Behavior when event data cannot be provided is underspecified

[rakuco]

Each of the 3 event types defined in this specification have an excerpt that looks like this:

If an implementation can never provide motion information, the event should be fired with the acceleration, accelerationIncludingGravity and rotationRate attributes set to null.

This does not look entirely clear to me:

• Should implementations fire a single event with nullable attributes set to null, or does the text intend to give implementations some leeway so that they can continue trying (and consequently fire any number of "empty" events)?
• Doesn't it make more sense to just not fire an event at all?

[reillyeon]

I think Chromium puts the sensor into an essentially "stopped" state and so only one event is fired but the concept of "stopped" and "started" don't really exist in this spec.

[anssiko]

Do we want to try address this by the upcoming CR Snapshot or defer for later? Works both ways.

Discussed in https://www.w3.org/2024/02/12-dap-minutes.html#t10

[reillyeon]

@rakuco took an action item to discover what the implementation consensus (if any) is on this behavior. If the answer is simple we could adjust the specification test to clarify but I don't think this is blocking.