Error when deserializing map with default (missing) value

[peterhuene]

I'm using a protocol definition that has a message containing a map<string,string>.

When the map contains an empty value (e.g. "Foo" => ""), the C# protobuf implementation serializes field 1 (i.e. the "key") with a value of "Foo" and does not serialize a field 2 (i.e. the "value").

According to the protobuf documentation on default values, it appears this is completely legal and deserializers should treat the missing field as "default" (in this case, an empty string).

However, read_map_into explicitly checks for (_, None) and errors:

rust-protobuf/protobuf/src/rt.rs

Line 980 in c8e7631

(None, _) | (_, None) => return Err(ProtobufError::WireError(WireError::IncompleteMap)),

The result is an IncompleteMap error instead of the expected map containing an empty string value.

[stepancheg]

Yes, you are right. Thank you!

MapField.cs
FieldCodec.cs

Going to fix it.

[stepancheg]

Published versions 2.0.3 and 1.7.4 with fix.

[peterhuene]

Thanks for the quick fix!