Popover: spec for dealing with element removal is incorrect

[jakearchibald]

https://html.spec.whatwg.org/multipage/infrastructure.html#dom-trees:hide-popover-algorithm

When a popover is removed from the DOM, it calls the hide popover algorithm.

That algorithm will always exit on step 1, since the removed element is no longer connected to the document.

[jakearchibald]

I think the behaviour here needs some design. Does it make sense to fire all of the events in this case?

[mfreed7]

I agree that the spec is broken for this case. The difference between the spec and at least the Chromium implementation is that the spec for remove runs the removing steps at step 15, but removes the node from the tree before that, at step 11. The Chromium impl runs that call to HidePopoverInternal before the node is removed from the tree.

I'm not sure what the best way to fix the spec is. Seems like there might need to be "before removing steps" added before step 11 or something? @josepharhar @annevk @nt1m

[mfreed7]

Does it make sense to fire all of the events in this case?

We discussed this at great length during the spec PR review. The problem is that events can't be fired synchronously during removal, so we'd have to queue the events in this case, which leads to myriad problems like out of order events. So we decided that the best course of action was not firing events in this case.

[nt1m]

Yes, WebKit also runs removing steps before removing the node from the tree. That part of the spec is definitely broken here.

[josepharhar]

I opened a DOM PR to add "before removing steps" that can hook into here: whatwg/dom#1185

[josepharhar]

I opened an HTML PR which should make the above DOM PR obsolete by fixing this bug in a different way #9457