[components] Isolated Imports and Foreign Custom Elements

Hi everyone,

I wrote up a proposal (with input and advice from Ryosuke Niwa) on a possible way to extend Web Components to support fully isolated components:

https://github.com/w3c/webcomponents/wiki/Isolated-Imports-Proposal <https://github.com/w3c/webcomponents/wiki/Isolated-Imports-Proposal>

I welcome comments on whether this approach makes sense.


I’d also like to discuss this during the proposals section of tomorrow’s F2F. I know it’s supposed to be focused on Shadow DOM, but I think this proposal is relevant context.

I think this proposal, even if it is itself a post-v1 project, helps explain why closed mode is important and relevant. While closed mode doesn’t provide strong security isolation by default, its a building block that can be used to build full isolation, whereas open mode can’t be used that way.

If we agree to have a closed mode eventually, then it’s probably sensible to add it for v1. We’d also want to decide sooner rather than later whether closed or open is the default (or whether there is no default and we require authors to choose one explicitly).

Regards,
Maciej