\version "2.13.40"

% Storing a \bookpart in a variable is possible. It works fine if the bookpart
% does not contain any top-level markup. As soon as the bookpart, that is stored
% in a variable, contains a markup, lilypond will always segfault:

\header {
  title = "Title of my score"
}

mypart = \bookpart {
  % This works:
  \relative c' { c1 }
  % If the bookpart contains a markup, then lily crashes. If you comment
  % the markup, everything works fine:
  \markup { asdf }
}


% The bookpart written at top-level (not stored in a variable) works also with
% markups:

\bookpart {
  \relative c' { c1 }
  \markup { asdf }
}

% This crashes lilypond:
\bookpart { \mypart }