fix(reactivity): fix shallow/readonly edge cases

packages/reactivity/__tests__/readonly.spec.ts

@@ -480,21 +480,27 @@ describe('reactivity/readonly', () => {
     const r = ref(false)
     const ror = readonly(r)
     const obj = reactive({ ror })
-    try {
+    expect(() => {
       obj.ror = true
-    } catch (e) {}
-
+    }).toThrow()
     expect(obj.ror).toBe(false)
   })
+
   test('replacing a readonly ref nested in a reactive object with a new ref', () => {
     const r = ref(false)
     const ror = readonly(r)
     const obj = reactive({ ror })
-    try {
-      obj.ror = ref(true) as unknown as boolean
-    } catch (e) {}
-
+    obj.ror = ref(true) as unknown as boolean
     expect(obj.ror).toBe(true)
     expect(toRaw(obj).ror).not.toBe(ror) // ref successfully replaced
   })
+
+  test('setting readonly object to writable nested ref', () => {
+    const r = ref<any>()
+    const obj = reactive({ r })
+    const ro = readonly({})
+    obj.r = ro
+    expect(obj.r).toBe(ro)
+    expect(r.value).toBe(ro)
+  })
 })

packages/reactivity/__tests__/ref.spec.ts

@@ -10,7 +10,7 @@ import {
 } from '../src/index'
 import { computed } from '@vue/runtime-dom'
 import { shallowRef, unref, customRef, triggerRef } from '../src/ref'
-import { isShallow } from '../src/reactive'
+import { isShallow, readonly, shallowReactive } from '../src/reactive'
 
 describe('reactivity/ref', () => {
   it('should hold a value', () => {
@@ -400,4 +400,22 @@ describe('reactivity/ref', () => {
     b.value = obj
     expect(spy2).toBeCalledTimes(1)
   })
+
+  test('ref should preserve value shallow/readonly-ness', () => {
+    const original = {}
+    const r = reactive(original)
+    const s = shallowReactive(original)
+    const rr = readonly(original)
+    const a = ref(original)
+
+    expect(a.value).toBe(r)
+
+    a.value = s
+    expect(a.value).toBe(s)
+    expect(a.value).not.toBe(r)
+
+    a.value = rr
+    expect(a.value).toBe(rr)
+    expect(a.value).not.toBe(r)
+  })
 })

packages/reactivity/__tests__/shallowReactive.spec.ts

@@ -7,6 +7,7 @@ import {
 } from '../src/reactive'
 
 import { effect } from '../src/effect'
+import { Ref, isRef, ref } from '../src/ref'
 
 describe('shallowReactive', () => {
   test('should not make non-reactive properties reactive', () => {
@@ -46,6 +47,27 @@ describe('shallowReactive', () => {
     expect(isReactive(r.foo.bar)).toBe(false)
   })
 
+  // vuejs/vue#12597
+  test('should not unwrap refs', () => {
+    const foo = shallowReactive({
+      bar: ref(123)
+    })
+    expect(isRef(foo.bar)).toBe(true)
+    expect(foo.bar.value).toBe(123)
+  })
+
+  // vuejs/vue#12688
+  test('should not mutate refs', () => {
+    const original = ref(123)
+    const foo = shallowReactive<{ bar: Ref<number> | number }>({
+      bar: original
+    })
+    expect(foo.bar).toBe(original)
+    foo.bar = 234
+    expect(foo.bar).toBe(234)
+    expect(original.value).toBe(123)
+  })
+
   test('should respect shallow/deep versions of same target on access', () => {
     const original = {}
     const shallow = shallowReactive(original)