fix(reactivity): avoid duplication proxy

[lijingfaatcumt]

in vue3, designing reactiveMap and readonlyMap is for cache the proxy version if the target has the proxy or the target is a proxy, but in you pr, the code below will cause the cache useless

let proxy = reactive(origin)
let shallowProxy = shallowProxy(origin)

let proxyCopy = reactive(shallowProxy)
proxyCopy === proxy // false

in code above, i want to make proxyCopy === proxy returns true
in order to solve the problem,the createReactiveObject function may modify follow below

function createReactiveObject(
  target: Target,
  isReadonly: boolean,
  shallow: boolean,
  baseHandlers: ProxyHandler<any>,
  collectionHandlers: ProxyHandler<any>
) {
  if (!isObject(target)) {
    if (__DEV__) {
      console.warn(`value cannot be made reactive: ${String(target)}`)
    }
    return target
  }
  const proxyMap = getProxyMap(isReadonly, shallow)
  // target already has corresponding Proxy
  const existingProxy = proxyMap.get(target)
  if (existingProxy) {
    return existingProxy
  }
  // target is already a Proxy, return it.
  // exception: calling readonly() on a reactive object
  if (target[ReactiveFlags.RAW]) {
    if (
      target[ReactiveFlags.IS_READONLY] === isReadonly &&
      target[ReactiveFlags.IS_SHALLOW] === shallow
    ) {
      return target
    }
    if (!isReadonly || !target[ReactiveFlags.IS_REACTIVE]) {
      target = toRaw(target)
      const existingProxy = proxyMap.get(target)
      if (existingProxy) {
        return existingProxy
      }
    }
  }
  // only a whitelist of value types can be observed.
  const targetType = getTargetType(target)
  if (targetType === TargetType.INVALID) {
    return target
  }
  const proxy = new Proxy(
    target,
    targetType === TargetType.COLLECTION ? collectionHandlers : baseHandlers
  )
  proxyMap.set(target, proxy)
  return proxy
}

[posva]

As said in the other PR, please provide a reproduction or failing test when reporting or fixing a bug Nevermind, the colors on github branch names confused me 🙃

[LinusBorg]

You have a point here, but I don't think the solution is the best one.

Checking the WeakMap for an existing entry is a comparatively expensive OP, which is why it's been placed after the check of ReactiveFlags.RAW etc.

Will look further into it later.

[lijingfaatcumt]

You have a point here, but I don't think the solution is the best one.

Checking the WeakMap for an existing entry is a comparatively expensive OP, which is why it's been placed after the check of ReactiveFlags.RAW etc.

Will look further into it later.

@LinusBorg i push the pr again, modify the solution of avoiding duplication proxy by 'isReadonly' and 'isShallow' property