footmisc + marginfix + (\marginpar or todonotes) = error

Feeding

\documentclass{article}
\usepackage{footmisc}
\usepackage{marginfix}
\begin{document}
\marginpar{test}
\end{document}

or

\documentclass{article}
\usepackage{footmisc}
\usepackage{marginfix}
\usepackage{todonotes}
\begin{document}
\todo{test}
\end{document}

to pdflatex leads to a compilation error:

! Package marginfix Error: lost some margin notes.

See the marginfix package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.7 \end{document}
                  
?

Unfortunately, the explanation of “lost some margin notes” in § 13 of the documentation of marginfix says nothing to me. Having a bit more text, say,

\begin{document}
test

\marginpar{test}% or \todo{test} if you happen to use todonotes

test
\end{document}

doesn't help.

Used versions:

• pdfTeX, Version 3.141592653-2.6-1.40.24 (TeX Live 2022/Debian)

• LaTeX2e <2022-11-01>

• L3 programming layer <2022-11-02>

• article 2022/07/02 v1.4n

• footmisc 2022/03/08 v6.0d

• marginfix 2020/05/06 v1.2

• todonotes 2021/06/04 v1.1.5

These versions were in TeX Live in Debian-testing this spring.

Who is the culprit? Any more permanent bugfix than \usepackage{footmisc}[=v5] (thx to David Carlisle) or loading marginfix before footmisc (thx to Frank Mittelbach)?

Crossposts: http://github.com/FrankMittelbach/fmitex-footmisc/issues/10 and http://github.com/henrikmidtiby/todonotes/issues/71 .

Old version of the same bug: http://tex.stackexchange.com/questions/652835/footmisc-marginfix-todonotes-error .

Probably related: http://github.com/shicks/marginfix/issues/18 .

[shicks]

Thanks @FrankMittelbach for the explanation in FrankMittelbach/fmitex-footmisc#10.

It sounds like marginfix will be permanently (but fixably) broken at some point in the future, but that the correct behavior will depend on what version of LaTeX is being used.

I'm happy to update it, but I've been out of the scene for a while - is it better to detect the version/conflict and try to handle both, or just to set the minimum kernel version and expect the distribution to pair the right versions together? Is there an ETA for when any hooks will be available?

In the meantime, would it make sense to detect that footmisc is already loaded and give a more actionable error message? Or maybe it won't matter since by the time a new version shows up in TeXLive, then footmisc will already have been updated?

[FrankMittelbach]

As of today or maybe tomorrow there is no need to update because I altered footmisc so that it remains offering \@combinefloats for patching. Whether that remains possible once the kernel actually changes remains to be seen (but we try to offer alternatives (and solutions) if packages patch low-level and needs an update in such situations). For now no action is necessary.

[DanielWicz]

@FrankMittelbach How did you alter footmisc ?

[FrankMittelbach]

@FrankMittelbach How did you alter footmisc ?

FrankMittelbach/fmitex-footmisc@cafac13