Re: [mediacapture-main] Bug in spec: circular dependency for enumerateDevices() (#709)

> > @hills to make sure I understand clearly your request: if permission to a device is granted, but opening that device fails for other reasons, then you argue that `enumerateDevices()̀` permission should be granted?
> 
> Yes.

Let's concentrate solely on this point in this issue.
And let's look at the pros and cons you mentioned above.

> The upsides of the change:
> a perceived "privacy enhancement" around capture indicators. But our discussion shows this change cannot be realised in practice.

Let's say a device is always broken and page somehow knows it.
A page could try to call getUserMedia with exact constraints on that device.
Without the change, the getUserMedia call would fail and the page would be granted enumerateDevice permission.
User has no way to notice this information leakage.

With the change, the web page will not have access to that info and will have to open a functional device, which will trigger the capture indicator. This makes it highly unlikely that pages that want that information for learning about user (but not call getUserMedia) will actually take the risk to be discovered.

The benefits are realised in practice.
If we widen the scope of the issue, we increase the privacy benefits.

> The downsides:
> change in API behaviour affects existing code in the wild
> the new behaviour is unusual and not straightforward (I am not the only person already asking for clarification)
> the new behaviour is not efficient (examples given require multiple device opens to workaround new behaviour)

I do not see how these downsides are related to the case you mention above (capture fails due to a hardware issue).
Note that the spec is further reducing the edge case to the case of all selectable devices are failing, not just the one.
Can you clarify what benefits you see in granting enumerateDevices permission in case all selectable devices fail to open?

-- 
GitHub Notification of comment by youennf
Please view or discuss this issue at https://github.com/w3c/mediacapture-main/issues/709#issuecomment-688472076 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Monday, 7 September 2020 18:46:54 UTC