Dvilualatex made for? Strange output

Question

I might be asking something stupid, but why does pushing mwe.tex containing

\documentclass{article}
\pagestyle{empty}
\begin{document}
Text
\end{document}

through dvilualatex mwe && dvips mwe lead to the output

both in mwe.dvi and mwe.ps ?

I thought that dvilualatex is there for generating a DVI file via luatex instead of latex, isn't it?

By the way, dvips prints a strange font-not-found error message to the console although the font file exists:

$ dvips mwe && ls -la /usr/share/texmf/fonts/opentype/public/lm/lmroman10-regular.otf
This is dvips(k) 2021.1 (TeX Live 2022/dev)  Copyright 2021 Radical Eye Software (www.radicaleye.com)
' LuaTeX output 2022.03.07:1640' -> mwe.ps
dvips: Font [/usr/share/texmf/fonts/opentype/public/lm/lmroman10-regular.otf] not found; using cmr10
</usr/share/texlive/texmf-dist/fonts/pk/ljfour/public/cm/dpi600/cmr10.pk>
dvips: Checksum mismatch in font [/usr/share/texmf/fonts/opentype/public/lm/lmroman10-regular.otf]
</usr/share/texlive/texmf-dist/dvips/base/tex.pro>
</usr/share/texlive/texmf-dist/dvips/l3backend/l3backend-dvips.pro>
</usr/share/texlive/texmf-dist/dvips/base/special.pro>. [1] 
-rw-r--r-- 1 root root 111536  7. Okt 2009  /usr/share/texmf/fonts/opentype/public/lm/lmroman10-regular.otf

We use

$ dvilualatex --version
This is LuaTeX, Version 1.14.0 (TeX Live 2022/dev/Debian)
$ dvips --version
This is dvips(k) 2021.1 (TeX Live 2022/dev)  Copyright 2021 Radical Eye Software
kpathsea version 6.3.4/dev

Answer 1

While it is possible to do some things it is more or less true that dviluatex if using OpenType fonts will write a dvi file that no dvi driver can use. (dvipdfmx has some support for this in recent releases, but that doesn't help if the aim is to get PostScript).

In the dvips output that you show, you see it failing on the Unicode OpenType Latin Modern, substituting its error fallback cmr10 pk bitmaps and hoping for the best.....

If you use a 7 or 8 bit classic Tex font, the resulting dvi file is usable eg

\documentclass{article}

\usepackage[T1]{fontenc}

\begin{document}

Hello world

\directlua{tex.write('look Lua is here!')}

\end{document}

has a clean run in dvilualatex

This is LuaTeX, Version 1.15.0 (TeX Live 2022) 
 restricted system commands enabled.
(./cc059.tex
LaTeX2e <2021-11-15> patch level 1
 L3 programming layer <2022-02-24>
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/article.cls
Document Class: article 2021/10/04 v1.4n Standard LaTeX document class
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/fontenc.sty
(/usr/local/texlive/2022/texmf-dist/tex/latex/lm/t1lmr.fd))
(/home/davidc/texmf/tex/latex/l3backend/l3backend-dvips.def) (./cc059.aux)
(/usr/local/texlive/2022/texmf-dist/tex/latex/base/ts1cmr.fd) [1] (./cc059.aux)
)
 406 words of node memory still in use:
   3 hlist, 1 vlist, 1 rule, 2 glue, 3 kern, 1 glyph, 4 attribute, 48 glue_spec
, 4 attribute_list, 1 write nodes
   avail lists: 2:33,3:11,4:2,5:24,6:6,7:139,9:36
Output written on cc059.dvi (1 page, 296 bytes).
Transcript written on cc059.log.

and dvips is happy

$ dvips cc059
This is dvips(k) 2022.1 (TeX Live 2022)  Copyright 2022 Radical Eye Software (www.radicaleye.com)
' LuaTeX output 2022.03.07:1636' -> cc059.ps
</usr/local/texlive/2022/texmf-dist/dvips/base/tex.pro>
</home/davidc/texmf/dvips/l3backend/l3backend-dvips.pro>
</usr/local/texlive/2022/texmf-dist/fonts/enc/dvips/lm/lm-ec.enc>
</usr/local/texlive/2022/texmf-dist/dvips/base/texps.pro>
</usr/local/texlive/2022/texmf-dist/dvips/base/special.pro>. 
</usr/local/texlive/2022/texmf-dist/fonts/type1/public/lm/lmr10.pfb>[1]

and the resulting PostScript uses scalable type 1 Latin Modern: