ensure v-model to have higher priority than v-on events (fix #3468)

Author: yyx990803

src/compiler/helpers.js

@@ -46,7 +46,8 @@ export function addHandler (
   el: ASTElement,
   name: string,
   value: string,
-  modifiers: ?{ [key: string]: true }
+  modifiers: ?{ [key: string]: true },
+  important: ?boolean
 ) {
   // check capture modifier
   if (modifiers && modifiers.capture) {
@@ -64,9 +65,9 @@ export function addHandler (
   const handlers = events[name]
   /* istanbul ignore if */
   if (Array.isArray(handlers)) {
-    handlers.push(newHandler)
+    important ? handlers.unshift(newHandler) : handlers.push(newHandler)
   } else if (handlers) {
-    events[name] = [handlers, newHandler]
+    events[name] = important ? [newHandler, handlers] : [handlers, newHandler]
   } else {
     events[name] = newHandler
   }

src/platforms/web/compiler/directives/model.js

@@ -55,7 +55,8 @@ function genCheckboxModel (el: ASTElement, value: ?string) {
           '$$i=$$a.indexOf($$v);' +
       `if($$c){$$i<0&&(${value}=$$a.concat($$v))}` +
       `else{$$i>-1&&(${value}=$$a.slice(0,$$i).concat($$a.slice($$i+1)))}` +
-    `}else{${value}=$$c}`
+    `}else{${value}=$$c}`,
+    null, true
   )
 }
 
@@ -70,7 +71,7 @@ function genRadioModel (el: ASTElement, value: ?string) {
   }
   const valueBinding = getBindingAttr(el, 'value')
   addProp(el, 'checked', `(${value})===(${valueBinding})`)
-  addHandler(el, 'change', `${value}=${valueBinding}`)
+  addHandler(el, 'change', `${value}=${valueBinding}`, null, true)
 }
 
 function genDefaultModel (
@@ -111,7 +112,7 @@ function genDefaultModel (
     code = `if($event.target.composing)return;${code}`
   }
   addProp(el, 'value', isNative ? `_s(${value})` : `(${value})`)
-  addHandler(el, event, code)
+  addHandler(el, event, code, null, true)
   if (needCompositionGuard) {
     // need runtime directive code to help with composition events
     return true
@@ -126,7 +127,7 @@ function genSelect (el: ASTElement, value: ?string) {
     `.call($event.target.options,function(o){return o.selected})` +
     `.map(function(o){return "_value" in o ? o._value : o.value})` +
     (el.attrsMap.multiple == null ? '[0]' : '')
-  addHandler(el, 'change', code)
+  addHandler(el, 'change', code, null, true)
   // need runtime to help with possible dynamically generated options
   return true
 }

test/unit/features/directives/model-text.spec.js

@@ -141,4 +141,23 @@ describe('Directive v-model text', () => {
     }).$mount()
     expect('v-model is not supported on element type: <div>').toHaveBeenWarned()
   })
+
+  // #3468
+  it('should have higher priority than user v-on events', () => {
+    const spy = jasmine.createSpy()
+    const vm = new Vue({
+      data: {
+        a: 'a'
+      },
+      template: '<input v-model="a" @input="onInput">',
+      methods: {
+        onInput (e) {
+          spy(e.target.value)
+        }
+      }
+    }).$mount()
+    vm.$el.value = 'b'
+    triggerEvent(vm.$el, 'input')
+    expect(spy).toHaveBeenCalledWith('b')
+  })
 })