fix(shallowReadonly) : shallowReadonly should work for ref. (#704)

Author: ygj6

src/reactivity/readonly.ts

@@ -1,6 +1,7 @@
 import { reactive, Ref, UnwrapRef } from '.'
 import { isArray, isPlainObject, warn } from '../utils'
 import { readonlySet } from '../utils/sets'
+import { isRef } from './ref'
 
 export function isReadonly(obj: any): boolean {
   return readonlySet.has(obj)
@@ -47,7 +48,10 @@ export function readonly<T extends object>(
 
 export function shallowReadonly<T extends object>(obj: T): Readonly<T>
 export function shallowReadonly(obj: any): any {
-  if (!(isPlainObject(obj) || isArray(obj)) || !Object.isExtensible(obj)) {
+  if (
+    !(isPlainObject(obj) || isArray(obj)) ||
+    (!Object.isExtensible(obj) && !isRef(obj))
+  ) {
     return obj
   }
 
@@ -60,7 +64,7 @@ export function shallowReadonly(obj: any): any {
     let val = obj[key]
     let getter: (() => any) | undefined
     const property = Object.getOwnPropertyDescriptor(obj, key)
-    if (property) {
+    if (property && !isRef(obj)) {
       if (property.configurable === false) {
         continue
       }

test/v3/reactivity/readonly.spec.ts

@@ -1,5 +1,7 @@
 import { mockWarn } from '../../helpers/mockWarn'
-import { shallowReadonly, isReactive } from '../../../src'
+import { shallowReadonly, isReactive, ref, reactive } from '../../../src'
+
+const Vue = require('vue/dist/vue.common.js')
 
 // /**
 //  * @see https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-4.html
@@ -372,5 +374,32 @@ describe('reactivity/readonly', () => {
         `Set operation on key "foo" failed: target is readonly.`
       ).not.toHaveBeenWarned()
     })
+
+    // #669
+    test('shallowReadonly should work for refs', () => {
+      const vm = new Vue({
+        template: '<div>{{ count }} {{ countRef }}</div>',
+        setup() {
+          const count = reactive({ number: 0 })
+          const countRef = ref(0)
+
+          const countReadonly = shallowReadonly(count)
+          const countRefReadonly = shallowReadonly(countRef)
+
+          setTimeout(() => {
+            // @ts-expect-error
+            countReadonly.number++
+            // @ts-expect-error
+            countRefReadonly.value++
+          }, 2000)
+          return {
+            count,
+            countRef,
+          }
+        },
+      }).$mount()
+
+      expect(vm.$el.textContent).toBe(`{\n  "number": 0\n} 0`)
+    })
   })
 })