This flag defaults to false for new Documents, such as the one created
here for use by template elements' contents. Without setting it to
true, nothing inside a template can have a declarative shadow dom.
As noted, this appears to be a spec issue. I am not convinced that this
is the correct fix, but it is simple and does solve the issue without
any apparent regressions.
This would happen for example when removing a slot element from the DOM,
in which case it would keep its old list of assigned slottables even
though it now has none. Fixes a couple of WPT tests.
We use a Vector for this, but its spec definition is an ordered set.
That means we need to ensure we don't add duplicates. This fixes issues
where we would send slotchange events multiple times to the same
HTMLSlotElement.
In the current spec, MutationObservers are explicitly added to the
pending mutation observers list, and they are removed when that list is
cleared in the "notify mutation observers" microtask.
This solves some issues with slotchange events.
As noted, we delay actually emptying the list of pending mutation
observers until after we're finished with the "clone", because we can't
actually copy or move the intrusive list. As far as I am aware, this
should not affect behaviour because only one microtask can run at once.
If attachment fails for whatever reason (e.g the host element is not
allowed to be a host), the HTML spec tells us to insert the template
element anyway and proceed.
Before this change, we were recomputing the insertion location at this
point, which caused it to be *inside* the template element. Inserting
the template element into itself didn't work, and so the DOM would end
up incorrect.
The fix here is to simply use the insertion point we determined earlier
in the same function, before putting a template element on the stack of
open elements. We already do this elsewhere.
Fixes at least 228 subtests on WPT. :^)
There are ARIA attributes, e.g. ariaControlsElements, which refer to a
list of elements by their ID. For example:
<div aria-controls="item1 item2">
The div.ariaControlsElements attribute would be a list of elements whose
ID matches the values in the aria-controls attribute.
The property-reflection.html test was partially split into a second file
recently, property-reflection-imperative-setup.html. Let's re-import to
ensure we have the latest. See:
https://github.com/web-platform-tests/wpt/commit/2518df1
Let's simply reinsert the element respecting it's new position in the
DOM tree, instead of crashing.
Fixes regression in WPT tests caused by introducion of cache for
getElementById().
