Compilation error due to failed mainfile detection! for standalone files

[Rmano]

Description

After the last upgrade (of vimtex as well as of the operating system), I have often the following error on simple files:

this is with lalla.tex

\documentclass[border=10pt]{standalone}
\usepackage[siunitx, RPvoltages]{circuitikz}
  \begin{document}
  \begin{tikzpicture}[]
      \draw[red] (0,0) to[R] ++(2,0);
  \end{tikzpicture}
\end{document}

opened with vim -u ~/software/bugs/vimtex/minivimrc lalla.tex where the minivimrc is:

set nocompatible
let &rtp  = '~/.vim/plugged/vimtex,' . &rtp
let &rtp .= ',~/.vim/plugged/vimtex/after'
filetype plugin indent on
syntax enable

and ~/.latexmkrc

$pdflatex = 'pdflatex -synctex=1 %O %S';
$pdf_update_method = 0;
$dvi_mode = 0;
$pdf_mode = 1;
$preview_continuous_mode = 1;
$pdf_previewer = 'start evince';

push @generated_exts, "cb";
push @generated_exts, "cb2";
push @generated_exts, "spl";
push @generated_exts, "nav";
push @generated_exts, "snm";
push @generated_exts, "tdo";
push @generated_exts, "nmo";
push @generated_exts, "brf";
push @generated_exts, "nlg";
push @generated_exts, "nlo";
push @generated_exts, "nls";
push @generated_exts, "synctex.gz";
push @generated_exts, "tex.latexmain";
push @generated_exts, "run.xml";

That seems to happen only when I try to compile files with standalone class...

System info:
  OS: Ubuntu 22.04.1 LTS
  Vim version: VIM 8.2 (1-3995)
  Has clientserver: true
  Servername: undefined (vim started without --servername)

VimTeX project: lalla
  base: lalla.tex
  root: /home/romano/tmp
  tex: /home/romano/tmp/lalla.tex
  main parser: fallback current file
  document class: standalone
  packages: circuitikz
  compiler: latexmk
    engine: -pdf
    options:
      -verbose
      -file-line-error
      -synctex=1
      -interaction=nonstopmode
    callback: 1
    continuous: 1
    executable: latexmk
  viewer: General
  qf method: LaTeX logfile

[Rmano]

Hmmm.... not even this:

%! TeX root: /home/romano/tmp/lalla.tex
\documentclass[border=10pt]{standalone}
\usepackage[siunitx, RPvoltages]{circuitikz}
\begin{document}
\begin{tikzpicture}[]
    \draw (0,0) to[R] ++(2,0);
\end{tikzpicture}
\end{document}

works. Does it seem that the standalone class is somehow marked as "never the main file"? Or I have a broken installation somehow?

[lervag]

Yes, sorry, I've made the main file detection more strict. And it seems it is clearly also faulty right now. Sorry! I'll try and fix asap!

[lervag]

Btw, notice that the tex root specifier requires an equal sign, not a colon, i.e. !% TeX root =. That's why your last example didn't work. Perhaps I should allow both?

[lervag]

I believe the problem should be solved now, please test.

[lervag]

And sorry about the inconvenience!

[Rmano]

Perfect, it works now! No problem, things happen.

About the = or : my fault, no need to change anything!

[lervag]

Perfect, it works now! No problem, things happen.

Good to hear!

About the = or : my fault, no need to change anything!

Well, I did anyway. Didn't see a reason why colon should not work here.

[Rmano]

Well, I did anyway. Didn't see a reason why colon should not work here.

Ok, nice. One suggestion/question: is there a way to say "this file is the root file"? Without having to explicitly use the file name? (Maybe a %TeX root : . syntax? (Didn't try, maybe it works already)

[lervag]

If the file is named myfile.tex, then %! TeX root: myfile.tex should do the trick. But: Why would you want this? It should essentially never be necessary?

[Rmano]

If the file is named myfile.tex, then %! TeX root: myfile.tex should do the trick. But: Why would you want this? It should essentially never be necessary?

You probably are right. I was thinking about compiling plain TeX files (but it seems that it is not working anyway, probably a latexmk limitation).

The problem is that if you have %! TeX root: myfile.tex and you rename the file, you have also to edit it...

[lervag]

Yes, that's true. But IMHO, we are now adressing "non issues"; or, at least, if you feel strongly about this, I would be happy to have a more concrete example where this would be useful?