Strange behaviour using center, tcolorbox, listings and enumerate

Question

I have a problem compiling the following minimal example:

\documentclass{article}
\usepackage{listings}
\usepackage{tcolorbox}

\begin{document}
\begin{center}
    \begin{tcolorbox}
        \begin{lstlisting}
            alert(123);
        \end{lstlisting}

        boom

        \begin{enumerate}
            \item one
            \item two
        \end{enumerate}
    \end{tcolorbox}
\end{center}
\end{document}

I cannot reduce anything and don't know if the problem is dedicated to listings, tcolorbox, enumerate or center. (maybe all of them together)

The error is

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.15 ^^I^^I^^I\item o
                     ne

which is (like most LaTeX errors) not very useful…

Answer 1

The \begin{center} confuses tcolorbox besides adding undesirable additional vertical space. Either add \leavevmode before \begin{tcolorbox} or better use {\centering.... } as suggested by @PeterGrill in a comment.

\documentclass{article}
\usepackage{listings}
\usepackage{tcolorbox}

\begin{document}

\begin{center}\leavevmode
\begin{tcolorbox}
    \begin{lstlisting}
        alert(123);
    \end{lstlisting}
    boom
    \begin{enumerate}
        \item one
        \item two
    \end{enumerate}
\end{tcolorbox}
\end{center}

\end{document}

Answer 2

Update: removal of borders.

It seems to me that from your own response to your problem that you don't want the listing to be in a visible box. And as with tcolorbox, everything is configurable, just set it up.

• With the skin=empty parameter, nothing is drawn at all: so there is no border (see page 237).
• With the parameter lowerbox=ignored not to display the lower part of the box (see p 24).

It is therefore also possible to set the distances between the content of the listing and the rest of the box, but i did not do.

\documentclass{article}
%\usepackage{listings}
\usepackage[most]{tcolorbox}

\begin{document}
\begin{center}
    \begin{tcolorbox}
        \begin{tcblisting}{skin=empty,lowerbox=ignored}
            alert(123);
        \end{tcblisting}

        boom

        \begin{enumerate}
            \item one
            \item two
        \end{enumerate}
    \end{tcolorbox}
\end{center}

\end{document}

Old answer:

It is possible to use the dispListing environment of the tcolorbox documentation library (see page 465 of the 4.14 manual).

\documentclass{article}
%\usepackage{listings}
\usepackage[most]{tcolorbox}
\tcbuselibrary{documentation}
\begin{document}
\begin{center}
    \begin{tcolorbox}
        \begin{dispListing}
            alert(123);
        \end{dispListing}

        boom

        \begin{enumerate}
            \item one
            \item two
        \end{enumerate}
    \end{tcolorbox}
\end{center}
\end{document}

Translated with www.DeepL.com/Translator

Answer 3

Thank's to @AboAmmar , @PeterGrill and @egreg who managed to find out the source of the error namely the center environment.

To get the the tcolorbox centered we can use its center option:

\documentclass{article}
\usepackage{listings}
\usepackage{tcolorbox}

\begin{document}

\noindent\hrulefill % this rule is added to show that the box is actually centered

    \begin{tcolorbox}[width=0.75\linewidth,center]
        \begin{lstlisting}
            alert(123);
        \end{lstlisting}

        boom

        \begin{enumerate}
            \item one
            \item two
        \end{enumerate}
    \end{tcolorbox}

    \noindent\hrulefill 


\end{document}