fix(router): parent resolve should complete before merging resolved data

Closes #12032

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

@@ -13,6 +13,7 @@ import {Subject} from 'rxjs/Subject';
 import {Subscription} from 'rxjs/Subscription';
 import {from} from 'rxjs/observable/from';
 import {of } from 'rxjs/observable/of';
+import {concatMap} from 'rxjs/operator/concatMap';
 import {every} from 'rxjs/operator/every';
 import {map} from 'rxjs/operator/map';
 import {mergeAll} from 'rxjs/operator/mergeAll';
@@ -692,7 +693,7 @@ export class PreActivation {
   resolveData(): Observable<any> {
     if (this.checks.length === 0) return of (null);
     const checks$ = from(this.checks);
-    const runningChecks$ = mergeMap.call(checks$, (s: any) => {
+    const runningChecks$ = concatMap.call(checks$, (s: any) => {
       if (s instanceof CanActivate) {
         return this.runResolve(s.route);
       } else {

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

@@ -48,6 +48,23 @@ describe('Router', () => {
       });
     });
 
+    it('should wait for the parent resolve to complete', () => {
+      const parentResolve = new InheritedResolve(InheritedResolve.empty, {data: 'resolver'});
+      const childResolve = new InheritedResolve(parentResolve, {});
+
+      const parent = createActivatedRouteSnapshot('a', {resolve: parentResolve});
+      const child = createActivatedRouteSnapshot('b', {resolve: childResolve});
+
+      const s = new RouterStateSnapshot(
+          'url', new TreeNode(empty.root, [new TreeNode(parent, [new TreeNode(child, [])])]));
+
+      const inj = {get: (token: any) => () => Promise.resolve(`${token}_value`)};
+
+      checkResolveData(s, empty, inj, () => {
+        expect(s.root.firstChild.firstChild.data).toEqual({data: 'resolver_value'});
+      });
+    });
+
     it('should copy over data when creating a snapshot', () => {
       const r1 = new InheritedResolve(InheritedResolve.empty, {data: 'resolver1'});
       const r2 = new InheritedResolve(InheritedResolve.empty, {data: 'resolver2'});