Unclear whether we can use imports from index.js files of core (DLL) packages?

[Reinmar]

See:
Originally posted by @Reinmar in #10352 (comment)

The below change does not trigger a linter warning, so it's unclear to me how the code should be written:

[Reinmar]

[pomek]

Core DLL packages can import between themselves using any import condition.

• through the ckreditor5 package,
• an import from a package index.js,
• a direct import of required thing.

[pomek]

A rule to update:

https://github.com/ckeditor/eslint-plugin-ckeditor5-rules/blob/268126ecbed8e18b954cd4ba70cb816fae1ed97b/lib/rules/ckeditor-imports.js#L65-L68

[Reinmar]

There's a history behind the inconsistency. The problem is that core DLL packages may want to import something from another core DLL package that is not exposed in index.js (because we didn't want to make it a public API yet). So, at least some imports would have to use the @ckeditor/ckeditor5-.../src/ notation. Hence, all should.

Let's create a rule checking for that. And document the "why" briefly in the documentation introduced in #10051.

Finally, create a followup to check what kind of imports between core DLL packages block us from moving to index.js-based imports. NOTE: To make all imports in our code consistent, we'd need to use ckeditor/src/... notation, not @ckeditor/ckeditor5-foo notation. So, the fragment of code in my first comment was n fact not even consistent with that. See #10375 (comment)

[pomek]

PRs:

• Import between DLL packages must use the full name of the imported package eslint-plugin-ckeditor5-rules#7
• The Code style guide - mention imports between DLLs packages #10468

Finally, create a followup to check...

#10469