`discourse-common` was created in the past to share logic between the
'wizard' app and the main 'discourse' app. Since then, the wizard has
been consolidated into the main app, so the separation of
`discourse-common` is no longer useful.
This commit moves `discourse-common/(lib|utils)/*` into
`discourse/lib/*`, adds shims for the imports, and updates existing
uses in core.
In development, Ember raises an error when previously-used values are updated during a render. This is to avoid 'backtracking', where parts of templates have to be re-rendered multiple times. In general, this kind of pattern should be avoided, and Ember's warning helps us do that.
However, for the deprecation warning banner, it is quite reasonable for some rendering to trigger a deprecation, and thereby require the global-notice to be re-rendered. We can use our `DeferredTrackedSet` to achieve that. Its `.add` method will delay adding an item to the Set until after the current render has completed.
Ported from d95706b25a
This is enabled by default, but can be disabled via the `warn_critical_js_deprecations` hidden site setting.
The `warn_critical_js_deprecations_message` site setting can be used by hosting providers to add a sentence to the warning message (e.g. a date when they will be deploying the Ember 5 upgrade).
