Revert "feat: auto cache inline prop literals to avoid child re-render"

This reverts commit 996eb00a0a.

flow/component.js

@@ -69,7 +69,6 @@ declare interface Component {
   _staticTrees: ?Array<VNode>; // v-once cached trees
   _hasHookEvent: boolean;
   _provided: ?Object;
-  _inlineComputed: ?{ [key: string]: Watcher }; // inline computed watchers for literal props
   // _virtualComponents?: { [key: string]: Component };
 
   // private methods
@@ -131,8 +130,6 @@ declare interface Component {
   _k: (eventKeyCode: number, key: string, builtInAlias?: number | Array<number>, eventKeyName?: string) => ?boolean;
   // resolve scoped slots
   _u: (scopedSlots: ScopedSlotsData, res?: Object) => { [key: string]: Function };
-  // create / return value from inline computed
-  _a: (id: number, getter: Function) => any;
 
   // SSR specific
   _ssrNode: Function;

src/compiler/parser/index.js

@@ -29,20 +29,16 @@ const argRE = /:(.*)$/
 export const bindRE = /^:|^v-bind:/
 const modifierRE = /\.[^.]+/g
 
-const literalValueRE = /^(\{.*\}|\[.*\])$/
-
 const decodeHTMLCached = cached(he.decode)
 
 // configurable state
 export let warn: any
-let literalPropId
 let delimiters
 let transforms
 let preTransforms
 let postTransforms
 let platformIsPreTag
 let platformMustUseProp
-let platformIsReservedTag
 let platformGetTagNamespace
 
 type Attr = { name: string; value: string };
@@ -70,11 +66,9 @@ export function parse (
   options: CompilerOptions
 ): ASTElement | void {
   warn = options.warn || baseWarn
-  literalPropId = 0
 
   platformIsPreTag = options.isPreTag || no
   platformMustUseProp = options.mustUseProp || no
-  platformIsReservedTag = options.isReservedTag || no
   platformGetTagNamespace = options.getTagNamespace || no
 
   transforms = pluckModuleFunction(options.modules, 'transformNode')
@@ -544,15 +538,6 @@ function processAttrs (el) {
             )
           }
         }
-        // optimize literal values in component props by wrapping them
-        // in an inline watcher to avoid unnecessary re-renders
-        if (
-          !platformIsReservedTag(el.tag) &&
-          el.tag !== 'slot' &&
-          literalValueRE.test(value.trim())
-        ) {
-          value = `_a(${literalPropId++},function(){return ${value}})`
-        }
         if (isProp || (
           !el.component && platformMustUseProp(el.tag, el.attrsMap.type, name)
         )) {

src/core/instance/render-helpers/create-inline-computed.js

@@ -1,28 +0,0 @@
-/* @flow */
-
-import { noop } from 'shared/util'
-import Watcher from 'core/observer/watcher'
-
-/**
- * This runtime helper creates an inline computed property for component
- * props that contain object or array literals. The caching ensures the same
- * object/array is returned unless the value has indeed changed, thus avoiding
- * the child component to always re-render when comparing props values.
- *
- * Installed to the instance as _a, requires special handling in parser that
- * transforms the following
- *   <foo :bar="{ a: 1 }"/>
- * to:
- *   <foo :bar="_a(0, function(){return { a: 1 }})"
- */
-export function createInlineComputed (id: string, getter: Function): any {
-  const vm: Component = this
-  const watchers = vm._inlineComputed || (vm._inlineComputed = {})
-  const cached = watchers[id]
-  if (cached) {
-    return cached.value
-  } else {
-    watchers[id] = new Watcher(vm, getter, noop, { sync: true })
-    return watchers[id].value
-  }
-}

src/core/instance/render-helpers/index.js

@@ -10,7 +10,6 @@ import { bindObjectProps } from './bind-object-props'
 import { renderStatic, markOnce } from './render-static'
 import { bindObjectListeners } from './bind-object-listeners'
 import { resolveScopedSlots } from './resolve-slots'
-import { createInlineComputed } from './create-inline-computed'
 
 export function installRenderHelpers (target: any) {
   target._o = markOnce
@@ -28,5 +27,4 @@ export function installRenderHelpers (target: any) {
   target._e = createEmptyVNode
   target._u = resolveScopedSlots
   target._g = bindObjectListeners
-  target._a = createInlineComputed
 }

src/core/instance/state.js

@@ -47,7 +47,6 @@ export function proxy (target: Object, sourceKey: string, key: string) {
 
 export function initState (vm: Component) {
   vm._watchers = []
-  vm._inlineComputed = null
   const opts = vm.$options
   if (opts.props) initProps(vm, opts.props)
   if (opts.methods) initMethods(vm, opts.methods)

test/unit/features/options/props.spec.js

@@ -512,38 +512,4 @@ describe('Options props', () => {
       expect(`"${attr}" is a reserved attribute`).toHaveBeenWarned()
     })
   })
-
-  it('should not trigger re-render on non-changed inline literals', done => {
-    const updated = jasmine.createSpy('updated')
-    const vm = new Vue({
-      data: {
-        n: 1,
-        m: 1
-      },
-      template: `
-        <div id="app">
-          {{ n }} {{ m }} <foo :a="{ n: 1 }" :b="{ n: n }"/>
-        </div>
-      `,
-      components: {
-        foo: {
-          props: ['a', 'b'],
-          updated,
-          template: `<div>{{ a.n }} {{ b.n }}</div>`
-        }
-      }
-    }).$mount()
-
-    expect(vm.$el.textContent).toContain('1 1 1 1')
-    vm.n++ // literals that actually contain changed reactive data should trigger update
-    waitForUpdate(() => {
-      expect(vm.$el.textContent).toContain('2 1 1 2')
-      expect(updated.calls.count()).toBe(1)
-    }).then(() => {
-      vm.m++ // changing data that does not affect any literals should not trigger update
-    }).then(() => {
-      expect(vm.$el.textContent).toContain('2 2 1 2')
-      expect(updated.calls.count()).toBe(1)
-    }).then(done)
-  })
 })