bug#27427: 26.0.50; Native line numbers lead to display error in company-mode popup

[Eli Zaretskii]

> Cc: alexanderm@web.de, 27427@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Thu, 29 Jun 2017 04:34:16 +0300
> 
> On 6/28/17 7:48 PM, Eli Zaretskii wrote:
> 
> > Dmitry, can you tell why the popup overlay is a single overlay with a
> > single multiline string, and not a series of overlays, one each for
> > every line shown in the popup?  I assume this caused or could cause
> > more serious problems than the current implementation, but what
> > problems were those?
> 
> Different tradeoffs, some different problems, and a lot of common ones 
> (like text scaling, images, character widths, etc).

But all of these are not relevant to TTY frames, right?

> How would that help with the current issue?

Martin is trying very hard to come up with a method to overcome the
fact that Emacs cannot display "rectangular" overlay strings.
Breaking the string into several one-line strings and putting their
overlays at the appropriate buffer positions would solve this problem.

> One-line-per-overlay approach will always work worse in display-heavy 
> buffers, for instance. Like the 'M-x report-emacs-bug' one. 

Why would it work worse in that case?