bug#72392: 30.0.50; Wrong `next-line` behavior

[Eli Zaretskii <eliz@gnu.org>]

> Cc: monnier@iro.umontreal.ca
> Date: Wed, 31 Jul 2024 03:43:20 -0400
> From:  Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> - Apply the `smerge-mode.patch` below to Emacs's` master` (and
>   recompile `smerge-mode.el`).
> - Open the short diff file below with:
> 
>     emacs -Q --eval '(setq-default word-wrap t diff-font-lock-prettify t)' \
>           .../bug-weird-next-line.diff
> 
> - In my case, when this opens there's a "word wrap" just before "This"
>   and just before "\id{seg}" (on the 4th and 5th lines, resp).
>   If that's not the case for you, resize your frame so that this is
>   the case.
> 
> - Do `C-n` a few times.

Any hope of a simpler recipe, which would not require patching Emacs?
Cannot you just post the contents of the problematic buffer and the
non-default settings to use to reproduce the problem?

The bug is probably somewhere in vertical-motion or in line-move and
its subroutines, but a simpler recipe will make the investigation less
painful.

TIA