fix(vue): back button now selects correct route when navigating from view multiple times (#24060)

resolves #23987

Author: liamdebeasi

packages/vue-router/src/locationHistory.ts

@@ -105,11 +105,15 @@ export const createLocationHistory = () => {
 
   const size = () => locationHistory.length;
 
-  const updateByHistoryPosition = (routeInfo: RouteInfo) => {
+  const updateByHistoryPosition = (routeInfo: RouteInfo, updateEntries: boolean) => {
     const existingRouteIndex = locationHistory.findIndex(r => r.position === routeInfo.position);
     if (existingRouteIndex === -1) return;
 
     locationHistory[existingRouteIndex].pathname = routeInfo.pathname;
+
+    if (updateEntries) {
+      locationHistory[existingRouteIndex].pushedByRoute = routeInfo.pushedByRoute;
+    }
   }
 
   /**

packages/vue-router/src/router.ts

@@ -275,7 +275,23 @@ export const createIonRouter = (opts: IonicVueRouterOptions, router: Router) =>
        * new items within the stack.
        */
       if (historySize > historyDiff && routeInfo.tab === undefined) {
-        locationHistory.updateByHistoryPosition(routeInfo);
+        /**
+         * When going from /a --> /a/1 --> /b, then going
+         * back to /a, then going /a --> /a/2 --> /b, clicking
+         * the ion-back-button should return us to /a/2, not /a/1.
+         * However, since the route entry for /b already exists,
+         * we need to update other information such as the "pushedByRoute"
+         * so we know which route pushed this new route.
+         *
+         * However, when using router.go with a stride of >1 or <-1,
+         * we should not update this additional information because
+         * we are traversing through the history, not pushing new states.
+         * Going from /a --> /b --> /c, then doing router.go(-2), then doing
+         * router.go(2) to go from /a --> /c should not update the route
+         * listing to say that /c was pushed by /a.
+         */
+        const hasDeltaStride = delta !== undefined && Math.abs(delta) !== 1;
+        locationHistory.updateByHistoryPosition(routeInfo, !hasDeltaStride);
       } else {
         locationHistory.add(routeInfo);
       }

packages/vue/test-app/tests/e2e/specs/routing.js

@@ -316,6 +316,51 @@ describe('Routing', () => {
     cy.ionPageDoesNotExist('routing');
     cy.ionPageDoesNotExist('routingparameter');
   })
+
+  // Verifies fix for https://github.com/ionic-team/ionic-framework/issues/23987
+  it('should choose correct view when navigating back', () => {
+    cy.visit('http://localhost:8080');
+
+    cy.routerPush('/routing');
+    cy.ionPageVisible('routing');
+    cy.ionPageHidden('home');
+
+    cy.routerPush('/routing/123/view');
+    cy.ionPageVisible('routingparameterview');
+    cy.ionPageHidden('routing');
+
+    cy.routerPush('/routing/child');
+    cy.ionPageVisible('routingchild');
+    cy.ionPageHidden('routing');
+
+    cy.ionBackClick('routingchild');
+    cy.ionPageVisible('routingparameterview');
+    cy.ionPageDoesNotExist('routingchild');
+
+    cy.ionBackClick('routingparameterview');
+    cy.ionPageVisible('routing');
+    cy.ionPageDoesNotExist('routingparameterview');
+
+    cy.ionBackClick('routing');
+    cy.ionPageVisible('home');
+    cy.ionPageDoesNotExist('routing');
+
+    cy.routerPush('/routing');
+    cy.ionPageVisible('routing');
+    cy.ionPageHidden('home');
+
+    cy.routerPush('/routing/456/view');
+    cy.ionPageVisible('routingparameterview');
+    cy.ionPageHidden('routing');
+
+    cy.routerPush('/routing/child');
+    cy.ionPageVisible('routingchild');
+    cy.ionPageHidden('routing');
+
+    cy.ionBackClick('routingchild');
+    cy.ionPageVisible('routingparameterview');
+    cy.ionPageDoesNotExist('routingchild');
+  })
 });
 
 describe('Routing - Swipe to Go Back', () => {