fix(reactivity): fix shallow readonly behavior for collections (#3003)

fix #3007

packages/reactivity/src/collectionHandlers.ts

@@ -44,7 +44,7 @@ function get(
   }
   !isReadonly && track(rawTarget, TrackOpTypes.GET, rawKey)
   const { has } = getProto(rawTarget)
-  const wrap = isReadonly ? toReadonly : isShallow ? toShallow : toReactive
+  const wrap = isShallow ? toShallow : isReadonly ? toReadonly : toReactive
   if (has.call(rawTarget, key)) {
     return wrap(target.get(key))
   } else if (has.call(rawTarget, rawKey)) {
@@ -151,7 +151,7 @@ function createForEach(isReadonly: boolean, isShallow: boolean) {
     const observed = this as any
     const target = observed[ReactiveFlags.RAW]
     const rawTarget = toRaw(target)
-    const wrap = isReadonly ? toReadonly : isShallow ? toShallow : toReactive
+    const wrap = isShallow ? toShallow : isReadonly ? toReadonly : toReactive
     !isReadonly && track(rawTarget, TrackOpTypes.ITERATE, ITERATE_KEY)
     return target.forEach((value: unknown, key: unknown) => {
       // important: make sure the callback is
@@ -191,7 +191,7 @@ function createIterableMethod(
       method === 'entries' || (method === Symbol.iterator && targetIsMap)
     const isKeyOnly = method === 'keys' && targetIsMap
     const innerIterator = target[method](...args)
-    const wrap = isReadonly ? toReadonly : isShallow ? toShallow : toReactive
+    const wrap = isShallow ? toShallow : isReadonly ? toReadonly : toReactive
     !isReadonly &&
       track(
         rawTarget,
@@ -279,6 +279,23 @@ const readonlyInstrumentations: Record<string, Function> = {
   forEach: createForEach(true, false)
 }
 
+const shallowReadonlyInstrumentations: Record<string, Function> = {
+  get(this: MapTypes, key: unknown) {
+    return get(this, key, true, true)
+  },
+  get size() {
+    return size((this as unknown) as IterableCollections, true)
+  },
+  has(this: MapTypes, key: unknown) {
+    return has.call(this, key, true)
+  },
+  add: createReadonlyMethod(TriggerOpTypes.ADD),
+  set: createReadonlyMethod(TriggerOpTypes.SET),
+  delete: createReadonlyMethod(TriggerOpTypes.DELETE),
+  clear: createReadonlyMethod(TriggerOpTypes.CLEAR),
+  forEach: createForEach(true, true)
+}
+
 const iteratorMethods = ['keys', 'values', 'entries', Symbol.iterator]
 iteratorMethods.forEach(method => {
   mutableInstrumentations[method as string] = createIterableMethod(
@@ -296,11 +313,18 @@ iteratorMethods.forEach(method => {
     false,
     true
   )
+  shallowReadonlyInstrumentations[method as string] = createIterableMethod(
+    method,
+    true,
+    true
+  )
 })
 
 function createInstrumentationGetter(isReadonly: boolean, shallow: boolean) {
   const instrumentations = shallow
-    ? shallowInstrumentations
+    ? isReadonly
+      ? shallowReadonlyInstrumentations
+      : shallowInstrumentations
     : isReadonly
       ? readonlyInstrumentations
       : mutableInstrumentations
@@ -340,6 +364,12 @@ export const readonlyCollectionHandlers: ProxyHandler<CollectionTypes> = {
   get: createInstrumentationGetter(true, false)
 }
 
+export const shallowReadonlyCollectionHandlers: ProxyHandler<
+  CollectionTypes
+> = {
+  get: createInstrumentationGetter(true, true)
+}
+
 function checkIdentityKeys(
   target: CollectionTypes,
   has: (key: unknown) => boolean,

packages/reactivity/src/reactive.ts

@@ -8,7 +8,8 @@ import {
 import {
   mutableCollectionHandlers,
   readonlyCollectionHandlers,
-  shallowCollectionHandlers
+  shallowCollectionHandlers,
+  shallowReadonlyCollectionHandlers
 } from './collectionHandlers'
 import { UnwrapRef, Ref } from './ref'
 
@@ -159,7 +160,7 @@ export function shallowReadonly<T extends object>(
     target,
     true,
     shallowReadonlyHandlers,
-    readonlyCollectionHandlers
+    shallowReadonlyCollectionHandlers
   )
 }