it was wrong to change the default; back to old conservative default

Author: kuenishi

include/msgpack.hrl

@@ -81,7 +81,7 @@
 
 -else.
 -record(options_v3, {
-          interface = map :: format_type(),
+          interface = jiffy :: format_type(),
           map_unpack_fun = fun msgpack_unpacker:unpack_map/3 ::
                                  msgpack_map_unpacker(),
           impl = erlang      :: erlang | nif,

test/msgpack_test.erl

@@ -145,12 +145,25 @@ issue_jiffy_5_test() ->
 
 
 issue_27_test_() ->
-    [?_assertEqual({ok, null},
+    [
+     %% nil(jiffy) => nil(msgpack) => null(jsx)
+     ?_assertEqual({ok, null},
                    msgpack:unpack(msgpack:pack(nil), [{format,jsx}])),
+
+     %% nil(jiffy) => nil(msgpack) => nil(jiffy)
      ?_assertEqual({ok, nil},
                    msgpack:unpack(msgpack:pack(nil, [{format,jiffy}]))),
+
+
+     %% null(jsx) => nil(msgpack) => nil(jiffy)
+     ?_assertEqual({ok, nil},
+                   msgpack:unpack(msgpack:pack(null, [{format,jsx}]))),
+
+     %% null(jiffy-atom) => <<null>>(msgpack-binary) => <<"nil">>
      ?_assertEqual({ok, <<"null">>},
                    msgpack:unpack(msgpack:pack(null, [{allow_atom,pack}]))),
+
+     %% nil(jsx-atom) => <<nil>>(msgpack-binary) => <<"nil">>
      ?_assertEqual({ok, <<"nil">>},
                    msgpack:unpack(msgpack:pack(nil,
                                                [{format,jsx},{allow_atom,pack}])))].