fix: ensure functionalContext is cloned during slot clones

fix #7106

src/core/instance/render-helpers/resolve-slots.js

@@ -20,7 +20,7 @@ export function resolveSlots (
     }
     // named slots should only be respected if the vnode was rendered in the
     // same context.
-    if ((child.context === context || child.functionalContext === context) &&
+    if ((child.context === context || child.fnContext === context) &&
       data && data.slot != null
     ) {
       const name = child.data.slot

src/core/vdom/create-functional-component.js

@@ -49,8 +49,8 @@ function FunctionalRenderContext (
     this._c = (a, b, c, d) => {
       const vnode: ?VNode = createElement(contextVm, a, b, c, d, needNormalization)
       if (vnode) {
-        vnode.functionalScopeId = options._scopeId
-        vnode.functionalContext = parent
+        vnode.fnScopeId = options._scopeId
+        vnode.fnContext = parent
       }
       return vnode
     }
@@ -91,8 +91,8 @@ export function createFunctionalComponent (
   const vnode = options.render.call(null, renderContext._c, renderContext)
 
   if (vnode instanceof VNode) {
-    vnode.functionalContext = contextVm
-    vnode.functionalOptions = options
+    vnode.fnContext = contextVm
+    vnode.fnOptions = options
     if (data.slot) {
       (vnode.data || (vnode.data = {})).slot = data.slot
     }

src/core/vdom/patch.js

@@ -294,7 +294,7 @@ export function createPatchFunction (backend) {
   // of going through the normal attribute patching process.
   function setScope (vnode) {
     let i
-    if (isDef(i = vnode.functionalScopeId)) {
+    if (isDef(i = vnode.fnScopeId)) {
       nodeOps.setAttribute(vnode.elm, i, '')
     } else {
       let ancestor = vnode
@@ -308,7 +308,7 @@ export function createPatchFunction (backend) {
     // for slot content they should also get the scopeId from the host instance.
     if (isDef(i = activeInstance) &&
       i !== vnode.context &&
-      i !== vnode.functionalContext &&
+      i !== vnode.fnContext &&
       isDef(i = i.$options._scopeId)
     ) {
       nodeOps.setAttribute(vnode.elm, i, '')

src/core/vdom/vnode.js

@@ -24,9 +24,9 @@ export default class VNode {
   asyncMeta: Object | void;
   isAsyncPlaceholder: boolean;
   ssrContext: Object | void;
-  functionalContext: Component | void; // real context vm for functional nodes
-  functionalOptions: ?ComponentOptions; // for SSR caching
-  functionalScopeId: ?string; // functioanl scope id support
+  fnContext: Component | void; // real context vm for functional nodes
+  fnOptions: ?ComponentOptions; // for SSR caching
+  fnScopeId: ?string; // functioanl scope id support
 
   constructor (
     tag?: string,
@@ -45,9 +45,9 @@ export default class VNode {
     this.elm = elm
     this.ns = undefined
     this.context = context
-    this.functionalContext = undefined
-    this.functionalOptions = undefined
-    this.functionalScopeId = undefined
+    this.fnContext = undefined
+    this.fnOptions = undefined
+    this.fnScopeId = undefined
     this.key = data && data.key
     this.componentOptions = componentOptions
     this.componentInstance = undefined
@@ -101,6 +101,9 @@ export function cloneVNode (vnode: VNode, deep?: boolean): VNode {
   cloned.isStatic = vnode.isStatic
   cloned.key = vnode.key
   cloned.isComment = vnode.isComment
+  cloned.fnContext = vnode.fnContext
+  cloned.fnOptions = vnode.fnOptions
+  cloned.fnScopeId = vnode.fnScopeId
   cloned.isCloned = true
   if (deep) {
     if (vnode.children) {

src/server/render.js

@@ -252,8 +252,8 @@ function renderElement (el, isRoot, context) {
     el.data.attrs[SSR_ATTR] = 'true'
   }
 
-  if (el.functionalOptions) {
-    registerComponentForCache(el.functionalOptions, write)
+  if (el.fnOptions) {
+    registerComponentForCache(el.fnOptions, write)
   }
 
   const startTag = renderStartingTag(el, context)

test/unit/features/component/component-slot.spec.js

@@ -779,4 +779,49 @@ describe('Component slot', () => {
 
     expect(vm.$el.innerHTML).toBe('<div class="foo"><div class="bar">fallback</div></div>')
   })
+
+  // #7106
+  it('should not lose functional slot across renders', done => {
+    const One = {
+      data: () => ({
+        foo: true
+      }),
+      render (h) {
+        this.foo
+        return h('div', this.$slots.slot)
+      }
+    }
+
+    const Two = {
+      render (h) {
+        return h('span', this.$slots.slot)
+      }
+    }
+
+    const Three = {
+      functional: true,
+      render: (h, { children }) => h('span', children)
+    }
+
+    const vm = new Vue({
+      template: `
+        <div>
+          <one ref="one">
+            <two slot="slot">
+              <three slot="slot">hello</three>
+            </two>
+          </one>
+        </div>
+      `,
+      components: { One, Two, Three }
+    }).$mount()
+
+    expect(vm.$el.textContent).toBe('hello')
+    // trigger re-render of <one>
+    vm.$refs.one.foo = false
+    waitForUpdate(() => {
+      // should still be there
+      expect(vm.$el.textContent).toBe('hello')
+    }).then(done)
+  })
 })