It is unclear how tree of tress whose root tree is not a document tree should behave.

[hayatoito]

After I replaced "node tree" with "component tree" in 588ecdf, I realized that it would affect the behavior of "tree of trees", in a sense before the commit, whose root tree is not a document tree.

The current spec does not say anything how such a disconnected (from a document) tree of trees should behave.

e.g.

const host = document.createElement('div');
const child = document.createElement('div');
const shadowRoot = host.attachShadow({mode: 'open'});
shadowRoot.appendChild(document.createElement('slot'));
// Note that host is not inserted into a document.
console.log(child.assignedSlot);  // What should be?

FYI. in current Blink's implementation, the distribution is correctly calculated even for such a disconnected tree of trees.

[hayatoito]

I think this is a minor issue. Let me label this with v2.

[annevk]

This is something we should have defined though, no? These are all v1 features.

[rniwa]

Indeed. This will impact interoperability of v1 API.

[hayatoito]

I got it. Let me use v1 label for all issues which may impact interoperability.

[hayatoito]

I'm going to fix the wording of the spec so that slot assigning API should work even in a such a disconnected tree of trees, whose root tree is not a document tree.