Hi; default values *are not sent*, especially in proto3 where zero is
default and default is zero. Likewise, the root object in a message is not
wrapped in any way - only fields *on* the root object.

This means that the binary encoding of a CommandRequest with Code.RESET is:
zero bytes, which is a perfectly valid size in protobuf.

Sometimes, people find it convenient / helpful to use a DEFAULT / NONE /
UNKNOWN = 0, with their *actual* enum values above that. This makes the
default experience easier to understand, and avoid problems.

Marc

On Thu, 16 Jan 2020 at 08:08, Burak Kirazli <[email protected]> wrote:

> Hello,
>
> I am new to protobuf.
>
> I have a request message like that
>
> message CommandRequest
> {
>     enum Code
>     {
>         RESET = 0;
>         ERASE_APP = 2;
>         ERASE_OTA = 3;
>     }
>
>     Code code = 1;
> }
>
> When I am trying to encode a request with zero value, i see that encoded
> size is zero. What will be exchanged?
>
>     //Qt project
>
>     CommandRequest req;
>     req.set_code(CommandRequest_Code::CommandRequest_Code_RESET);
>     qDebug() << req.ByteSizeLong() << endl;
>
>     //Output of this code is:
>     0
>
>
> Thanks.
>
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-- 
Regards,

Marc

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