From 9c304bfe7942a20264235865b4bb5f6e53fdee0d Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Tue, 18 Jan 2022 09:22:03 +0800
Subject: [PATCH] fix(reactivity): differentiate shallow/deep proxies of same
 target when nested in reactive

fix #5271
---
 .../__tests__/shallowReactive.spec.ts         | 20 +++++++++++++++++++
 packages/reactivity/src/baseHandlers.ts       |  9 ++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/packages/reactivity/__tests__/shallowReactive.spec.ts b/packages/reactivity/__tests__/shallowReactive.spec.ts
index f7c7e07b055..200aa462496 100644
--- a/packages/reactivity/__tests__/shallowReactive.spec.ts
+++ b/packages/reactivity/__tests__/shallowReactive.spec.ts
@@ -35,6 +35,26 @@ describe('shallowReactive', () => {
     expect(isShallow(shallowReadonly({}))).toBe(true)
   })
 
+  // #5271
+  test('should respect shallow reactive nested inside reactive on reset', () => {
+    const r = reactive({ foo: shallowReactive({ bar: {} }) })
+    expect(isShallow(r.foo)).toBe(true)
+    expect(isReactive(r.foo.bar)).toBe(false)
+
+    r.foo = shallowReactive({ bar: {} })
+    expect(isShallow(r.foo)).toBe(true)
+    expect(isReactive(r.foo.bar)).toBe(false)
+  })
+
+  test('should respect shallow/deep versions of same target on access', () => {
+    const original = {}
+    const shallow = shallowReactive(original)
+    const deep = reactive(original)
+    const r = reactive({ shallow, deep })
+    expect(r.shallow).toBe(shallow)
+    expect(r.deep).toBe(deep)
+  })
+
   describe('collections', () => {
     test('should be reactive', () => {
       const shallowSet = shallowReactive(new Set())
diff --git a/packages/reactivity/src/baseHandlers.ts b/packages/reactivity/src/baseHandlers.ts
index 3d2ba661973..97acf063f67 100644
--- a/packages/reactivity/src/baseHandlers.ts
+++ b/packages/reactivity/src/baseHandlers.ts
@@ -8,7 +8,8 @@ import {
   reactiveMap,
   shallowReactiveMap,
   shallowReadonlyMap,
-  isReadonly
+  isReadonly,
+  isShallow
 } from './reactive'
 import { TrackOpTypes, TriggerOpTypes } from './operations'
 import {
@@ -150,8 +151,10 @@ function createSetter(shallow = false) {
   ): boolean {
     let oldValue = (target as any)[key]
     if (!shallow && !isReadonly(value)) {
-      value = toRaw(value)
-      oldValue = toRaw(oldValue)
+      if (!isShallow(value)) {
+        value = toRaw(value)
+        oldValue = toRaw(oldValue)
+      }
       if (!isArray(target) && isRef(oldValue) && !isRef(value)) {
         oldValue.value = value
         return true