From e32fbe02102fe80db29f73c26496a40852032354 Mon Sep 17 00:00:00 2001
From: Bentley O'Kane-Chase <bentleyo@gmail.com>
Date: Wed, 23 Oct 2024 06:31:23 +1000
Subject: [PATCH] fix(vue): incorrect view rendered when using router.go(-n)
 (#29877)

resolves #28201

This PR fixes the navigation issue related to `router.go` that was
identified in issue #28201. After working on this issue I realised that
@xxllxhdj has already created a PR for this in #29847. While their fix
is great, I have added tests to replicate the issue, reused existing
code and `undefined` will be returned in unexpected situations - which
matches the existing functionality.

## What is the current behavior?

If a user navigates from `/home` -> `/pageA` -> `/pageB` -> `/pageC` ->
back to `/pageB` -> then `router.go(-2)` is called the URL will be
updated to `/home` correctly, but the app will try to render `/pageA`.

This happens for any delta < -1.

## What is the new behavior?

The app will correctly render `/pageA`, which matches the URL.

## Does this introduce a breaking change?

- [ ] Yes
- [X] No

---------

Co-authored-by: xxllxhdj <12881488+xxllxhdj@users.noreply.github.com>
---
 .../__tests__/locationHistory.spec.ts         | 21 +++++++++++++++++++
 packages/vue-router/src/locationHistory.ts    | 14 +++++--------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/packages/vue-router/__tests__/locationHistory.spec.ts b/packages/vue-router/__tests__/locationHistory.spec.ts
index fe7f94e723..196dcc75d8 100644
--- a/packages/vue-router/__tests__/locationHistory.spec.ts
+++ b/packages/vue-router/__tests__/locationHistory.spec.ts
@@ -84,4 +84,25 @@ describe('Location History', () => {
     expect(locationHistory.canGoBack(1, 0, 1)).toEqual(true);
     expect(locationHistory.canGoBack(2, 0, 1)).toEqual(false);
   });
+
+  it('should correctly find the last location', () => {
+    const [home, pageA, pageB, pageC] = [
+      { pathname: '/home' },
+      { pathname: '/page-a', pushedByRoute: '/home' },
+      { pathname: '/page-b', pushedByRoute: '/page-a' },
+      { pathname: '/page-c', pushedByRoute: '/page-b' },
+    ];
+
+    locationHistory.add(home);
+    locationHistory.add(pageA);
+    locationHistory.add(pageB);
+    locationHistory.add(pageC);
+
+    expect(locationHistory.findLastLocation(pageB)).toEqual(pageA);
+    expect(locationHistory.findLastLocation(pageB, -2)).toEqual(home);
+
+    expect(locationHistory.findLastLocation(pageC)).toEqual(pageB);
+    expect(locationHistory.findLastLocation(pageC, -2)).toEqual(pageA);
+    expect(locationHistory.findLastLocation(pageC, -3)).toEqual(home);
+  });
 });
diff --git a/packages/vue-router/src/locationHistory.ts b/packages/vue-router/src/locationHistory.ts
index f48499254e..9e12afd799 100644
--- a/packages/vue-router/src/locationHistory.ts
+++ b/packages/vue-router/src/locationHistory.ts
@@ -239,15 +239,11 @@ export const createLocationHistory = () => {
         }
       }
     }
-    if (delta < -1) {
-      return locationHistory[locationHistory.length - 1 + delta];
-    } else {
-      for (let i = locationHistory.length - 2; i >= 0; i--) {
-        const ri = locationHistory[i];
-        if (ri) {
-          if (ri.pathname === routeInfo.pushedByRoute) {
-            return ri;
-          }
+    for (let i = locationHistory.length - 2; i >= 0; i--) {
+      const ri = locationHistory[i];
+      if (ri) {
+        if (ri.pathname === routeInfo.pushedByRoute) {
+          return locationHistory[i + 1 + delta]
         }
       }
     }