GeneratedMessageCompanion#parseFrom always successful even for incompatible types

[mushtaq]

println(B.parseFrom(A("hello", 100).toByteArray)) // B(0, "")
println(A.parseFrom(B(100, "hello").toByteArray)) // A("", 0)

Is this intended? Then why do we have a "validate" method? Is there a sbt setting to change these defaults and make it throw exception?

[thesamet]

It depends on the definitions of A and B, but generally there is no way for the parser to know that it is getting bytes that are meant for a different message types. In some cases, it can detect that a message does not make sense and then it would throw an exception. The validate function is returning a Try that fails when those cases happen.

This behavior is a feature of the protobuf wire format that allows you to evolve your message schema.
https://developers.google.com/protocol-buffers/docs/proto#updating