With beamer, "Missing { inserted." (regression)

[Sam Carter]

The code was improved to make the font commands overlay aware. Previously, only a couple of them, like `\textbf`, were overlay aware, now they are all consistent. The advantage is that the user can now control on which overlays a particular command should come into effect, e.g. 

\documentclass{beamer}

\begin{document}
\begin{frame}
$e_{\textnormal<2->{m}}$
\end{frame} 
\end{document}


> On 18. Feb 2022, at 04:12, Vincent Lefevre <vincent at vinc17.net> wrote:
> 
> On 2022-02-17 18:12:10 +0100, Sam Carter wrote:
>> The behaviour changed with the commit https://github.com/josephwright/beamer/commit/87f1646bd2307010701991129e5a900019b1d48c
> 
> Any reason why this has been broken?
> 
> Even though the behavior was not officially supported, there were
> no errors without the additional braces and this was simpler and
> more easily readable, so that it was probably used in practice.
> I can see that in many of my old .tex files (not all using beamer).
> 
>> You can make your old document work again with this workaround:
>> 
>> \documentclass{beamer}
>> 
>> \renewcommand{\textnormal}{\beameroriginal{\textnormal}}
> 
> Unfortunately, this makes pdflatex fail with TeX Live 2018.
> With .tex files shared among several users, this must work
> will all the TeX Live versions around.
> 
> I added additional braces. Fortunately, only 2 changes in the file
> were sufficient.
> 
> -- 
> Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)