bug#57969: 29.0.50; `device-class' errors when NAME is nil

[Visuwesh]

[புதன் செப்டம்பர் 21, 2022] Lars Ingebrigtsen wrote:

> But it's not clear what the meaning of nil should be.  Perhaps Po Lu
> knows; added to the CCs.

last-event-device has this to say,

    It is nil if the last event did not come from an input device (i.e. it
    came from ‘unread-command-events’ instead).

>
> (And if nil really is a meaningful value for NAME, and not just a
> documentation error, then perhaps that argument should be optional?)