From 0aac59464d3f932d6b259abd5879a12ddd71d38b Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Wed, 9 Oct 2019 13:32:19 -0500
Subject: [PATCH 1/3] Update to use a historyId to track invalid popstates

---
 .../next/next-server/lib/router/router.ts     | 31 +++++++++++--------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/packages/next/next-server/lib/router/router.ts b/packages/next/next-server/lib/router/router.ts
index 7735dd9de2f42..3024374889f01 100644
--- a/packages/next/next-server/lib/router/router.ts
+++ b/packages/next/next-server/lib/router/router.ts
@@ -71,6 +71,7 @@ export default class Router implements BaseRouter {
   _bps: BeforePopStateCallback | undefined
   events: MittEmitter
   _wrapApp: (App: ComponentType) => any
+  historyId: number
 
   static events: MittEmitter = mitt()
 
@@ -126,6 +127,8 @@ export default class Router implements BaseRouter {
     this.sub = subscription
     this.clc = null
     this._wrapApp = wrapApp
+    // we use a historyId to enable ignoring invalid popstates
+    this.historyId = new Date().getTime()
 
     if (typeof window !== 'undefined') {
       // in order for `e.state` to work on the `onpopstate` event
@@ -137,17 +140,6 @@ export default class Router implements BaseRouter {
       )
 
       window.addEventListener('popstate', this.onPopState)
-      window.addEventListener('unload', () => {
-        // Workaround for popstate firing on initial page load when
-        // navigating back from an external site
-        if (history.state) {
-          const { url, as, options }: any = history.state
-          this.changeState('replaceState', url, as, {
-            ...options,
-            fromExternal: true,
-          })
-        }
-      })
     }
   }
 
@@ -176,9 +168,11 @@ export default class Router implements BaseRouter {
       return
     }
 
+    console.log(e.state.options.historyId, this.historyId)
+
     // Make sure we don't re-render on initial load,
     // can be caused by navigating back from an external site
-    if (e.state.options && e.state.options.fromExternal) {
+    if (e.state.options && e.state.options.historyId !== this.historyId) {
       return
     }
 
@@ -379,7 +373,18 @@ export default class Router implements BaseRouter {
 
     if (method !== 'pushState' || getURL() !== as) {
       // @ts-ignore method should always exist on history
-      window.history[method]({ url, as, options }, null, as)
+      window.history[method](
+        {
+          url,
+          as,
+          options: {
+            ...options,
+            historyId: this.historyId,
+          },
+        },
+        null,
+        as
+      )
     }
   }
 

From 005eb67ab1ad80a7eb346a47b0c3f9cb9ac1ace0 Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Thu, 10 Oct 2019 05:48:36 -0500
Subject: [PATCH 2/3] Remove log from debugging

---
 packages/next/next-server/lib/router/router.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/next/next-server/lib/router/router.ts b/packages/next/next-server/lib/router/router.ts
index 3024374889f01..d7d4e99bbc9ed 100644
--- a/packages/next/next-server/lib/router/router.ts
+++ b/packages/next/next-server/lib/router/router.ts
@@ -168,8 +168,6 @@ export default class Router implements BaseRouter {
       return
     }
 
-    console.log(e.state.options.historyId, this.historyId)
-
     // Make sure we don't re-render on initial load,
     // can be caused by navigating back from an external site
     if (e.state.options && e.state.options.historyId !== this.historyId) {

From aec294ec846ba29a6b4e7ef897f3df7e1ea5cbac Mon Sep 17 00:00:00 2001
From: JJ Kasper <jj@jjsweb.site>
Date: Thu, 10 Oct 2019 09:29:49 -0500
Subject: [PATCH 3/3] Use Math.random instead of Date.getTime to avoid mocks

---
 packages/next/next-server/lib/router/router.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/next/next-server/lib/router/router.ts b/packages/next/next-server/lib/router/router.ts
index d7d4e99bbc9ed..8339ea21b8d79 100644
--- a/packages/next/next-server/lib/router/router.ts
+++ b/packages/next/next-server/lib/router/router.ts
@@ -128,7 +128,7 @@ export default class Router implements BaseRouter {
     this.clc = null
     this._wrapApp = wrapApp
     // we use a historyId to enable ignoring invalid popstates
-    this.historyId = new Date().getTime()
+    this.historyId = Math.random()
 
     if (typeof window !== 'undefined') {
       // in order for `e.state` to work on the `onpopstate` event