Bug in the filename handling that results in writing to the wrong file name if it contains spaces

[FrankMittelbach]

Brief outline of the bug

In certain situation, e.g., when the document below is processed twice then the file written is not properly quoted so that a file with spaces is opening the wrong file for output.

Minimal example showing the bug

\RequirePackage{latexbug}       % <--should be always the first line (see CONTRIBUTING)!
\documentclass{article}

\begin{document}

\begin{filecontents}[force]{file here.txt}
  yes
\end{filecontents}

\newcommand\myname{"file here.txt"}
\sbox0{\IfFileExists{\myname}{\typeout{3: yes}}{\typeout{3: no}}}
\showthe\wd0

\end{document}

[FrankMittelbach]

gone to CTAN