[EuiProvider] Configurable enforcement of provider usage

[thompsongl]

Summary

#6210

Consumers can set a module variable to 'log', 'warn', or 'error' with the setEuiDevProviderWarning method to capture instances where components are accessing the EUI theme (via useEuiTheme) but not using EuiProvider.

Checklist

• Checked for breaking changes and labeled appropriately
• A changelog entry exists and is marked appropriately
• Revert changes to src-docs/src/index.js

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_6216/

[thompsongl]

Pinging @chandlerprall for an early look

[thompsongl]

Another thought is to avoid the shape change and introduce Yet Another context provider

After more thought, not sure I like this idea so much

Although I'm not too concerned because no APIs would change (the global var would work the same way).

Comfortable moving forward with the current pattern and adjusting later as needed.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_6216/

[thompsongl]

The same check needs to be made for WithEuiTheme

withEuiTheme uses useEuiTheme so it works

What do you think of exporting computedTheme from this file and doing a strict equality check against the theme from the context? That would avoid the shape change and not need a new provider

Great call! I'll try this.

[chandlerprall]

withEuiTheme uses useEuiTheme so it works

Yep, sure does! Don't know how I missed that when I checked.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_6216/

[chandlerprall]

Changes LGTM; tested with the example toast in various configurations

[thompsongl]

@clintandrewhall Does this still look ok after the move from a global var to a module var?

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_6216/

[thompsongl]

CI failures will be resolved when I revert the test docs change

[clintandrewhall]

LGTM. We'll like follow this pattern with any Kibana context requirements.

Thanks for jumping on this so quickly! Shared UX will coordinate once this is released and in Kibana, just let us know.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_6216/