From 6209102bd7ad40b85add40b04d140a939fcdeb2a Mon Sep 17 00:00:00 2001
From: "Filipe T. Amaral" <filipetamaral@gmail.com>
Date: Thu, 24 Jan 2019 23:30:01 -0200
Subject: [PATCH 1/2] fix(transition): Explicitly disable appear

The @appear hook is being invoked when appear is not specified or is falsy. This change make it
possible to dynamically disable it by setting :appear="false" when needed.
---
 .../web/runtime/components/transition.js      | 17 ++++++++++---
 .../features/transition/transition.spec.js    | 24 +++++++++++++++++++
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/platforms/web/runtime/components/transition.js b/src/platforms/web/runtime/components/transition.js
index 84fe82984a1..0901fc304d7 100644
--- a/src/platforms/web/runtime/components/transition.js
+++ b/src/platforms/web/runtime/components/transition.js
@@ -40,6 +40,15 @@ function getRealChild (vnode: ?VNode): ?VNode {
   }
 }
 
+function isAttrDisabled (k: string): boolean {
+  var data: Object = this;
+  const attr = data[camelize(k)]
+  return typeof attr == "undefined" ||
+         typeof attr !== "undefined" &&
+         (typeof attr === "boolean" && attr ||
+          typeof attr === "string" && attr == "false")
+}
+
 export function extractTransitionData (comp: Component): Object {
   const data = {}
   const options: ComponentOptions = comp.$options
@@ -49,9 +58,11 @@ export function extractTransitionData (comp: Component): Object {
   }
   // events.
   // extract listeners and pass them directly to the transition methods
-  const listeners: ?Object = options._parentListeners
-  for (const key in listeners) {
-    data[camelize(key)] = listeners[key]
+  const listeners: Object = options._parentListeners || {}
+  // remove the listeners that are explicitily disabled
+  const listenerKeys: Array<string> = Object.keys(listeners).filter(isAttrDisabled, data)
+  for (let i = 0; i < listenerKeys.length; i++) {
+    data[camelize(listenerKeys[i])] = listeners[listenerKeys[i]]
   }
   return data
 }
diff --git a/test/unit/features/transition/transition.spec.js b/test/unit/features/transition/transition.spec.js
index 2ecf80b854d..888fb28f4b3 100644
--- a/test/unit/features/transition/transition.spec.js
+++ b/test/unit/features/transition/transition.spec.js
@@ -769,6 +769,30 @@ if (!isIE9) {
       }).then(done)
     })
 
+    it('appear: false', done => {
+      let next
+      const vm = new Vue({
+        template: `
+          <div>
+            <transition name="test" :appear="false" @appear="appear" >
+              <div v-if="ok" class="test">foo</div>
+            </transition>
+          </div>
+        `,
+        data: { ok: true },
+        methods: {
+          appear: (el, cb) => {
+            next = cb
+          }
+        }
+      }).$mount(el)
+
+      waitForUpdate(() => {
+        expect(vm.$el.children[0].className).toBe('test')
+        expect(next).toBeUndefined()
+      }).then(done)
+    })
+
     it('transition on SVG elements', done => {
       const vm = new Vue({
         template: `

From e95fd3195e902ba03f52c86222b3a15e0abfcf66 Mon Sep 17 00:00:00 2001
From: "Filipe T. Amaral" <filipetamaral@gmail.com>
Date: Fri, 25 Jan 2019 09:51:50 -0200
Subject: [PATCH 2/2] fix(transition): Improve active attributes filter
 implementation

---
 src/platforms/web/runtime/components/transition.js | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/platforms/web/runtime/components/transition.js b/src/platforms/web/runtime/components/transition.js
index 0901fc304d7..171ea28ca32 100644
--- a/src/platforms/web/runtime/components/transition.js
+++ b/src/platforms/web/runtime/components/transition.js
@@ -40,13 +40,9 @@ function getRealChild (vnode: ?VNode): ?VNode {
   }
 }
 
-function isAttrDisabled (k: string): boolean {
-  var data: Object = this;
-  const attr = data[camelize(k)]
-  return typeof attr == "undefined" ||
-         typeof attr !== "undefined" &&
-         (typeof attr === "boolean" && attr ||
-          typeof attr === "string" && attr == "false")
+function activeAttr (k: string): boolean {
+  // assuming active if undefined
+  return this[camelize(k)] === undefined || this[camelize(k)] === true
 }
 
 export function extractTransitionData (comp: Component): Object {
@@ -60,7 +56,7 @@ export function extractTransitionData (comp: Component): Object {
   // extract listeners and pass them directly to the transition methods
   const listeners: Object = options._parentListeners || {}
   // remove the listeners that are explicitily disabled
-  const listenerKeys: Array<string> = Object.keys(listeners).filter(isAttrDisabled, data)
+  const listenerKeys: Array<string> = Object.keys(listeners).filter(activeAttr, data)
   for (let i = 0; i < listenerKeys.length; i++) {
     data[camelize(listenerKeys[i])] = listeners[listenerKeys[i]]
   }