Package option (for xcolor) is not being properly used in beamer

Question

After a recent upgrade of my system (to Ubuntu 22.04), many of my previous files are failing to compile with undefined colors.

Please see the following self-contained examples for clarification.

---

The following works fine.

% 1
% Base colors (always available)
\documentclass{article}

\usepackage{xcolor}

\begin{document}

\LaTeX

{\color{blue}\LaTeX}

\end{document}

Conclusion: The xcolor package is working fine for the base colors.

---

The following works fine as well.

% 2
% Colors via dvipsnames option
\documentclass{article}

\usepackage[dvipsnames]{xcolor}

\begin{document}

\LaTeX

{\color{Blue}\LaTeX}

\end{document}

Conclusion: The xcolor package is working fine for the colors via option.

---

The following is also good.

% 3
% Base colors (always available)

\documentclass{beamer}

\begin{document}

\begin{frame}
  \LaTeX
  
  {\color{blue}\LaTeX}

\end{frame}

\end{document}

Conclusion: beamer properly handles the base colors in the xcolor package.

---

This is where the problem starts.

% 4
% Colors via dvipsnames option
\documentclass[xcolor=dvipsnames]{beamer}

\begin{document}

\begin{frame}
  \LaTeX
  
  {\color{Blue}\LaTeX}

\end{frame}

\end{document}

We get the following error message.

! Package xcolor Error: Undefined color `Blue'.

Conclusion: beamer fails to handle the colors via option in xcolor package.

---

The following is likely to generate an option clash, naturally.

% 5
% Colors via dvipsnames option
\documentclass{beamer}

\usepackage[dvipsnames]{xcolor}

\begin{document}

\begin{frame}
  \LaTeX
  
  {\color{Blue}\LaTeX}

\end{frame}

\end{document}

We get the following error message.

! LaTeX Error: Option clash for package xcolor.

---

Even the following does not work when we pass the option explicitly.

% 6
% Colors via dvipsnames option
\documentclass{beamer}

\PassOptionsToPackage{dvipsnames}{xcolor}

\begin{document}

\begin{frame}
  \LaTeX
  
  {\color{Blue}\LaTeX}

\end{frame}

\end{document}

We get the following error message.

! Package xcolor Error: Undefined color `Blue'.

---

Final Conclusion: Something is wrong with beamer making it to fail to handle the xcolor package options.

Answer 1

This is due to a bug in beamer v3.65 which was fixed in beamer v3.66. Those who are forced to use this version (upgrades may be difficult when you install the complete system), you can use the following workaround.

Load xcolor or use the macro \PassOptionsToPackage{...} before \documentclass{...}.

Use either of the following before \documentclass{...} in your file,

\RequirePackage[dvipsnames]{xcolor}

\PassOptionsToPackage{dvipsnames}{xcolor}

The second one is more modular.