fix(router): Do not clear currentNavigation if already set to next one (

#43852)

Experimentation with the Router URL management exposed a situation where
the `currentNavigation` was being cleared in the `finalize` after the
`currentNavigation` was already set to the next one.

This change ensures that the `currentNavigation` is only cleared if the
id of the finalized transition matches the one on the
`currentNavigation` object.

PR Close #43852

packages/router/src/router.ts

@@ -923,10 +923,11 @@ export class Router {
                              t.id} is not equal to the current navigation id ${this.navigationId}`;
                          this.cancelNavigationTransition(t, cancelationReason);
                        }
-                       // currentNavigation should always be reset to null here. If navigation was
-                       // successful, lastSuccessfulTransition will have already been set. Therefore
-                       // we can safely set currentNavigation to null here.
-                       this.currentNavigation = null;
+                       // Only clear current navigation if it is still set to the one that
+                       // finalized.
+                       if (this.currentNavigation?.id === t.id) {
+                         this.currentNavigation = null;
+                       }
                      }),
                      catchError((e) => {
                        // TODO(atscott): The NavigationTransition `t` used here does not accurately

packages/router/test/integration.spec.ts

@@ -1310,6 +1310,31 @@ describe('Integration', () => {
          expect(fixture.nativeElement.innerHTML).toContain('simple');
          expect(location.urlChanges).toEqual(['hash: /blocked']);
        }));
+
+    it('should accurately track currentNavigation', fakeAsync(() => {
+         const router = TestBed.inject(Router);
+         router.resetConfig([
+           {path: 'one', component: SimpleCmp, canActivate: ['in1Second']},
+           {path: 'two', component: BlankCmp, canActivate: ['in1Second']},
+         ]);
+
+         router.events.subscribe((e) => {
+           if (e instanceof NavigationStart) {
+             if (e.url === '/one') {
+               router.navigateByUrl('two');
+             }
+             router.events.subscribe((e) => {
+               if (e instanceof GuardsCheckEnd) {
+                 expect(router.getCurrentNavigation()?.extractedUrl.toString()).toEqual('/two');
+                 expect(router.getCurrentNavigation()?.extras).toBeDefined();
+               }
+             });
+           }
+         });
+
+         router.navigateByUrl('one');
+         tick(1000);
+       }));
   });
 
   it('should support secondary routes', fakeAsync(inject([Router], (router: Router) => {