auto-pst-pdf and pdfpages became incompatible?

Question

As I'm obviously ignorant with regard to some well-intended advices, I ran into a compilation error after updating my MiKTeX distribution after two or three months. I was able to track the error down to the following MNWE:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{auto-pst-pdf}
\usepackage{pdfpages}
\begin{document}
\includepdf{example-image-a.pdf}
\begin{figure}
    \includegraphics{example-image-b.eps}
\end{figure}
\end{document}

Compiling using pdflatex --shell-escape mwe.tex will show compilation errors during the auto-pst-pdf stage. mwe-autopp.log reads somewhat like:

[...]
File: example-image-b.eps Graphic file (type eps)
<example-image-b.eps>
Preview: Tightpage -39321600 -39321600 39321600 39321600
! You can't use `\prevdepth' in horizontal mode.
\nointerlineskip ->\prevdepth 
                              -\@m \p@ 
l.13    \includegraphics{example-image-b.eps}
Sorry, but I'm not programmed to handle this case;
I'll just pretend that you didn't ask for it.
If you're in the wrong mode, you might be able to
return to the right one by typing I}' orI$' or `I\par'.
! Missing $ inserted.
<inserted text> 
                $
l.13    \includegraphics{example-image-b.eps}
[...]

Compilation will run fine when either the \includepdf line or the figure environment are commented out, respectively. Could you please advice me on how to fix this one...? Thanks a lot!

/edit In response to comments by @Marijn and @Ulrike Fischer:

You are right, my MNWE was not chosen very cleverly! As a matter of fact, I also need the chemnum package in my real-world example to replace strings within the eps file. This method does need the auto-pst-pdf package and the --shell-escape option for pdflatex as far as I know. Let me slightly expand the example from above:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{auto-pst-pdf}
\usepackage{pdfpages}
\usepackage{chemnum}
\begin{document}
\includepdf{example-image-a.pdf}
\begin{figure}
    \replacecmpd[tag=benzene]{benzene}
    \includegraphics{benzene.eps}
\end{figure}
\end{document}

I've put the contents of benzene.eps to Pastebin: click.

Answer 1

miktex hasn't the newest eso-pic yet, it still use eso-pic 2020/09/27 v2.0i eso-pic.

The problem with this version is that it adds material starting with \nointerlineskip in the shipout/before hook, and due to the changes in the shipout routine in LaTeX this gets into the preview code in horizontal mode and harms there.

\__hook shipout/before ->\nointerlineskip \AtBeginShipoutUpperLeft {\put (0,\Le
nToUnit {\ESO@yoffsetI }){\ESO@HookIIIBG \ESO@HookIBG \ESO@HookIIBG \global \le
t \ESO@HookIIBG \@empty }}\AtBeginShipoutUpperLeftForeground {\put (0,\LenToUni
t {\ESO@yoffsetI }){\ESO@HookIFG \ESO@HookIIFG \ESO@HookIIIFG \global \let \ESO
@HookIIFG \@empty }}\PLS@AtBeginShipout \__hook_next shipout/before
\nointerlineskip ->\prevdepth -@m \p@ 
! You can't use `\prevdepth' in horizontal mode.

With a newer eso-pic the document compiles for me.

I opened an issue at the miktex issue tracker: https://github.com/MiKTeX/miktex-packaging/issues/211.

But be aware that preview and pst-pdf do some low-level shipout manipulations, and the changes in LaTeX affects them. For example preview is currently not compatible with hyperref: https://lists.gnu.org/archive/html/bug-auctex/2020-11/msg00000.html.