watch([], cb, { immediate: true }) // cb not runing as expected

[wsi18n]

Vue version

3.5.35

Link to minimal reproduction

Steps to reproduce

import { expect, it, vi } from 'vitest'
import { watch } from 'vue' // vue@2.7
import { watch as watch3 } from 'vue3' // "vue3": "npm:vue@^3.5.35"

it('watch([], cb, { immediate: true })', async () => {
  const cb = vi.fn()
  watch([], cb, { immediate: true })
  const cb2 = vi.fn()
  watch3([], cb2, { immediate: true })

  expect(cb2).toHaveBeenCalledTimes(1) // but get 0
  expect(cb).toHaveBeenCalledTimes(1) // but get 0
})

---

A: 为什么要 watch 空数组
A: Why watch an empty array?

Q: 封装公共函数时，可以传入不定个数的参数, 比如：
Q: When encapsulating a public function, you can pass a variable number of arguments, for example:

function foo<T extends WatchSource[]>(...args: T) {
  return function wrapper(...args: T) {
     watch(args, cb, { immediate: true })
     ....
  }
}

一般情况下传参，一切正常；但未传参时，cb不执行，不符合语义和直觉
Under normal circumstances with arguments passed, everything works fine; but when no arguments are passed, the callback doesn't execute, which goes against intuition.

What is expected?

expect(cb2).toHaveBeenCalledTimes(1)
expect(cb).toHaveBeenCalledTimes(1)

What is actually happening?

0

System Info

Any additional comments?

No response