From c99619d823021763f9aab15e1a950ee2da582476 Mon Sep 17 00:00:00 2001
From: Chris Nguyen <cngu@users.noreply.github.com>
Date: Fri, 2 Nov 2018 10:06:18 -0600
Subject: [PATCH 1/3] Prevent users from invalidating the subscription iterator
 by synchronously calling unsubscribe

---
 src/store.js            |  2 +-
 test/unit/store.spec.js | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/store.js b/src/store.js
index 4251eaa73..77c5d3cba 100644
--- a/src/store.js
+++ b/src/store.js
@@ -100,7 +100,7 @@ export class Store {
         handler(payload)
       })
     })
-    this._subscribers.forEach(sub => sub(mutation, this.state))
+    this._subscribers.slice().forEach(sub => sub(mutation, this.state))
 
     if (
       process.env.NODE_ENV !== 'production' &&
diff --git a/test/unit/store.spec.js b/test/unit/store.spec.js
index 001ee4249..5a86be8a7 100644
--- a/test/unit/store.spec.js
+++ b/test/unit/store.spec.js
@@ -320,6 +320,27 @@ describe('Store', () => {
     expect(secondSubscribeSpy.calls.count()).toBe(2)
   })
 
+  it('subscribe: should handle subscriptions with synchronous unsubscriptions', () => {
+    const subscribeSpy = jasmine.createSpy()
+    const testPayload = 2
+    const store = new Vuex.Store({
+      state: {},
+      mutations: {
+        [TEST]: () => {}
+      }
+    })
+
+    const unsubscribe = store.subscribe(() => unsubscribe())
+    store.subscribe(subscribeSpy)
+    store.commit(TEST, testPayload)
+
+    expect(subscribeSpy).toHaveBeenCalledWith(
+      { type: TEST, payload: testPayload },
+      store.state
+    )
+    expect(subscribeSpy.calls.count()).toBe(1)
+  })
+
   // store.watch should only be asserted in non-SSR environment
   if (!isSSR) {
     it('strict mode: warn mutations outside of handlers', () => {

From e404657d778ecc2267cd4eed79d97c92b49a3523 Mon Sep 17 00:00:00 2001
From: Chris Nguyen <cnguyen@smarttech.com>
Date: Wed, 19 Dec 2018 23:07:13 -0700
Subject: [PATCH 2/3] Prevent users from invalidating the action subscription
 iterator by synchronously calling unsubscribe

---
 src/store.js            | 10 ++++++++--
 test/unit/store.spec.js | 21 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/store.js b/src/store.js
index 77c5d3cba..d57880034 100644
--- a/src/store.js
+++ b/src/store.js
@@ -100,7 +100,8 @@ export class Store {
         handler(payload)
       })
     })
-    this._subscribers.slice().forEach(sub => sub(mutation, this.state))
+
+    notifySubscribers(this._subscribers, mutation, this.state)
 
     if (
       process.env.NODE_ENV !== 'production' &&
@@ -129,7 +130,7 @@ export class Store {
       return
     }
 
-    this._actionSubscribers.forEach(sub => sub(action, this.state))
+    notifySubscribers(this._actionSubscribers, action, this.state)
 
     return entry.length > 1
       ? Promise.all(entry.map(handler => handler(payload)))
@@ -439,6 +440,11 @@ function registerGetter (store, type, rawGetter, local) {
   }
 }
 
+function notifySubscribers (subscribers, message, state) {
+  // create shallow copy to prevent iterator invalidation if users synchronously call unsubscribe
+  subscribers.slice().forEach(sub => sub(message, state))
+}
+
 function enableStrictMode (store) {
   store._vm.$watch(function () { return this._data.$$state }, () => {
     if (process.env.NODE_ENV !== 'production') {
diff --git a/test/unit/store.spec.js b/test/unit/store.spec.js
index 5a86be8a7..561496e60 100644
--- a/test/unit/store.spec.js
+++ b/test/unit/store.spec.js
@@ -341,6 +341,27 @@ describe('Store', () => {
     expect(subscribeSpy.calls.count()).toBe(1)
   })
 
+  it('subscribeAction: should handle subscriptions with synchronous unsubscriptions', () => {
+    const subscribeSpy = jasmine.createSpy()
+    const testPayload = 2
+    const store = new Vuex.Store({
+      state: {},
+      actions: {
+        [TEST]: () => {}
+      }
+    })
+
+    const unsubscribe = store.subscribeAction(() => unsubscribe())
+    store.subscribeAction(subscribeSpy)
+    store.dispatch(TEST, testPayload)
+
+    expect(subscribeSpy).toHaveBeenCalledWith(
+      { type: TEST, payload: testPayload },
+      store.state
+    )
+    expect(subscribeSpy.calls.count()).toBe(1)
+  })
+
   // store.watch should only be asserted in non-SSR environment
   if (!isSSR) {
     it('strict mode: warn mutations outside of handlers', () => {

From 9cddc8aa689e6cc44093566a6c781c416d1f8ec0 Mon Sep 17 00:00:00 2001
From: Chris Nguyen <cngu@users.noreply.github.com>
Date: Tue, 24 Dec 2019 20:37:07 -0700
Subject: [PATCH 3/3] Fix commit subscribers argument invocation

---
 src/store.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/store.js b/src/store.js
index d6a87a682..8b89d8187 100644
--- a/src/store.js
+++ b/src/store.js
@@ -104,7 +104,7 @@ export class Store {
 
     this._subscribers
       .slice() // shallow copy to prevent iterator invalidation if subscriber synchronously calls unsubscribe
-      .forEach(sub => sub(message, state))
+      .forEach(sub => sub(mutation, this.state))
 
     if (
       process.env.NODE_ENV !== 'production' &&