Gutenberg: Slot/Fill - `updateSlot` is missing from Slot Fill Context.

[StevenDufresne]

Describe the bug
I'm trying to use @wordpress/block-editor as a standalone library and copied the example.

I am unable to get it running because, it appears like this call:

https://github.com/WordPress/gutenberg/blob/8ac282605512cb4ee0c90973b60e1d01596df018/packages/components/src/slot-fill/bubbles-virtually/slot.js#L34

is failing because updateSlot is undefined as it's not part of the slot-fill-context.

https://github.com/WordPress/gutenberg/blob/8ac282605512cb4ee0c90973b60e1d01596df018/packages/components/src/slot-fill/bubbles-virtually/slot-fill-context.js#L6

Instead, it appears to have moved to the useSlot hook:
https://github.com/WordPress/gutenberg/blob/8ac282605512cb4ee0c90973b60e1d01596df018/packages/components/src/slot-fill/bubbles-virtually/use-slot.js#L18

In this PR:
https://github.com/WordPress/gutenberg/pull/19242

To reproduce
Steps to reproduce the behavior:
I used Create React App to get started.

1. Create React app.
2. Install everything listed in the @wordpress/block-editor example https://www.npmjs.com/package/@wordpress/block-editor#usage
3. Try to run app.
4. Expect to see this:
   

Editor version (please complete the following information):
Pulled from package.json:

 {
    "@wordpress/block-editor": "^4.0.0",
    "@wordpress/block-library": "^2.19.0",
    "@wordpress/components": "^9.7.0",
    "@wordpress/element": "^2.14.0",
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-scripts": "3.4.1"
}

Desktop (please complete the following information):

• OS: macOs (Catalina)
• Browser: Chrome

[gziolo]

@youknowriad or @diegohaz, could you advise what would be the preferred fix here?

[diegohaz]

Due to the convention that this module adopts, I think the preferred fix is to simply add updateSlot as a noop function to the default object that is returned by the context (when SlotFillProvider isn't present). I'll fix this asap. But I also wonder when using Slot/Fill without SlotFillProvider would make sense.

[gziolo]

But I also wonder when using Slot/Fill without SlotFillProvider would make sense.

I think it’s must have to wrap both of them with SlotFillProvider. We could add some warnings to both of them to ensure it’s always properly configured.