Re: What does "navigationStart" mean as a second argument to performance.measure() in a web worker?

On 12/15/16 2:57 PM, Philippe Le Hégaret wrote:
> You cannot have a PerformanceMark using the "navigationStart" in
> non-Worker case.

Yes, I'm aware.

> The spec says to throw a SyntaxError if you try to
> create one. It doesn't say that for Workers however and I don't think we
> should enable it.

Sure.  Note that at least some implementations do disallow 
performance.mark("navigationStart") in workers, but they may predate 
this spec...

> I guess we should link to how PerformanceMarks get created instead of
> the interface definition but that wouldn't be enough to address your issue.

True.

> I need to make sure the spec takes this into account and allows cover
> the tests in:
> https://w3c-test.org/user-timing/test_user_timing_measure_exceptions.html

The fact that the abovementioned implementations pass all user-timing 
web platform tests is a bit unfortunate.  ;)

> So, you asked what "navigationStart" means as a second argument to
> performance.measure() in a web worker. In this case, unless you did
> explicitly create a PerformanceMark object with that name, it would
> throw a SyntaxError... which isn't writing down in the spec.

Lovely.  ;)

> In summary, I need to raise a bunch of issues against the spec but feel
> free to beat me to it.

I'm not likely to have much time to spend on this.  Not least because, 
honestly, it feels like a bad investment of my time to spend much of it 
reading these specs in the state they're in.  :(

> I agree we have an interdependencies issue but this is not just limited
> to the perf specs imho. We link to a bunch of other specs as well and
> don't track those dependencies well.

I think the coupling with the other specs is somewhat looser, so you 
don't have the same problems with having to read all of them in parallel 
to make any sense of any of them.

-Boris

Received on Thursday, 15 December 2016 21:05:38 UTC