Version info

Angular: 12.2.0

Firebase: latest

AngularFire: latest

Other (e.g. Ionic/Cordova, Node, browser, operating system):

How to reproduce these conditions

This can be easily reproduced in Nx by following these steps, but would occur in a regular Angular project if the angular.json file had a similar project configuration to below. Reproduction steps for Nx are found in the Issue mention, for angular just ng new and update the configuration.

Debug output

** Screenshots **

Expected behavior

ng add @angular/fire passes if sourceRoot and root are both relative to the workspace root

Actual behavior

ng add @angular/fire only passes if sourceRoot is relative to root

In a workspace with a project configured as below, ng add @angular/fire fails due to the sourceRoot path being appended to the root, rather than replacing it.

{ "root": "apps/admin" "sourceRoot": "apps/admin/src" }

Maybe this portion of code could use something like

const sourcePath = project.sourceRoot?.startsWith(project.root)	? project.sourceRoot	: [project.root, project.sourceRoot].filter(it => !!it).join('/'); 

I'd be happy to put in a PR to make the change if its agreed upon.