Backport fix for #19004: RouterService#isActive() now consumes currentURL to 3.20

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

@@ -3,6 +3,7 @@ import { assert } from '@ember/debug';
 import { readOnly } from '@ember/object/computed';
 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';
@@ -308,6 +309,18 @@ export default class RouterService extends Service {
     let { routeName, models, queryParams } = extractRouteArgs(args);
     let routerMicrolib = this._router._routerMicrolib;
 
+    // When using isActive() in a getter, we want to entagle with the auto-tracking system
+    // for example,
+    // in
+    // get isBarActive() {
+    //   return isActive('foo.bar');
+    // }
+    //
+    // you'd expect isBarActive to be dirtied when the route changes.
+    //
+    // https://github.com/emberjs/ember.js/issues/19004
+    consumeTag(tagFor(this._router, 'currentURL'));
+
     // UNSAFE: casting `routeName as string` here encodes the existing
     // assumption but may be wrong: `extractRouteArgs` correctly returns it as
     // `string | undefined`. There may be bugs if `isActiveIntent` does

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

@@ -1,5 +1,6 @@
 import Controller from '@ember/controller';
 import { RouterTestCase, moduleFor } from 'internal-test-helpers';
+import Service, { inject as service } from '@ember/service';
 
 moduleFor(
   'Router Service - isActive',
@@ -33,6 +34,42 @@ moduleFor(
         });
     }
 
+    async ['@test RouterService#isActive entangles with route transitions'](assert) {
+      assert.expect(6);
+
+      this.add(
+        `service:foo`,
+        class extends Service {
+          @service router;
+
+          get isChildActive() {
+            return this.router.isActive('parent.child');
+          }
+
+          get isSisterActive() {
+            return this.router.isActive('parent.sister');
+          }
+        }
+      );
+
+      await this.visit('/');
+
+      let fooService = this.applicationInstance.lookup('service:foo');
+
+      assert.equal(fooService.isChildActive, false);
+      assert.equal(fooService.isSisterActive, false);
+
+      await this.routerService.transitionTo('parent.child');
+
+      assert.equal(fooService.isChildActive, true);
+      assert.equal(fooService.isSisterActive, false);
+
+      await this.routerService.transitionTo('parent.sister');
+
+      assert.equal(fooService.isChildActive, false);
+      assert.equal(fooService.isSisterActive, true);
+    }
+
     ['@test RouterService#isActive does not eagerly instantiate controller for query params'](
       assert
     ) {