How to force LaTeX to error when an \include file is missing/misspelled?

Question

The only file which was meant to be compiled in my Main.tex was specified by the following line:

\include{transformtaion}

It was compiled without any error using the following command:

pdflatex -synctex=1 -interaction=nonstopmode Main.tex

However, the generated PDF file was empty. After investing a large amount of time, I learned that the problem is with misspelling of the file, i.e. transformtaion instead of transformation.
The question is how to force the compilation process to give a compile-time error which indicates the misspelling problem.

Answer 1

It is a (maybe not so great) feature of \include to just tell you on the terminal that the file does not exist. You get a one-liner like this:

No file transformtaion.tex.

which is quite hard to spot if you're not looking for it.

Redefining the internals of \include is not advisable, so you can use the include hooks to explicitly check for the existence of the file, and error accordingly:

\documentclass{article}

\makeatletter
\def\mkfilename#1{%
  \if\relax\detokenize\expandafter{#1}\relax\else#1/\fi}
\AddToHook{include/before}%
  {\IfFileExists{\mkfilename\CurrentFilePath\CurrentFile}{}
     {\GenericError{}{Error: File \mkfilename\CurrentFilePath\CurrentFile.tex not found!}{\@gobble}{}}}
\makeatother

\begin{document}
\include{transformtaion}
\end{document}

then you'll see an error:

! Error: File transformtaion.tex not found!.

Type  H <return>  for immediate help.
 ...

l.15 \include{transformtaion}

?

---

In older releases (before 2020-10-01), without the built-in support for include hooks, you can use filehook and currfile:

\documentclass{article}

\usepackage{filehook}
\usepackage{currfile}
\makeatletter
\AtBeginOfIncludes
  {\IfFileExists{\currfiledir\currfilebase.tex}{}
     {\GenericError{}{Error: File \currfiledir\currfilebase.tex not found!}{\@gobble}{}}}
\makeatother

\begin{document}
\include{transformtaion}
\end{document}