This is true for proto3, but not for proto2 (except for repeated fields, which are always non-null but can contain 0 items). Proto2 has `HasFoo` methods, which

This is true for proto3, but not for proto2 (except for repeated fields, which are always non-null but can contain 0 items). Proto2 has `HasFoo` methods, which distinguish between empty (unset/null) and set explicitly to zero fields. I don't like that proto3 made this choice, I think it was wrong, but there was some rationale behind it beyond just "elegance".