Deleting the only app in a workspace makes CLI unusable

Current Behavior

Deleting all apps in the workspace leaves the CLI unusable. It fails with Project 'testapp' could not be found in workspace due to the app still being listed in the defaultProject property in angular.json

Expected Behavior

Deleting the app should not make the CLI fail.

Steps to Reproduce

• npx create-nx-workspace@latest
  • name: testtorg
  • application: angular
  • app name: testapp
  • styles: CSS
  • cloud: no
• cd testorg
• code .
• open nx Console tab in VSCode
• click Generate
• choose @nrwl/workspace - remove
  • enter projectName testapp-e2e and click “Run” (e2e app is deleted)
  • enter projectName testapp and click “Run” (app is deleted)
• close the Generate tab
• click Generate again
• choose @nrwl/angular - application
• terminal begins showing Project 'testapp' could not be found in workspace errors on all the dry run commands and any command you try to run (e.g. entering a name and clicking “Run” results in the same error
• CLI commands give the same error, e.g. nx g @nrwl/angular:app -> Project 'testapp' could not be found in workspace.

Failure Logs

Environment

[jdforsythe]

@FrozenPandaz I pushed PR #3528

Since updateWorkspace() was already being called, I just added the check and warning message there.

I also added tests.

[FrozenPandaz]

Removing it is fine.

👍 I think so as well though I think the user should be warned that they no longer have a defaultProject and they may want to define a new one.

If a user removes an app and has no angular.json file, one shouldn’t be created.

I think it is ensured that either a workspace.json or angular.json (getWorkspacePath identifies which one to update) exists in a workspace otherwise, there are errors thrown higher up. Those functions are also used in many other places so if there is an issue, it’s more wide-spread than within @nrwl/workspace:remove and can be addressed separately.