xsim 和 TeXLive 2020 出现缺失项目错误

Question

我最近从 TeXLive 2019 更新到了 TeXLive 2020。将代码从这链接（仅稍作修改）不再起作用。它终止并显示以下错误：

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

完整 mwe：

\documentclass{scrartcl}

\usepackage{xsim}
\usepackage{environ}
\usepackage{enumitem}

\xsimsetup{
  exercise/template = default,
  exercise/name = Aufgabe,
  solution/name = Lösung,
}

% from https://texwelt.de/fragen/23968/xsim-ubung-losung-zusatzlich-kurzlosung
\DeclareExerciseProperty{shortsolution}
\newcommand\printshortsolutions{%
  \begin{description}[leftmargin=3cm, style=sameline]
    \ForEachUsedExerciseByType{%
      \def\ExerciseType{##1}%
      \def\ExerciseID{##2}%
      \GetExercisePropertyT{shortsolution}%
        {%
          \item[Kurzlösung ##3] ####1%
        }%
    }%
  \end{description}
}
\NewEnviron{shortsolution}{\SetExpandedExerciseProperty{shortsolution}{\expandonce{\BODY}}}

\begin{document}
\begin{exercise}
  This is the exercise
\end{exercise}
\begin{shortsolution}
  This is the shortsolution
\end{shortsolution}
\begin{solution}
  The Solution
\end{solution}

% works only without this line
\printshortsolutions

\printallsolutions
\end{document}

我认为命令的语法肯定发生了变化，xsim但我无法在文档中发现它们。

Answer 1

从 0.19 版（2020/03/16）开始，和xsim仅在本地设置，以允许嵌套不同类型的练习。因此，不能再在练习之外使用。解决方案是移动\ExerciseType\ExerciseID\Set(Expanded)ExerciseProperty

\begin{shortsolution}
  This is the shortsolution
\end{shortsolution}

在练习中。

下面的代码演示了这一点，并且摆脱了environ——不再需要了。

\documentclass{scrartcl}

\usepackage{xsim}
\usepackage{enumitem}

\xsimsetup{
  exercise/template = default,
  exercise/name = Aufgabe,
  solution/name = Lösung,
}

\DeclareExerciseProperty{shortsolution}

\newcommand*\printshortsolutions{%
  \begin{description}[leftmargin=3cm, style=sameline]
    \ForEachUsedExerciseByType{%
      \def\ExerciseType{##1}%
      \def\ExerciseID{##2}%
      \GetExercisePropertyT{shortsolution}%
        {%
          \item[Kurzlösung ##3] ####1%
        }%
    }%
  \end{description}
}

\NewDocumentEnvironment{shortsolution}{b}
  {\SetExpandedExerciseProperty{shortsolution}{#1}}
  {}

\begin{document}

\begin{exercise}
  This is the exercise
  \begin{shortsolution}
    This is the shortsolution
  \end{shortsolution}
\end{exercise}
\begin{solution}
  The Solution
\end{solution}

\printshortsolutions

\printallsolutions

\end{document}