fix: shallowReadonly should keep reactive properties reactive

ref #552

packages/reactivity/__tests__/readonly.spec.ts

@@ -470,5 +470,13 @@ describe('reactivity/readonly', () => {
         `Set operation on key "foo" failed: target is readonly.`
       ).not.toHaveBeenWarned()
     })
+
+    test('should keep reactive properties reactive', () => {
+      const props: any = shallowReadonly({ n: reactive({ foo: 1 }) })
+      unlock()
+      props.n = reactive({ foo: 2 })
+      lock()
+      expect(isReactive(props.n)).toBe(true)
+    })
   })
 })

packages/reactivity/src/baseHandlers.ts

@@ -11,7 +11,11 @@ const builtInSymbols = new Set(
     .filter(isSymbol)
 )
 
-function createGetter(isReadonly: boolean, shallow = false) {
+const get = createGetter()
+const readonlyGet = createGetter(true)
+const shallowReadonlyGet = createGetter(true, true)
+
+function createGetter(isReadonly = false, shallow = false) {
   return function get(target: object, key: string | symbol, receiver: object) {
     const res = Reflect.get(target, key, receiver)
     if (isSymbol(key) && builtInSymbols.has(key)) {
@@ -36,18 +40,38 @@ function createGetter(isReadonly: boolean, shallow = false) {
   }
 }
 
-function set(
+const set = createSetter()
+const readonlySet = createSetter(true)
+const shallowReadonlySet = createSetter(true, true)
+
+function createSetter(isReadonly = false, shallow = false) {
+  return function set(
     target: object,
     key: string | symbol,
     value: unknown,
     receiver: object
   ): boolean {
-  value = toRaw(value)
+    if (isReadonly && LOCKED) {
+      if (__DEV__) {
+        console.warn(
+          `Set operation on key "${String(key)}" failed: target is readonly.`,
+          target
+        )
+      }
+      return true
+    }
+
     const oldValue = (target as any)[key]
+    if (!shallow) {
+      value = toRaw(value)
       if (isRef(oldValue) && !isRef(value)) {
         oldValue.value = value
         return true
       }
+    } else {
+      // in shallow mode, objects are set as-is regardless of reactive or not
+    }
+
     const hadKey = hasOwn(target, key)
     const result = Reflect.set(target, key, value, receiver)
     // don't trigger if target is something up in the prototype chain of original
@@ -70,6 +94,7 @@ function set(
     }
     return result
   }
+}
 
 function deleteProperty(target: object, key: string | symbol): boolean {
   const hadKey = hasOwn(target, key)
@@ -98,7 +123,7 @@ function ownKeys(target: object): (string | number | symbol)[] {
 }
 
 export const mutableHandlers: ProxyHandler<object> = {
-  get: createGetter(false),
+  get,
   set,
   deleteProperty,
   has,
@@ -106,27 +131,10 @@ export const mutableHandlers: ProxyHandler<object> = {
 }
 
 export const readonlyHandlers: ProxyHandler<object> = {
-  get: createGetter(true),
+  get: readonlyGet,
-
+  set: readonlySet,
-  set(
+  has,
-    target: object,
+  ownKeys,
-    key: string | symbol,
-    value: unknown,
-    receiver: object
-  ): boolean {
-    if (LOCKED) {
-      if (__DEV__) {
-        console.warn(
-          `Set operation on key "${String(key)}" failed: target is readonly.`,
-          target
-        )
-      }
-      return true
-    } else {
-      return set(target, key, value, receiver)
-    }
-  },
-
   deleteProperty(target: object, key: string | symbol): boolean {
     if (LOCKED) {
       if (__DEV__) {
@@ -141,10 +149,7 @@ export const readonlyHandlers: ProxyHandler<object> = {
     } else {
       return deleteProperty(target, key)
     }
-  },
+  }
-
-  has,
-  ownKeys
 }
 
 // props handlers are special in the sense that it should not unwrap top-level
@@ -152,5 +157,6 @@ export const readonlyHandlers: ProxyHandler<object> = {
 // retain the reactivity of the normal readonly object.
 export const shallowReadonlyHandlers: ProxyHandler<object> = {
   ...readonlyHandlers,
-  get: createGetter(true, true)
+  get: shallowReadonlyGet,
+  set: shallowReadonlySet
 }