Beamer patching footnotes warning: "Patching footnotes failed. Footnote detection will not work."

Question

Consider the following MWE

\documentclass{beamer}

\usepackage{lmodern}
\usepackage[style=authoryear-comp,backend=biber]{biblatex}

\begin{document}
\begin{frame}
  Foo
\end{frame}
\end{document}

This will give the warning:

Package biblatex Warning: Patching footnotes failed.
(biblatex) Footnote detection will not work.

I read here and in this answer that the warning can be safely ignored. Can I force biblatex to avoid giving the warning altogether?

Answer 1

This warning is issued during package loading as biblatex attempts to patch certain commands (using etoolbox). So, there's no way of avoiding this message directly without editing a .sty file (biblatex2.sty in this case) or using alternate means... like the silence package.

\documentclass{beamer}
\usepackage{silence,lmodern}
\usepackage[style=authoryear-comp,backend=biber]{biblatex}
% Filter warnings issued by package biblatex starting with "Patching footnotes failed"
\WarningFilter{biblatex}{Patching footnotes failed}

\begin{document}
\begin{frame}
  Foo
\end{frame}
\end{document}

Answer 2

Versions of biblatex starting from 3.10 support patching beamer's footnote commands so that footnote detection works and no warning is issued.

If you still get this warning you should look into updating biblatex (and with it Biber).

See also Beamer and biblatex possible remedy for warning: Patching footnotes failed, https://github.com/plk/biblatex/issues/581 and https://github.com/plk/biblatex/commit/5169d2a64777090aa29d38df7543301f5c8b876b