don't build a symbol that is already in the state (#70)

Author: mjheilmann

lib/grpc_reflection/service/builder.ex

@@ -91,7 +91,7 @@ defmodule GrpcReflection.Service.Builder do
         symbol: Enum.find(fields, fn f -> f.name == name end).type_name
       }
     end)
-    |> Enum.reject(fn %{symbol: s} -> s == nil end)
+    |> Enum.reject(fn %{symbol: s} -> is_nil(s) or State.has_symbol?(state, s) end)
     |> Enum.reduce(state, fn %{mod: mod, symbol: symbol}, state ->
       symbol = Util.trim_symbol(symbol)
 

test/service/builder_test.exs

@@ -141,12 +141,12 @@ defmodule GrpcReflection.Service.BuilderTest do
     assert %State{services: [WrappedService]} = tree
   end
 
-  @tag skip: "Recursive message structure currently fails to parse"
   test "handles a recursive message structure" do
     assert {:ok, tree} = Builder.build_reflection_tree([RecursiveMessage.Service.Service])
 
     assert tree.files |> Map.keys() |> Enum.sort() == [
              "recursive_message.Reply.proto",
+             "recursive_message.Request.proto",
              "recursive_message.Service.proto"
            ]