How do I enable protrusion for footnotes with \fnsymbol using microtype?

Question

In microtype package (v.2.5 beta 06) and footnote protrusion, custom protrusion for footnote numbers is enabled. However, as soon as I edit the footnote characters to the ones generated by \fnsymbol and alter the corresponding character to be protruded, it stops working. Here's an MWE for the footnote with numbers:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{geometry}
\geometry{a5paper,showframe}
\usepackage[protrusion=true,factor=2000]{microtype}
\SetProtrusion[context=footnote]{encoding=T1}{1={,650}}    

\makeatletter
\newcommand*\new@makefnmark{\hbox{\@textsuperscript{\normalfont
    \microtypecontext{protrusion=footnote}\@thefnmark}}}
\renewcommand*\@footnotemark{%
    \leavevmode \ifhmode\edef\@x@sf{\the\spacefactor}\nobreak\fi
    \new@makefnmark \ifhmode\spacefactor\@x@sf\fi \relax}
\makeatother

\begin{document}
Here's some text to show the behaviour of footnote marker at%
%
\footnote{A footnote}
%
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.
\end{document}

Here's an MWE for the footnote with the symbols defined by \fnsymbol:

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{geometry}
\geometry{a5paper,showframe}
\usepackage[protrusion=true,factor=2000]{microtype}
\SetProtrusion[context=footnote]{encoding=T1}{*={,650}}    
%\SetProtrusion[context=footnote]{encoding=T1}{\ast={,650}}    
%\SetProtrusion[context=footnote]{encoding=T1}{\textasteriskcentered={,650}}    
% None of the above work

\makeatletter
\newcommand*\new@makefnmark{\hbox{\@textsuperscript{\normalfont
    \microtypecontext{protrusion=footnote}\@thefnmark}}}
\renewcommand*\@footnotemark{%
    \leavevmode \ifhmode\edef\@x@sf{\the\spacefactor}\nobreak\fi
    \new@makefnmark \ifhmode\spacefactor\@x@sf\fi \relax}
\makeatother

\renewcommand{\thefootnote}{\fnsymbol{footnote}}
\begin{document}
Here's some text to show the behaviour of footnote marker at%
%
\footnote{A footnote}
%
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.
\end{document}

However, given the definition of \@fnsymbol I know for a fact that the symbol for the first footnote is *:

\fnsymbol=macro:
#1->\expandafter \@fnsymbol \csname c@#1\endcsname

\@fnsymbol=macro:
#1->\ensuremath {\ifcase #1\or *\or \dagger \or \ddagger \or \mathsection \or     mathparagraph \or \|\or **\or \dagger \dagger \or \ddagger \ddagger \else \@ctr
err \fi }

So my question is, how do I configure microtype correctly to get this to work? Note that I am using microtype v2.5. Below are the errors I get from running the nonworking MWE:

Package microtype Warning: I cannot find a protrusion list for font
(microtype)                `OT1/lmr/m/n/7' (context: `footnote'). Switching off
(microtype)                protrusion for this font on input line 20.


Package microtype Warning: I cannot find a protrusion list for font
(microtype)                `OT1/lmr/m/n/5' (context: `footnote'). Switching off
(microtype)                protrusion for this font on input line 20.


Package microtype Warning: I cannot find a protrusion list for font
(microtype)                `OT1/lmr/m/n/10' (context: `footnote'). Switching off
(microtype)                protrusion for this font on input line 20.

Answer 1

First, let us make it work with hyperref. hyperref redefines \@footnotemark itself, so instead of overwriting it, we just patch it with the etoolbox package.

\usepackage{etoolbox}
...
\makeatletter
\newcommand*\new@makefnmark{\hbox{\@textsuperscript{\normalfont
    \microtypecontext{protrusion=footnote}\@thefnmark}}}
\patchcmd{\@footnotemark}
  {\@makefnmark}
  {\new@makefnmark}{}{}
\makeatother

Next, let us protrude the footnote markers. We define the fonts that we want to protrude. I chose the default set alltext, plus the font of the footnote symbols:

\DeclareMicrotypeSet{alltextAndFootnotes}{%
  encoding = {OT1,T1,T2A,LY1,OT4,QX,T5,TS1,EU1,EU2}, %% alltext
  font     = {OMS/lmsy/m/n/scriptsize},
}

Next, we tell microtype that this is the set of fonts we want to protrude:

\microtypesetup{protrusion=alltextAndFootnotes}

Now we can define the actual protrusion:

\SetProtrusion[context=footnote]{encoding=OMS, family=lmsy,series=m, shape=n, size=scriptsize}{%
  "03={,650},%% *
  "78={,650},%% \mathsection
  "79={,650},%% \dagger
  "7A={,650},%% \ddagger
  "7B={,650},%% \mathparagraph
  "6B={,650},%% \|
  }

This would already be enough, but microtype complains that it has no protrusion settings for T1/lmr/m/n/7 and for OT1/lmr/m/n/7 etc., so let us provide some:

\SetProtrusion[context=footnote,load=lmr-T1,factor = 700]
  {encoding=T1, family=lmr, series=m, shape=n, size=scriptsize}
  {  }
\SetProtrusion[context=footnote,load=cmr-OT1,factor = 700]
  {encoding=OT1, family=lmr, series=m, shape=n}
  {  }

We just use the default protrusion settings for T1-encoded Latin Modern Roman, and OT1-encoded Computer Modern, scaled a little down. Change to your liking.

Complete MWE:

\documentclass[10pt]{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{etoolbox}

\usepackage{geometry}
\geometry{a5paper,showframe}

\usepackage[colorlinks]{hyperref}


\usepackage[protrusion=alltext,factor=2000]{microtype}

\DeclareMicrotypeSet{alltextAndFootnotes}{%
  encoding = {OT1,T1,T2A,LY1,OT4,QX,T5,TS1,EU1,EU2}, %% alltext
  font     = {OMS/lmsy/m/n/scriptsize},
}

\microtypesetup{protrusion=alltextAndFootnotes}
\SetProtrusion[context=footnote]{encoding=OMS, family=lmsy,series=m, shape=n, size=scriptsize}{%
  "03={,650},%% *
  "78={,650},%% \mathsection
  "79={,650},%% \dagger
  "7A={,650},%% \ddagger
  "7B={,650},%% \mathparagraph
  "6B={,650},%% \|
  }
\SetProtrusion[context=footnote,load=lmr-T1,factor = 700]
  {encoding=T1, family=lmr, series=m, shape=n, size=scriptsize}
  {  }
\SetProtrusion[context=footnote,load=cmr-OT1,factor = 700]
  {encoding=OT1, family=lmr, series=m, shape=n}
  {  }

\makeatletter
\newcommand*\new@makefnmark{\hbox{\@textsuperscript{\normalfont
    \microtypecontext{protrusion=footnote}\@thefnmark}}}
\patchcmd{\@footnotemark}
  {\@makefnmark}
  {\new@makefnmark}{}{}
\makeatother

\renewcommand{\thefootnote}{\fnsymbol{footnote}}

%% --------------------------------------------------------------
%% --------------------------------------------------------------
\begin{document}
Here's some text to show the behaviour of footnote marker at%
\footnote{A footnote}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{B}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{C}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{D}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{E}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{F}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{G}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{H}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.

Here's some text to show the behaviour of footnote marker at%
\footnote{I}
the end of a line, which disappears when the code for setting  microtypecontext is used in fnmark redefinition.
\end{document}

which gives