you are still relying on mwc elementes to be defined globally by HA

The changes you made to start using the scoped custom element registry (according to https://developers.home-assistant.io/blog/2022/02/18/paper-elements/ and https://developers.home-assistant.io/blog/2020/10/02/lazymoreinfo/#what-about-external-elements) are not bulletproof just yet. The idea is that your card relies entirely on its own bundled elements in order to work and here it is violated.

Let’s take for example the mwc-list-item custom element you added. This element, internally, renders mwc-ripple. Since you didn’t define your custom class as a ScopedRegistryHost, the internal mwc-ripple element, will only be rendered if the global registry defines it (which is currently being done by HA). If HA suddenly drops the support for MWC, the element will not be rendered properly. This happens because ScopedRegistryHost is not recursive, and only applies to the elements directly rendered by it.

The solution I applied in other cards (https://github.com/artem-sedykh/mini-climate-card/pull/67 for example), is to define each custom element as ScopedRegistryHost as well while setting its used elements as well (https://github.com/regevbr/mini-climate-card/blob/f61364816c5667370eebc5a44168713e5c36ea02/src/components/mwc/list-item.js#L7-L17) If you are willing, I don’t mind drafting a PR.

Another issue, that also relates to how HA sees custom cards - Custom Cards using the elements used in the Home Assistant Frontend have never been supported (taken verbatim from the above-mentioned blog posts). So it seems that using `ha-card- here should also be removed.

@iantrich I would appreciate your input on the matter (I hope I was clear enough)

[regevbr]

The idea is that the custom card only has 1 custom registry, not every element. By passing the registry of the host down we make sure they all share the same registry.

There really isn’t much magic going on, and by creating a mixin like I did here #52 (comment) I don’t think it is verbose at all?

I see your point, but you are creating a “global” registry just for the card. There can still be conflicts between elements when you do that, if, for example, you use a couple of libraries. I prefer the encapsulations of my method, but they both work, so it is just a question of style.

[bramkragten]

The idea is that the custom card only has 1 custom registry, not every element. By passing the registry of the host down we make sure they all share the same registry.

There really isn’t much magic going on, and by creating a mixin like I did here https://github.com/custom-cards/boilerplate-card/issues/52#issuecomment-1064009326 I don’t think it is verbose at all?