Solution style tsconfig impact in Angular 10

[alan-agius4]

Use Cases

In TypeScript 3.9, the concept of solutions style tsconfig was introduced, in Angular we saw the potentiation and possibility of fixing long outstanding issues such as incorrectly having test typings in components files. In Angular CLI version 10 we adopted scaffolded new and migrated existing workspaces to use solution-style Typescript configuration.

After Angular version 10 stable was rolled out to the community, we received more feedback about this and previously unforeseen consequences of using this feature.

• Unreferenced files don’t inherit compiler options which results in errors or lack of them New "Solution Style" tsconfig.json file breaks the unused files in most Editors angular/angular-cli#18040 & Provide way to configure default compiler options for TS Server Inferred Project #39689
• Unreferenced files cannot be automatically imported Issues with importing interfaces created with export interface in Angular and TypeScript 3.9.6 angular/angular-cli#18170 & Typescript auto-complete not working in VSCode #39370
• TS Server is slow to respond when having a large number of references Solution style tsconfig - TS Server is slow to respond when having a large number of references #39144

Suggestion

We have put together a document that goes a bit in more detail about these issues and also possible actions and solutions.

We'd like to share this document with you: https://docs.google.com/document/d/1eB6cGCG_2ircfS5GzpDC9dBgikeYYcMxghVH5sDESHw/edit?usp=sharing

If you have any questions, feel free to ping me here or in #ts-core slack channel.

Thank you.

//cc @kyliau

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Edit: From the TS team, we'd like a confirmation and any recommandations they might have on the proposed changes that we'd like to introduce in our projects and if creating auxiliary programs to address the auto-import issue is something that will be considered.

[sheetalkamat]

1. Unreferenced files don’t inherit compiler options
2. Unreferenced files cannot be automatically imported
   While we can fix this problem by adding more complex globbing in the spec and server TypeScript configuration files, we feel that it would best that this is tackled upstream.

For unreferenced files and its auto import not working i think the main issue is that there is no clear way to tell which project this new file should belong to.. Auxiliary program is not going to help because it helps with files from package json but here user is adding new file to their app/spec/test program.
The best way to solve this is to have three separate folders for spec, app and test so the files will be added to correct project irrespective of name. If thats not something that works for compatibility or other reasons, globbing to exclude and include everything else is much better than listing files to include so that new files will get included in correct program.

The proposed change is to move away from a single workspace level solution style tsconfig and add a project level solutions style tsconfig.

Definitely recommend this since its much cleaner and will not have to include world /load world to know where the file should belong and what to do with it.
Having said that if you think its loading multiple project where it shouldn't have, i recommend creating issue with logs and repro steps to investigate that.