bug#73863: 30.0.91; Unexpected cursor movement with flymake-show-diagnostics-at-end-of-line

[Eli Zaretskii <eliz@gnu.org>]

> From: Romain Ouabdelkader <romain.ouabdelkader@gmail.com>
> Date: Thu, 31 Oct 2024 00:57:20 +0100
> Cc: sbaugh@janestreet.com, joaotavora@gmail.com, 73863@debbugs.gnu.org
> 
> I don't use neovim but from what I have seen from screenshots, the diagnostics are truncated if they are
> larger than the window.

Is this really better than the minor annoyance we have now?

If it's better, we could add a feature whereby an overlay can request
its text to be truncated at the window edge, even if truncate-lines is
not in effect.  But good UI practices would then require us to have a
tooltip with the full text on the overlay, I think, since otherwise
the user will not be able to see the full text, and the important part
might be at the end.

> Maybe there could be a way to have diagnostics truncated by default and only show the full diagnostics
> when the cursor is in the error line. But I'm not sure how that would work.

This is much harder to implement (unless Flymake itself implements
this, i.e., it truncates the overlay text when point is on another
line).  It will also cause an annoying vertical movement of the rest
of buffer text when cursor moves.

> For myself, I'll use sideline (https://github.com/emacs-sideline/sideline) instead of
> flymake-show-diagnostics-at-end-of-line. 

It is not clear to me what that does, but it looks like it displays
the diagnostic on a different screen line, not on the line to which
the diagnostic belongs?

> After thinking about it, I actually prefer to only view diagnostics for the current line (which is what sideline can
> do)

That is strange to hear, because it doesn't allow to have an overview
of the diagnostics at a glance.

Spencer, any comments or suggestions?