fix(angular): back button goes back to proper tab (#18005)

fixes #17278 
fixes #15216

Author: liamdebeasi

angular/src/directives/navigation/stack-controller.ts

@@ -101,7 +101,23 @@ export class StackController {
         return Promise.resolve(false);
       }
       const view = views[views.length - deep - 1];
-      return this.navCtrl.navigateBack(view.url).then(() => true);
+      let url = view.url;
+
+      const viewSavedData = view.savedData;
+      if (viewSavedData) {
+        const primaryOutlet = viewSavedData.get('primary');
+        if (
+          primaryOutlet &&
+          primaryOutlet.route &&
+          primaryOutlet.route._routerState &&
+          primaryOutlet.route._routerState.snapshot &&
+          primaryOutlet.route._routerState.snapshot.url
+        ) {
+          url = primaryOutlet.route._routerState.snapshot.url;
+        }
+      }
+
+      return this.navCtrl.navigateBack(url).then(() => true);
     });
   }
 

angular/test/test-app/e2e/src/tabs.e2e-spec.ts

@@ -130,6 +130,25 @@ describe('tabs', () => {
       expect(await tab.$('ion-back-button').isDisplayed()).toBe(false);
     });
   });
+  
+  describe('enter url - /tabs/contact/one', () => {
+    beforeEach(async () => {
+      await browser.get('/tabs/contact/one');
+    });
+    
+    it('should return to correct tab after going to page in different outlet', async () => {      
+      const tab = await getSelectedTab();
+      await tab.$('#goto-nested-page1').click();
+            
+      await testStack('app-nested-outlet ion-router-outlet', ['app-nested-outlet-page']);
+      
+      const nestedOutlet = await element(by.css('app-nested-outlet'));
+      const backButton = await nestedOutlet.$('ion-back-button');
+      await backButton.click();
+            
+      await testTabTitle('Tab 2 - Page 1');
+    });
+  })
 });
 
 async function testState(count: number, tab: string) {

angular/test/test-app/src/app/nested-outlet/nested-outlet.component.html

@@ -1,5 +1,8 @@
 <ion-header>
   <ion-toolbar>
+    <ion-buttons slot="start">
+      <ion-back-button></ion-back-button>
+    </ion-buttons>
     <ion-title>
       NESTED OUTLET
     </ion-title>

angular/test/test-app/src/app/tabs-tab2/tabs-tab2.component.html

@@ -9,5 +9,6 @@ <h1>Welcome to Tab 2</h1>
   <p>
     <ion-button routerLink="/tabs/account" id="goto-tab1-page1">Go to Tab 1 - Page 1</ion-button>
     <ion-button routerLink="/tabs/account/nested/12" id="goto-tab1-page2">Go to Tab 1 - Page 2</ion-button>
+    <ion-button routerLink="/nested-outlet/page" id="goto-nested-page1">Go to nested</ion-button>
   </p>
 </ion-content>