Application Variables during Upgrade

A quick note related to my previous post: it turns out the application controller gives "old values" for application variables during the code upgrade process. Therefore the call to

element (2, application:get_key (drurly, modules))

returns the old list of modules, i.e., is missing new modules. ct_expand to the rescue! I get the list of modules at compile time from the application specification via

  Modules = 
    ct_expand:term (
      begin
        { ok, [ { application, drurly, PropList } ] } = 
          file:consult ("drurly.app"),
        case proplists:get_value (modules, PropList) of
          Y when is_list (Y) -> Y
        end
      end
    ),

For this to work, you must ensure the application specification is generated prior to compiling the module with this function in it.