Optional added back to proto3

[tsloughter]

optional was added back to proto3 protocolbuffers/protobuf#8959

I think this means if a field is marked optional now that even in proto3 it should be undefined instead of the default?

[tomas-abrahamsson]

Yes, that seems right. I think this is what gpb does as well, or did you find some situation where it is wrong?

syntax='proto3';
message m {optional uint32 f = 1;}

1> issue214:decode_msg(<<>>, m).
{m,undefined}

Edit: support for optional in proto3 was added to gpb in 4.13.0

[tsloughter]

Oh, hah, thanks, I should have tried first but instead based it on my earlier usage (I guess before 4.13) and misreading the README -- your README is actually pretty clear now that I reread it, I guess my eyes just glazed over after reading docs all over about whether proto3 really added optional back or not :)

[tomas-abrahamsson]

No probs :)