For some reason, nil? is sent to the XmlMarkup object. If nil? is not defined and method_missing is invoked, some strange kind of recursion happens. Since nil? won’t ever be an XML tag, it is pretty safe to define it here. (Note: this is an example of cargo cult programming, cf. fishbowl.pastiche.org/2004/10/13/cargo_cult_progra...).

Source Code

# File builder/xmlbase.rb, line 107
def nil?
  false
end