handle v-pre on component root node (fix #2026)

Author: yyx990803

src/instance/internal/lifecycle.js

@@ -1,4 +1,4 @@
-import { replace } from '../../util/index'
+import { replace, getAttr } from '../../util/index'
 import Directive from '../../directive'
 import { compile, compileRoot, transclude } from '../../compiler/index'
 
@@ -49,6 +49,11 @@ export default function (Vue) {
     el = transclude(el, options)
     this._initElement(el)
 
+    // handle v-pre on root node (#2026)
+    if (el.nodeType === 1 && getAttr(el, 'v-pre') !== null) {
+      return
+    }
+
     // root is always compiled per-instance, because
     // container attrs and props can be different every time.
     var contextOptions = this._context && this._context.$options

test/unit/specs/directives/public/pre_spec.js

@@ -2,6 +2,10 @@ var Vue = require('../../../../../src/index')
 
 describe('v-pre', function () {
 
+  beforeEach(function () {
+    spyWarns()
+  })
+
   it('should work', function () {
     var vm = new Vue({
       el: document.createElement('div'),
@@ -12,4 +16,17 @@ describe('v-pre', function () {
     })
     expect(vm.$el.firstChild.textContent).toBe('{{a}}')
   })
+
+  it('should work on root node', function () {
+    var vm = new Vue({
+      el: document.createElement('div'),
+      template: '<div v-pre>{{a}}</div>',
+      replace: true,
+      data: {
+        a: 123
+      }
+    })
+    expect(vm.$el.textContent).toBe('{{a}}')
+    expect(getWarnCount()).toBe(0)
+  })
 })