I want to understand if the messages bellow are compatible from the perspective of protobuf and serialization/deserialization.
message HelloReply {
string message = 1;
string personalized_message = 2;
}
message HelloReply {
string personalized_message = 2;
string message = 1;
}
Does the order matter for compatibility in any situation?
>Solution :
The textual order is largely irrelevant, although it may impact some code generation tooling – but most languages don’t care about declaration order, so even that: won’t matter. The fields are still defined semantically equivalent – the numbers match the existing meaning (name) and type. It is the number that is the determining feature in identifying a field.
At the protocol level:
- parsers must allow fields in any order
- serializers should (but not must) write fields in ascending numerical field order