Raise DecodeError if the binary cannot be parsed (#81)

* Raise DecodeError if the binary cannot be parsed

* Change instrumentation

Author: haljin

lib/protobuf/decoder.ex

@@ -308,6 +308,10 @@ defmodule Protobuf.Decoder do
     raw_handle_varint(type, rest, result, val)
   end
 
+  defp raw_decode_varint(_, _, _) do
+    raise Protobuf.DecodeError, message: "cannot decode binary data"
+  end
+
   defp raw_handle_varint(:key, <<bin::bits>>, result, key) do
     tag = bsr(key, 3)
     wire_type = band(key, 7)
@@ -352,6 +356,10 @@ defmodule Protobuf.Decoder do
     raw_decode_key(rest, [<<n::64>> | result])
   end
 
+  def raw_decode_value(_, _, _) do
+    raise Protobuf.DecodeError, message: "cannot decode binary data"
+  end
+
   # packed
   defp put_packed_field(msg, %{wire_type: wire_type, type: type, name_atom: key}, val) do
     vals =

test/protobuf/decoder_test.exs

@@ -28,6 +28,12 @@ defmodule Protobuf.DecoderTest do
     end)
   end
 
+  test "raises for bad binaries" do
+    assert_raise(Protobuf.DecodeError, ~r{cannot decode binary data}, fn ->
+      Decoder.decode(<<0, 0, 0, 0, 0, 0, 0>>, TestMsg.Foo)
+    end)
+  end
+
   test "skips unknown varint fields" do
     struct = Decoder.decode(<<8, 42, 32, 100, 45, 0, 0, 247, 66>>, TestMsg.Foo)
     assert struct == TestMsg.Foo.new(a: 42, d: 123.5)