[adamson]

> Things that you might expect to be invalid, are valid. A zero byte array deserialised as a protobuf message is a perfectly valid message. All the strings are "" (not null), the bools false, and the ints 0.

How does this work? How do you make, say, all fields but the second null? Do you just send a messages that's (after encoding) as long as the first two fields, where the first field is 0x00 and the second contains whatever data you want?

[violinist]

Two things: 1) proto buffers intentionally don't allow null values; values that aren't set will return a default value 2) gRPC uses proto3, which does not distinguish between a field unset and a field set to the default value