ b/src/xdisp.c
> @@ -13049,6 +13049,17 @@ hscroll_window_tree (Lisp_Object window)
>  	      init_to_row_start (&it, w, cursor_row);
>  	      it.last_visible_x = INFINITY;
>  	      move_it_in_display_line_to (&it, pt, -1, MOVE_TO_POS);
> +	      /* If the line ends in an overlay string with a newline,
> +		 we might infloop, because displaying the window will
> +		 want to put the cursor after the overlay, i.e. at X
> +		 coordinate of zero on the next screen line.  So we
> +		 use the buffer position prior to the overlay string
> +		 instead.  */
> +	      if (it.method == GET_FROM_STRING && pt > 1)
> +		{
> +		  init_to_row_start (&it, w, cursor_row);
> +		  move_it_in_display_line_to (&it, pt - 1, -1, MOVE_TO_POS);
> +		}
>  	      current_buffer = saved_current_buffer;
>  
>  	      /* Position cursor in window.  */
> 

-- 
Stefan-W. Hahn                          It is easy to make things.
                                        It is hard to make things simple.