Fix issues with protobuf equality comparisons

lib/src/protobuf/utils.dart

Index: lib/src/protobuf/utils.dart
diff --git a/lib/src/protobuf/utils.dart b/lib/src/protobuf/utils.dart
index 364d78f21ff96cb5261ffb871bacbed8b4823a64..31fafcc2d5d73fbe8191920dcacca7a4958b0aff 100644
--- a/lib/src/protobuf/utils.dart
+++ b/lib/src/protobuf/utils.dart
@@ -6,6 +6,10 @@ part of protobuf;
 
 // TODO(antonm): reconsider later if PbList should take care of equality.
 bool _deepEquals(lhs, rhs) {
+  // Some GeneratedMessages implement Map, so test this first.
+  if ((lhs is GeneratedMessage) && (rhs is GeneratedMessage)) {

[Søren Gjesse, 2016/04/04 16:06:27]

Maybe negate this if to only have one lhs == rhs.

if (!(lhs is Gener... {
  if ((lhs is List) ...
  if ((lhs is List) ...
  ...
}
return lhs == rhs;

[skybrian, 2016/04/04 19:38:02]

As a style thing, I'd rather repeat the == check than have nested if statements.

I changed this code slightly to ensure that if only one or the other is a
GeneratedMessage, it will return false. But I don't think this will come up in
practice except in contrived situations.

+    return lhs == rhs;
+  }
   if ((lhs is List) && (rhs is List)) return _areListsEqual(lhs, rhs);
   if ((lhs is Map) && (rhs is Map)) return _areMapsEqual(lhs, rhs);
   if ((lhs is ByteData) && (rhs is ByteData)) {