default value unexpected behaviour

[gismoranas]

I have this protobuf code

message Foo { optional int32 schema = 1 [default = 11]; }

If I run this

val foo = new Foo(None)
println(foo.parseFrom(foo.toByteArray).getSchema) // 11
println(foo.parseFrom(foo.toByteArray).schema) // None

I suppose you set 11 in the getter instead of setting Some(11) in schema directly. Isn't this an inconsistent state?

[thesamet]

This distinction between set and unset fields comes from the proto2 spec. A field may be either present or not in a message, which is modeled in ScalaPB as (Some(_) or None). Only when you call getX the default value is provided.

This is modeled after the official Java implementation, see "Singular value fields" at https://developers.google.com/protocol-buffers/docs/reference/java-generated#fields
which they have for each field X two methods: hasX() and getX(). We basically combine these two to a single optional field.

[thesamet]

Exactly. We're just mapping these two fields to a single Option. You may be interested in trying proto3, where primitives are not wrapped in Options, but there are no default values either (default is 0 for numerics, empty string, etc)