What is the expect behavior of wildcard reading CounterEntry with `counter_id = 0` and `index = x`?

[duskmoon314]

I'm reading the doc of reading and writing CounterEntry and getting confused about wildcard reading.

In the doc:

* If the `counter_id` field is set to 0 (default), the server returns the
  counter values for all indirect counter instances in the `ReadResponse`.

* If the `index` field is not set, the server returns the counter values for all
  indirect counters in the array identified by the unique id `counter_id`.

Is for all indirect counters actually for all indirect entries? It seems like a typo.

In the proto:

// - All counter cells for all counters if counter_id = 0 (default).
// - All counter cells for given counter_id if index is unset (default).

To my understanding, the results of different parameters are:

• counter_id: x, index: y => one entry of counter x and its index is y
• counter_id: x, index: UNSET => all entries of counter x
• counter_id: 0, index: UNSET => all entries of all counters
• counter_id: 0, index: y => Undefined behavior? Or all entries that index are y? Or does some error indicate that the parameter is illegal?

[antoninbas]

If the counter_id field is set to 0, then I would expect a P4Runtime implementation not to even bother looking at the index field, and the value you set should be irrelevant.

Maybe the second bullet point should just start with Otherwise,, to make it clear that these 2 checks are really ordered and mutually exclusive.

[chrispsommers]

@duskmoon314 Would you like to submit a PR to clarify the spec's language per @antoninbas 's feedback above? It'd be great to get your contribution. Thanks in advance!

[duskmoon314]

Sure! I have submitted a PR based on the feedback above.

I'm sorry for responding late due to some personal issue.