\documentclass{article}
\usepackage{graphics}
\usepackage{grffile}
\usepackage{mwe}
\begin{document}
\includegraphics{example-image}
\end{document}
I can compile the above given document with pdflatex but not lualatex anymore. I am pretty sure this issue is due to a recent update of my TeX Live 2019 installation from today or a few days ago.
This is LuaTeX, Version 1.10.0 (TeX Live 2019)
restricted system commands enabled.
(./demo.tex
LaTeX2e <2019-10-01> patch level 1
luaotfload | main : initialization completed in 0.208 seconds
(/usr/local/texlive/2019/texmf-dist/tex/latex/base/article.cls
Document Class: article 2019/08/27 v1.4j Standard LaTeX document class
(/usr/local/texlive/2019/texmf-dist/tex/latex/base/size10.clo))
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics-def/luatex.def))
(/usr/local/texlive/2019/texmf-dist/tex/latex/oberdiek/grffile.sty
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/ifpdf.sty)
(/usr/local/texlive/2019/texmf-dist/tex/generic/ifxetex/ifxetex.sty)
(/usr/local/texlive/2019/texmf-dist/tex/latex/oberdiek/kvoptions.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/ltxcmds.sty)
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/kvsetkeys.sty
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/infwarerr.sty)
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/etexcmds.sty
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/ifluatex.sty))))
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/pdftexcmds.sty))
(/usr/local/texlive/2019/texmf-dist/tex/latex/mwe/mwe.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/graphics/graphicx.sty)
(/usr/local/texlive/2019/texmf-dist/tex/latex/lipsum/lipsum.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/l3kernel/expl3-code.tex
(/usr/local/texlive/2019/texmf-dist/tex/latex/l3kernel/l3deprecation.def))
(/usr/local/texlive/2019/texmf-dist/tex/latex/l3backend/l3backend-pdfmode.def))
(/usr/local/texlive/2019/texmf-dist/tex/latex/l3packages/xparse/xparse.sty)
(/usr/local/texlive/2019/texmf-dist/tex/latex/lipsum/lipsum.ltd.tex))
(/usr/local/texlive/2019/texmf-dist/tex/latex/blindtext/blindtext.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/tools/xspace.sty))) (./demo.aux)
(/usr/local/texlive/2019/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
) (/usr/local/texlive/2019/texmf-dist/tex/latex/oberdiek/epstopdf-base.sty
(/usr/local/texlive/2019/texmf-dist/tex/latex/oberdiek/grfext.sty
(/usr/local/texlive/2019/texmf-dist/tex/generic/oberdiek/kvdefinekeys.sty))
(/usr/local/texlive/2019/texmf-dist/tex/latex/latexconfig/epstopdf-sys.cfg))
! LaTeX Error: File `example-image' not found.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.7 \includegraphics{example-image}
? ^D
! Emergency stop.
...
l.7 \includegraphics{example-image}
411 words of node memory still in use:
3 hlist, 1 rule, 1 local_par, 1 dir, 1 glue, 3 kern, 1 glyph, 5 attribute, 4
8 glue_spec, 5 attribute_list, 1 temp, 2 if_stack, 1 write nodes
avail lists: 2:10,3:3,4:1,5:3,7:1,9:1
! ==> Fatal error occurred, no output PDF file produced!
Transcript written on demo.log.
If I run with a picture in a subdirectory I get:
LaTeX Warning: File `pics/1-uniform_7_p6_[2].pdf' not found on input line 7.
! error: (file "pics/""1-uniform_7_p6_[2]".pdf) (pdf backend): cannot find ima
ge file '"pics/""1-uniform_7_p6_[2]".pdf'
! ==> Fatal error occurred, no output PDF file produced!
There is something weird with the use of quotes
"pics/""1-uniform_7_p6_[2]".pdf
When I remove the package grffile, lualatex works again.
If someone one wants to reproduce it, an absolute up-to-date TeX Live 2019 is probably necessary. (In case you are writing a thesis, you might not want to update your TeX Live installation until you have submitted your thesis. A lesson I learn again and again.)