What should gNMI Get do when there's no data to be returned?

[kyoungyun]

Hi.
What should be the gNMI Get behavior when there’s no data to be returned from a query on a valid path? The spec. seems to be unclear about this. Which one of the following should be returned?

• an empty json_val/json_ietf_val (i.e., "")
• “{}” in json_val/json_ietf_val
• no val field at all
• an error
• something else

[aashaikh]

Agree this could use some clarification. I expect there are some different perspectives depending on the situation -- e.g., a query for a list element that doesn't exist (similar to #119), a configuration value that has not been set, an opstate value that has a valid path but is not supported by the platform, etc.