fix(patch.js): fix functional component scope attribute update

fix functional component update scope attribute when patch use same node

fix vuejs#11171

src/core/vdom/patch.js

@@ -547,6 +547,9 @@ export function createPatchFunction (backend) {
 
     const oldCh = oldVnode.children
     const ch = vnode.children
+    if (isDef(vnode.fnScopeId)) {
+      setScope(vnode)
+    }
     if (isDef(data) && isPatchable(vnode)) {
       for (i = 0; i < cbs.update.length; ++i) cbs.update[i](oldVnode, vnode)
       if (isDef(i = data.hook) && isDef(i = i.update)) i(oldVnode, vnode)

test/unit/modules/vdom/patch/edge-cases.spec.js

@@ -1,4 +1,5 @@
 import Vue from 'vue'
+import { patch } from 'web/runtime/patch'
 
 describe('vdom patch: edge cases', () => {
   // exposed by #3406
@@ -432,4 +433,25 @@ describe('vdom patch: edge cases', () => {
       expect(vm.$el.textContent).not.toMatch('Infinity')
     }).then(done)
   })
+
+  // #11171
+  it("should replace functional element scope attribute", () => {
+    const vm = new Vue({
+      components: {
+        foo: {
+          functional: true,
+          _scopeId: "foo",
+          render (h) {
+            return h('div')
+          }
+        }
+      }
+    })
+    const h = vm.$createElement
+    const vnode = h('foo')
+    const oldVnode = h("div")
+    patch(null, oldVnode)
+    let elm = patch(oldVnode, vnode)
+    expect(elm.hasAttribute("foo")).toBe(true)
+  })
 })