bug#57566: 13.1.4; Disappearing content when previewing inline math with LuaTeX

[Arash Esbati]

Ikumi Keita <ikumi@ikumi.que.jp> writes:

> Hi Michael,
>
>>>>>> "Braun, Michael" <braunm@mail.smu.edu> writes:
>> Here's a MWE:
>
>> \documentclass{standalone}
>> \begin{document}
>
>> AA $\alpha$ BB $\beta$ GG $\gamma$ DD $\Delta$.
>
>> \end{document}
>
>> Let's say I open this file and (preview-buffer). Then, I click on the
>> gamma symbol (which auto-reveals), edit the preview area to $\gamma +
>> 1$, and run (preview-at-point). The $\gamma+1$ renders correctly, but
>> everything up to, but not including, AA disappears. So all I see is
>> "AA <\gamma+1> DD <\Delta>" (where < ... > is the rendered math
>> expression).
>
>> The "$\alpha$ BB $\beta$ GG" is now hidden under the preview area for
>> <gamma+1>. I need to (preview-clearout-at-point) to get it all back.
>> It looks like when preview looks backwards, it is indeed extending
>> through all unmodified previews back to the beginning of the line, but
>> is showing only the rightmost preview that I edited.
>
> Thank you for the report. I can confirm the issue. It seems that the
> origin is the same as bug#54200[1]. Lualatex emits log message in
> slightly different format from the one of pdflatex.
>
> Unfortunately, the luatex developper isn't eager to fix this issue
> as you can read in [1]. I'm afraid that it won't be fixed in the near
> future. :-(
>
> You can try ad-hoc work around provided in [1], but note that
> 1. It isn't sure that the hard-coded value of 2 is valid for other
>    cases.
> 2. It breaks for other engines than lualatex.
>
> [1] https://debbugs.gnu.org/54200

In this case, AUCTeX relies on LuaTeX, so we can't fix this issue.  We
closed #54200 for the same reason, so I close this one as well.

Best, Arash