anchor.diff:  consult_app_file(Filename) ->
       case filelib:is_file(Filename) of
           false ->
  -            throw(?PRV_ERROR(invalid_app_file));
  +            {error, enoent};
           true ->
               case lists:suffix(".app.src", Filename) of
                   false ->
  
positive.code:     %% Load the app file and validate it.
      validate_app(State, App1).
  
  format_error(invalid_app_file) ->
      "Failed to read app file";
  format_error({file_read, File, Reason}) ->
      io_lib:format("Failed to read ~s for processing: ~p", [File, Reason]);
  format_error({invalid_name, File, AppName}) ->
      io_lib:format("Invalid ~s: name of application (~p) must match filename.", [File, AppName]).
  
  
negative.code:             Resources = rebar_state:resources(State),
              rebar_utils:vcs_vsn(get_value(vsn, AppData, AppFile), AppDir, Resources);
          {error, Reason} ->
              throw(?PRV_ERROR({file_read, AppFile, Reason}))
      end.
  
  get_value(Key, AppInfo, AppFile) ->
  