fix(runtime-vapor): should not warn invalid watch source when directly watching props (#13384)

packages/runtime-vapor/__tests__/componentProps.spec.ts

@@ -497,6 +497,36 @@ describe('component: props', () => {
     expect(changeSpy).toHaveBeenCalledTimes(1)
   })
 
+  test('should not warn invalid watch source when directly watching props', async () => {
+    const changeSpy = vi.fn()
+    const { render, html } = define({
+      props: {
+        foo: {
+          type: String,
+        },
+      },
+      setup(props: any) {
+        watch(props, changeSpy)
+        const t0 = template('<h1></h1>')
+        const n0 = t0()
+        renderEffect(() => {
+          setElementText(n0, String(props.foo))
+        })
+        return n0
+      },
+    })
+
+    const foo = ref('foo')
+    render({ foo: () => foo.value })
+    expect(html()).toBe(`<h1>foo</h1>`)
+    expect('Invalid watch source').not.toHaveBeenWarned()
+
+    foo.value = 'bar'
+    await nextTick()
+    expect(html()).toBe(`<h1>bar</h1>`)
+    expect(changeSpy).toHaveBeenCalledTimes(1)
+  })
+
   test('support null in required + multiple-type declarations', () => {
     const { render } = define({
       props: {

packages/runtime-vapor/src/componentProps.ts

@@ -21,6 +21,7 @@ import {
   validateProps,
   warn,
 } from '@vue/runtime-dom'
+import { ReactiveFlags } from '@vue/reactivity'
 import { normalizeEmitsOptions } from './componentEmits'
 import { renderEffect } from './renderEffect'
 
@@ -63,6 +64,9 @@ export function getPropsProxyHandlers(
     : YES
 
   const getProp = (instance: VaporComponentInstance, key: string | symbol) => {
+    // this enables direct watching of props and prevents `Invalid watch source` DEV warnings.
+    if (key === ReactiveFlags.IS_REACTIVE) return true
+
     if (!isProp(key)) return
     const rawProps = instance.rawProps
     const dynamicSources = rawProps.$