[BUGFIX release] Avoid instantiation errors when app/router.js injects the router service.

packages/@ember/-internals/routing/lib/services/router.ts

@@ -5,27 +5,12 @@ import { assert } from '@ember/debug';
 import { readOnly } from '@ember/object/computed';
 import { assign } from '@ember/polyfills';
 import Service from '@ember/service';
-import { DEBUG } from '@glimmer/env';
 import { consumeTag, tagFor } from '@glimmer/validator';
-import { Transition } from 'router_js';
 import EmberRouter, { QueryParam } from '../system/router';
 import { extractRouteArgs, resemblesURL, shallowEqual } from '../utils';
 
 const ROUTER = symbol('ROUTER') as string;
 
-let freezeRouteInfo: Function;
-if (DEBUG) {
-  freezeRouteInfo = (transition: Transition) => {
-    if (transition.from !== null && !Object.isFrozen(transition.from)) {
-      Object.freeze(transition.from);
-    }
-
-    if (transition.to !== null && !Object.isFrozen(transition.to)) {
-      Object.freeze(transition.to);
-    }
-  };
-}
-
 function cleanURL(url: string, rootURL: string) {
   if (rootURL === '/') {
     return url;
@@ -73,31 +58,9 @@ export default class RouterService extends Service {
     }
     const owner = getOwner(this) as Owner;
     router = owner.lookup('router:main') as EmberRouter;
-    router.setupRouter();
     return (this[ROUTER] = router);
   }
 
-  constructor(owner: Owner) {
-    super(owner);
-
-    const router = owner.lookup('router:main') as EmberRouter;
-
-    router.on('routeWillChange', (transition: Transition) => {
-      if (DEBUG) {
-        freezeRouteInfo(transition);
-      }
-      this.trigger('routeWillChange', transition);
-    });
-
-    router.on('routeDidChange', (transition: Transition) => {
-      if (DEBUG) {
-        freezeRouteInfo(transition);
-      }
-
-      this.trigger('routeDidChange', transition);
-    });
-  }
-
   /**
      Transition the application into another route. The route may
      be either a single route or route path:

packages/@ember/-internals/routing/lib/system/router.ts

@@ -3,6 +3,7 @@ import { OutletState as GlimmerOutletState, OutletView } from '@ember/-internals
 import { computed, get, notifyPropertyChange, set } from '@ember/-internals/metal';
 import { FactoryClass, getOwner, Owner } from '@ember/-internals/owner';
 import { BucketCache } from '@ember/-internals/routing';
+import RouterService from '@ember/-internals/routing/lib/services/router';
 import { A as emberA, Evented, Object as EmberObject, typeOf } from '@ember/-internals/runtime';
 import Controller from '@ember/controller';
 import { assert, deprecate, info } from '@ember/debug';
@@ -23,6 +24,7 @@ import Route, {
   ROUTER_EVENT_DEPRECATIONS,
 } from './route';
 import RouterState from './router_state';
+
 /**
 @module @ember/routing
 */
@@ -78,6 +80,19 @@ function defaultWillTransition(
   }
 }
 
+let freezeRouteInfo: Function;
+if (DEBUG) {
+  freezeRouteInfo = (transition: Transition) => {
+    if (transition.from !== null && !Object.isFrozen(transition.from)) {
+      Object.freeze(transition.from);
+    }
+
+    if (transition.to !== null && !Object.isFrozen(transition.to)) {
+      Object.freeze(transition.to);
+    }
+  };
+}
+
 interface RenderOutletState {
   name: string;
   outlet: string;
@@ -146,6 +161,7 @@ class EmberRouter extends EmberObject {
   _handledErrors = new Set();
   _engineInstances: { [name: string]: { [id: string]: EngineInstance } } = Object.create(null);
   _engineInfoByRoute = Object.create(null);
+  _routerService: RouterService | undefined;
 
   _slowTransitionTimer: unknown;
 
@@ -156,6 +172,7 @@ class EmberRouter extends EmberObject {
     if (owner) {
       this.namespace = owner.lookup('application:main');
       this._bucketCache = owner.lookup(P`-bucket-cache:main`);
+      this._routerService = owner.lookup('service:router');
     }
   }
 
@@ -286,6 +303,12 @@ class EmberRouter extends EmberObject {
 
       routeWillChange(transition: Transition) {
         router.trigger('routeWillChange', transition);
+        if (router._routerService) {
+          if (DEBUG) {
+            freezeRouteInfo(transition);
+          }
+          router._routerService.trigger('routeWillChange', transition);
+        }
         // in case of intermediate transition we update the current route
         // to make router.currentRoute.name consistent with router.currentRouteName
         // see https://github.com/emberjs/ember.js/issues/19449
@@ -298,6 +321,12 @@ class EmberRouter extends EmberObject {
         router.set('currentRoute', transition.to);
         once(() => {
           router.trigger('routeDidChange', transition);
+          if (router._routerService) {
+            if (DEBUG) {
+              freezeRouteInfo(transition);
+            }
+            router._routerService.trigger('routeDidChange', transition);
+          }
         });
       }
 

packages/ember/tests/routing/router_service_test/basic_test.js

@@ -1,6 +1,7 @@
 import { Route, NoneLocation } from '@ember/-internals/routing';
 import { set } from '@ember/-internals/metal';
 import { RouterTestCase, moduleFor } from 'internal-test-helpers';
+import { inject as injectService } from '@ember/service';
 
 moduleFor(
   'Router Service - main',
@@ -150,5 +151,20 @@ moduleFor(
         assert.ok(location instanceof NoneLocation);
       });
     }
+
+    ['@test RouterService can be injected into router and accessed on init'](assert) {
+      assert.expect(1);
+
+      this.router.reopen({
+        routerService: injectService('router'),
+        init() {
+          this.routerService.one('routeDidChange', () => {
+            assert.ok(true, 'routeDidChange event listener called');
+          });
+        },
+      });
+
+      return this.visit('/');
+    }
   }
 );

packages/ember/tests/routing/router_service_test/non_application_test_test.js

@@ -47,19 +47,36 @@ moduleFor(
       assert.expect(5);
       assert.equal(this.routerService.get('currentRouteName'), null);
       assert.equal(this.routerService.get('currentURL'), null);
+      assert.equal(this.routerService.get('location'), 'none');
+      assert.equal(this.routerService.get('rootURL'), '/');
+      assert.equal(this.routerService.get('currentRoute'), null);
+    }
+
+    ['@test RouterService properties of router can be accessed with default when router is present'](
+      assert
+    ) {
+      assert.expect(5);
+      let router = this.owner.lookup('router:main');
+      router.setupRouter();
+      assert.equal(this.routerService.get('currentRouteName'), null);
+      assert.equal(this.routerService.get('currentURL'), null);
       assert.ok(this.routerService.get('location') instanceof NoneLocation);
       assert.equal(this.routerService.get('rootURL'), '/');
       assert.equal(this.routerService.get('currentRoute'), null);
     }
 
     ['@test RouterService#urlFor returns url'](assert) {
+      let router = this.owner.lookup('router:main');
+      router.setupRouter();
       assert.equal(this.routerService.urlFor('parent.child'), '/child');
     }
 
     ['@test RouterService#transitionTo with basic route'](assert) {
       assert.expect(2);
 
       let componentInstance;
+      let router = this.owner.lookup('router:main');
+      router.setupRouter();
 
       this.addTemplate('parent.index', '{{foo-bar}}');
 
@@ -90,6 +107,8 @@ moduleFor(
     }
 
     ['@test RouterService#recognize recognize returns routeInfo'](assert) {
+      let router = this.owner.lookup('router:main');
+      router.setupRouter();
       let routeInfo = this.routerService.recognize('/dynamic-with-child/123/1?a=b');
       assert.ok(routeInfo);
       let { name, localName, parent, child, params, queryParams, paramNames } = routeInfo;