feat(Router): call resolver when upstream params change (#12942)

With this change the resolver is called when the parameter for the activated and any parent routes change.
ie, switching from `/teams/10/players/5` to `/teams/12/players/5` will now trigger any `PlayerResolver`.

modules/@angular/router/src/router_state.ts

@@ -356,5 +356,9 @@ export function advanceActivatedRoute(route: ActivatedRoute): void {
 
 export function equalParamsAndUrlSegments(
     a: ActivatedRouteSnapshot, b: ActivatedRouteSnapshot): boolean {
-  return shallowEqual(a.params, b.params) && equalSegments(a.url, b.url);
-}
+  const equalUrlParams = shallowEqual(a.params, b.params) && equalSegments(a.url, b.url);
+  const parentsMismatch = !a.parent !== !b.parent;
+
+  return equalUrlParams && !parentsMismatch &&
+      (!a.parent || equalParamsAndUrlSegments(a.parent, b.parent));
+}

modules/@angular/router/test/router_state.spec.ts

@@ -100,9 +100,28 @@ describe('RouterState & Snapshot', () => {
 
   describe('equalParamsAndUrlSegments', () => {
     function createSnapshot(params: Params, url: UrlSegment[]): ActivatedRouteSnapshot {
-      return new ActivatedRouteSnapshot(
+      const snapshot = new ActivatedRouteSnapshot(
           url, params, <any>null, <any>null, <any>null, <any>null, <any>null, <any>null, <any>null,
           -1, null);
+      snapshot._routerState = new RouterStateSnapshot('', new TreeNode(snapshot, []));
+      return snapshot;
+    }
+
+    function createSnapshotPairWithParent(
+        params: [Params, Params], parentParams: [Params, Params],
+        urls: [string, string]): [ActivatedRouteSnapshot, ActivatedRouteSnapshot] {
+      const snapshot1 = createSnapshot(params[0], []);
+      const snapshot2 = createSnapshot(params[1], []);
+
+      const snapshot1Parent = createSnapshot(parentParams[0], [new UrlSegment(urls[0], {})]);
+      const snapshot2Parent = createSnapshot(parentParams[1], [new UrlSegment(urls[1], {})]);
+
+      snapshot1._routerState =
+          new RouterStateSnapshot('', new TreeNode(snapshot1Parent, [new TreeNode(snapshot1, [])]));
+      snapshot2._routerState =
+          new RouterStateSnapshot('', new TreeNode(snapshot2Parent, [new TreeNode(snapshot2, [])]));
+
+      return [snapshot1, snapshot2];
     }
 
     it('should return false when params are different', () => {
@@ -123,6 +142,27 @@ describe('RouterState & Snapshot', () => {
                  createSnapshot({a: 1}, [new UrlSegment('a', {})])))
           .toEqual(true);
     });
+
+    it('should return false when upstream params are different', () => {
+      const [snapshot1, snapshot2] =
+          createSnapshotPairWithParent([{a: 1}, {a: 1}], [{b: 1}, {c: 1}], ['a', 'a']);
+
+      expect(equalParamsAndUrlSegments(snapshot1, snapshot2)).toEqual(false);
+    });
+
+    it('should return false when upstream urls are different', () => {
+      const [snapshot1, snapshot2] =
+          createSnapshotPairWithParent([{a: 1}, {a: 1}], [{b: 1}, {b: 1}], ['a', 'b']);
+
+      expect(equalParamsAndUrlSegments(snapshot1, snapshot2)).toEqual(false);
+    });
+
+    it('should return true when upstream urls and params are equal', () => {
+      const [snapshot1, snapshot2] =
+          createSnapshotPairWithParent([{a: 1}, {a: 1}], [{b: 1}, {b: 1}], ['a', 'a']);
+
+      expect(equalParamsAndUrlSegments(snapshot1, snapshot2)).toEqual(true);
+    });
   });
 
   describe('advanceActivatedRoute', () => {
@@ -135,9 +175,12 @@ describe('RouterState & Snapshot', () => {
       const queryParams = {};
       const fragment = '';
       const data = {};
-      return new ActivatedRouteSnapshot(
+      const snapshot = new ActivatedRouteSnapshot(
           url, params, queryParams, fragment, data, <any>null, <any>null, <any>null, <any>null, -1,
           null);
+      const state = new RouterStateSnapshot('', new TreeNode(snapshot, []));
+      snapshot._routerState = state;
+      return snapshot;
     }
 
     it('should call change observers', () => {