Demonstrate infinite loop and OOM error when passing duplicate attributes

[ceastlund]

No description provided.

[patricoferris]

Thanks @ceastlund, I can reproduce this and it looks like we're recursively building some string in some infinite loop. Will take a proper look for the fix:

[patricoferris]

@NathanReb -- seems we're swallowing the duplicated attribute error somewhere here:

diff --git a/src/context_free.ml b/src/context_free.ml
index 99e66890..56e3a904 100644
--- a/src/context_free.ml
+++ b/src/context_free.ml
@@ -366,7 +366,7 @@ let handle_attr_replace_once context attrs item base_ctxt : 'a option t =
           | [] -> return (false, Rule.Attr_replace.Parsed_payload_list.[])
           | x :: xs ->
               (if Attribute.Context.equal context (Attribute.context x) then
-                 Attribute.get_res x item |> of_result ~default:None
+                 return (Attribute.get x item)
                else return None)
               >>= fun p ->
               get_attr_payloads xs >>| fun (any_attrs, ps) ->