unbind v-show if no longer present during patch (fix #4484)

src/core/vdom/modules/directives.js

@@ -20,6 +20,7 @@ function updateDirectives (oldVnode: VNodeWithData, vnode: VNodeWithData) {
 
 function _update (oldVnode, vnode) {
   const isCreate = oldVnode === emptyNode
+  const isDestroy = vnode === emptyNode
   const oldDirs = normalizeDirectives(oldVnode.data.directives, oldVnode.context)
   const newDirs = normalizeDirectives(vnode.data.directives, vnode.context)
 
@@ -71,7 +72,7 @@ function _update (oldVnode, vnode) {
     for (key in oldDirs) {
       if (!newDirs[key]) {
         // no longer present, unbind
-        callHook(oldDirs[key], 'unbind', oldVnode)
+        callHook(oldDirs[key], 'unbind', oldVnode, oldVnode, isDestroy)
       }
     }
   }
@@ -103,9 +104,9 @@ function getRawDirName (dir: VNodeDirective): string {
   return dir.rawName || `${dir.name}.${Object.keys(dir.modifiers || {}).join('.')}`
 }
 
-function callHook (dir, hook, vnode, oldVnode) {
+function callHook (dir, hook, vnode, oldVnode, isDestroy) {
   const fn = dir.def && dir.def[hook]
   if (fn) {
-    fn(vnode.elm, dir, vnode, oldVnode)
+    fn(vnode.elm, dir, vnode, oldVnode, isDestroy)
   }
 }

src/platforms/web/runtime/directives/show.js

@@ -25,6 +25,7 @@ export default {
       el.style.display = value ? originalDisplay : 'none'
     }
   },
+
   update (el: any, { value, oldValue }: VNodeDirective, vnode: VNodeWithData) {
     /* istanbul ignore if */
     if (value === oldValue) return
@@ -44,5 +45,17 @@ export default {
     } else {
       el.style.display = value ? el.__vOriginalDisplay : 'none'
     }
+  },
+
+  unbind (
+    el: any,
+    binding: VNodeDirective,
+    vnode: VNodeWithData,
+    oldVnode: VNodeWithData,
+    isDestroy: boolean
+  ) {
+    if (!isDestroy) {
+      el.style.display = el.__vOriginalDisplay
+    }
   }
 }

test/unit/features/directives/show.spec.js

@@ -64,4 +64,21 @@ describe('Directive v-show', () => {
       expect(vm.$el.firstChild.style.display).toBe('block')
     }).then(done)
   })
+
+  it('should support unbind when reused', done => {
+    const vm = new Vue({
+      template:
+        '<div v-if="tester"><span v-show="false"></span></div>' +
+        '<div v-else><span @click="tester=!tester">show</span></div>',
+      data: { tester: true }
+    }).$mount()
+    expect(vm.$el.firstChild.style.display).toBe('none')
+    vm.tester = false
+    waitForUpdate(() => {
+      expect(vm.$el.firstChild.style.display).toBe('')
+      vm.tester = true
+    }).then(() => {
+      expect(vm.$el.firstChild.style.display).toBe('none')
+    }).then(done)
+  })
 })