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

[Eli Zaretskii <eliz@gnu.org>]

> From: João Távora <joaotavora@gmail.com>
> Date: Sun, 20 Oct 2024 12:38:33 +0100
> Cc: sbaugh@janestreet.com, romain.ouabdelkader@gmail.com, 
> 	73863@debbugs.gnu.org
> 
> On Sun, Oct 20, 2024 at 12:22 PM Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > When the diagnostic overlay wraps to the next screen line, it is
> > strange to see the cursor at the beginning of the diagnostic after
> > C-n, since users generally expect C-n to move to the next screen line.
> 
> That may be so, and probably it is so. But I'd make sure to keep the
> current behaviour (or at least unsurprising behaviour) when the
> diagnostic(s) overlay (overlays?) _doesn't_ (don't?) wrap to the next
> screen line.

That would mean a non-trivial code in flymake.el, because it would
need to decide in advance whether the diagnostic will fit on the same
screen line.  Moreover, if the user then makes the window wider or
narrower, the cursor will jump between two screen positions, something
that I think is highly undesirable (and will look like a bug).