anchor.diff:  	  [{missing}] ->
   		missing;
   	  Result ->
  -		Result
  -%	  Result ->
  -%		lists:filter(fun({{missing, _},_,_}) ->
  -%			  false;
  -%			(_FilteredVersion) -> true  end, Result)
  +		lists:filter(fun({missing}) ->
  +			  false;
  +			(_FilteredVersion) -> true  end, Result)
   	end.
   
   %% Given a list of constraints filter said list such that only fail (for things
  
positive.code:         none ->
              [];
          {value, AllVsns} when is_list(AllVsns) ->
              [Vsn || {Vsn, _} <- AllVsns];
  		 _ ->
  		  []
      end.
  
  %% @doc
  %% make sure a given name/vsn meets all current constraints
  -spec valid_version(pkg_name(),vsn(),constraints()) -> boolean().
  valid_version(PkgName, Vsn, PkgConstraints) ->
    Constraints = get_constraints(PkgConstraints, PkgName),
  	  case lists:all(fun ({L, _ConstraintSrc}) ->
  			is_version_within_constraint(Vsn, L)
  		end,
  		Constraints) of
  	false ->
  	  lists:any(fun ({L, _}) ->
  			  is_version_missing(Vsn, L)
  		  end,
  		  Constraints);
  	true ->
  	  true
  	end.
  
  %% @doc
  %% Given a Package Name and a set of constraints get a list of package
  
negative.code:                 end,
                  ExistingConstraints0, [{SrcPkg, SrcVsn} | NewConstraints]).
  
  -spec is_version_within_constraint(vsn(),constraint()) -> boolean().
  is_version_within_constraint({missing}, _Pkg)->
      false;
  