Negative number into uint32 encodes/decodes incorrectly

[eaguilera23]

Set up for replication

defmodule Unsigned do
  use Protobuf, """
    message Negative {
      required uint32 issue = 1;
    }
end
  """

Replicate issue

iex> Unsigned.Negative.new(issue: -420) |> Unsigned.Negative.encode |> Unsigned.Negative.decode
%Unsigned.Negative{issue: 92}

iex> Unsigned.Negative.new(issue: -2) |> Unsigned.Negative.encode |> Unsigned.Negative.decode
** (FunctionClauseError) no function clause matching in :gpb.de_vi/4

    The following arguments were given to :gpb.de_vi/4:

        # 1
        ""

        # 2
        7

        # 3
        126

        # 4
        32

    (gpb) src/gpb.erl:856: :gpb.de_vi/4
    (gpb) src/gpb.erl:357: :gpb.decode_type/3
    (gpb) src/gpb.erl:244: :gpb.decode_field/4
    (exprotobuf) lib/exprotobuf/decoder.ex:22: Protobuf.Decoder.decode/2

Related issues (maybe)

mafintosh/protocol-buffers#62

[sneako]

An unsigned integer is only supposed to hold positive values. You should be using int32 instead if you need to encode negative values.

[eaguilera23]

Oh ok. I thought it would turn a -40 into 40 at encoding time. My bad then.