fix(router): should not create a route state if navigation is canceled (#12868)

Closes #12776

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

@@ -154,6 +154,9 @@ import {UrlSegment, UrlSegmentGroup} from './url_tree';
  * When navigating to `/team/11/user/jim`, the router will instantiate the wrapper component with
  * the user component in it.
  *
+ * An empty path route inherits its parent's params and data. This is because it cannot have its
+ * own params, and, as a result, it often uses its parent's params and data as its own.
+ *
  * ### Matching Strategy
  *
  * By default the router will look at what is left in the url, and check if it starts with
@@ -219,7 +222,8 @@ import {UrlSegment, UrlSegmentGroup} from './url_tree';
  * has to have the primary and aux outlets defined.
  *
  * The router will also merge the `params`, `data`, and `resolve` of the componentless parent into
- * the `params`, `data`, and `resolve` of the children.
+ * the `params`, `data`, and `resolve` of the children. This is done because there is no component
+ * that can inject the activated route of the componentless parent.
  *
  * This is especially useful when child components are defined as follows:
  *

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

@@ -623,7 +623,8 @@ export class Router {
       Promise.resolve()
           .then(
               (_) => this.runNavigate(
-                  url, rawUrl, false, false, id, createEmptyState(url, this.rootComponentType)))
+                  url, rawUrl, false, false, id,
+                  createEmptyState(url, this.rootComponentType).snapshot))
           .then(resolve, reject);
 
     } else {
@@ -634,7 +635,7 @@ export class Router {
 
   private runNavigate(
       url: UrlTree, rawUrl: UrlTree, shouldPreventPushState: boolean, shouldReplaceUrl: boolean,
-      id: number, precreatedState: RouterState): Promise<boolean> {
+      id: number, precreatedState: RouterStateSnapshot): Promise<boolean> {
     if (id !== this.navigationId) {
       this.location.go(this.urlSerializer.serialize(this.currentUrlTree));
       this.routerEvents.next(new NavigationCancel(
@@ -644,68 +645,80 @@ export class Router {
     }
 
     return new Promise((resolvePromise, rejectPromise) => {
-      let state: RouterState;
+      // create an observable of the url and route state snapshot
-      let navigationIsSuccessful: boolean;
+      // this operation do not result in any side effects
-      let preActivation: PreActivation;
+      let urlAndSnapshot$: Observable<{appliedUrl: UrlTree, snapshot: RouterStateSnapshot}>;
-
-      let appliedUrl: UrlTree;
-
-      const storedState = this.currentRouterState;
-      const storedUrl = this.currentUrlTree;
-
-      let routerState$: any;
-
       if (!precreatedState) {
         const redirectsApplied$ =
             applyRedirects(this.injector, this.configLoader, url, this.config);
 
-        const snapshot$ = mergeMap.call(redirectsApplied$, (u: UrlTree) => {
+        urlAndSnapshot$ = mergeMap.call(redirectsApplied$, (appliedUrl: UrlTree) => {
-          appliedUrl = u;
+          return map.call(
-          return recognize(
+              recognize(
-              this.rootComponentType, this.config, appliedUrl, this.serializeUrl(appliedUrl));
+                  this.rootComponentType, this.config, appliedUrl, this.serializeUrl(appliedUrl)),
-        });
+              (snapshot: any) => {
 
-        const emitRecognzied$ =
-            map.call(snapshot$, (newRouterStateSnapshot: RouterStateSnapshot) => {
                 this.routerEvents.next(new RoutesRecognized(
-                  id, this.serializeUrl(url), this.serializeUrl(appliedUrl),
+                    id, this.serializeUrl(url), this.serializeUrl(appliedUrl), snapshot));
-                  newRouterStateSnapshot));
-              return newRouterStateSnapshot;
-            });
 
-        routerState$ = map.call(emitRecognzied$, (routerStateSnapshot: RouterStateSnapshot) => {
+                return {appliedUrl, snapshot};
-          return createRouterState(routerStateSnapshot, this.currentRouterState);
+              });
         });
       } else {
-        appliedUrl = url;
+        urlAndSnapshot$ = of ({appliedUrl: url, snapshot: precreatedState});
-        routerState$ = of (precreatedState);
       }
 
-      const preactivation$ = map.call(routerState$, (newState: RouterState) => {
+
-        state = newState;
+      // run preactivation: guards and data resolvers
+      let preActivation: PreActivation;
+      const preactivationTraverse$ = map.call(urlAndSnapshot$, ({appliedUrl, snapshot}: any) => {
         preActivation =
-            new PreActivation(state.snapshot, this.currentRouterState.snapshot, this.injector);
+            new PreActivation(snapshot, this.currentRouterState.snapshot, this.injector);
         preActivation.traverse(this.outletMap);
+        return {appliedUrl, snapshot};
       });
 
-      const preactivation2$ = mergeMap.call(preactivation$, () => {
+      const preactivationCheckGuards =
+          mergeMap.call(preactivationTraverse$, ({appliedUrl, snapshot}: any) => {
             if (this.navigationId !== id) return of (false);
 
-        return preActivation.checkGuards();
+            return map.call(preActivation.checkGuards(), (shouldActivate: boolean) => {
+              return {appliedUrl: appliedUrl, snapshot: snapshot, shouldActivate: shouldActivate};
+            });
           });
 
-      const resolveData$ = mergeMap.call(preactivation2$, (shouldActivate: boolean) => {
+      const preactivationResolveData$ = mergeMap.call(preactivationCheckGuards, (p: any) => {
         if (this.navigationId !== id) return of (false);
 
-        if (shouldActivate) {
+        if (p.shouldActivate) {
-          return map.call(preActivation.resolveData(), () => shouldActivate);
+          return map.call(preActivation.resolveData(), () => p);
         } else {
-          return of (shouldActivate);
+          return of (p);
         }
       });
 
-      resolveData$
+
-          .forEach((shouldActivate: boolean) => {
+      // create router state
+      // this operation has side effects => route state is being affected
+      const routerState$ =
+          map.call(preactivationResolveData$, ({appliedUrl, snapshot, shouldActivate}: any) => {
+            if (shouldActivate) {
+              const state = createRouterState(snapshot, this.currentRouterState);
+              return {appliedUrl, state, shouldActivate};
+            } else {
+              return {appliedUrl, state: null, shouldActivate};
+            }
+          });
+
+
+      // applied the new router state
+      // this operation has side effects
+      let navigationIsSuccessful: boolean;
+      const storedState = this.currentRouterState;
+      const storedUrl = this.currentUrlTree;
+
+      routerState$
+          .forEach(({appliedUrl, state, shouldActivate}: any) => {
             if (!shouldActivate || id !== this.navigationId) {
               navigationIsSuccessful = false;
               return;
@@ -733,8 +746,8 @@ export class Router {
               () => {
                 this.navigated = true;
                 if (navigationIsSuccessful) {
-                  this.routerEvents.next(
+                  this.routerEvents.next(new NavigationEnd(
-                      new NavigationEnd(id, this.serializeUrl(url), this.serializeUrl(appliedUrl)));
+                      id, this.serializeUrl(url), this.serializeUrl(this.currentUrlTree)));
                   resolvePromise(true);
                 } else {
                   this.resetUrlToCurrentUrlTree();

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

@@ -1156,8 +1156,6 @@ describe('Integration', () => {
          advance(fixture);
          expect(location.path()).toEqual('/initial');
        })));
-
-    // should not break the back button when trigger by initial navigation
   });
 
   describe('guards', () => {
@@ -1380,6 +1378,11 @@ describe('Integration', () => {
                   return true;
                 }
               },
+              {
+                provide: 'alwaysFalse',
+                useValue:
+                    (c: any, a: ActivatedRouteSnapshot, b: RouterStateSnapshot) => { return false; }
+              },
             ]
           });
         });
@@ -1504,6 +1507,31 @@ describe('Integration', () => {
              advance(fixture);
              expect(location.path()).toEqual('/team/33/user/fedor');
            })));
+
+        it('should not create a route state if navigation is canceled',
+           fakeAsync(inject([Router, Location], (router: Router, location: Location) => {
+             const fixture = createRoot(router, RootCmp);
+
+             router.resetConfig([{
+               path: 'main',
+               component: TeamCmp,
+               children: [
+                 {path: 'component1', component: SimpleCmp, canDeactivate: ['alwaysFalse']},
+                 {path: 'component2', component: SimpleCmp}
+               ]
+             }]);
+
+             router.navigateByUrl('/main/component1');
+             advance(fixture);
+
+             router.navigateByUrl('/main/component2');
+             advance(fixture);
+
+             const teamCmp = fixture.debugElement.children[1].componentInstance;
+             expect(teamCmp.route.firstChild.url.value[0].path).toEqual('component1');
+             expect(location.path()).toEqual('/main/component1');
+           })));
+
       });
 
       describe('should work when given a class', () => {