fix: use registered Vue instance for warning

Author: antfu

src/runtimeContext.ts

@@ -9,7 +9,7 @@ import {
   UnionToIntersection,
   isFunction,
 } from './utils'
-import Vue$1 from 'vue'
+import type Vue$1 from 'vue'
 
 let vueDependency: VueConstructor | undefined = undefined
 

src/utils/utils.ts

@@ -1,4 +1,4 @@
-import Vue from 'vue'
+import { getRegisteredVueOrDefault } from '../runtimeContext'
 
 const toString = (x: any) => Object.prototype.toString.call(x)
 
@@ -99,7 +99,9 @@ export function isUndef(v: any): boolean {
 }
 
 export function warn(msg: string, vm?: Vue) {
-  Vue.util.warn(msg, vm)
+  const Vue = getRegisteredVueOrDefault()
+  if (!Vue || !Vue.util) console.warn(`[vue-composition-api] ${msg}`)
+  else Vue.util.warn(msg, vm)
 }
 
 export function logError(err: Error, vm: Vue, info: string) {

test/v3/runtime-core/apiWatch.spec.ts

@@ -8,11 +8,12 @@ import {
   shallowReactive,
   nextTick,
 } from '../../../src'
-import Vue from 'vue'
+import { getRegisteredVueOrDefault } from '../../../src/runtimeContext'
 
 // reference: https://vue-composition-api-rfc.netlify.com/api.html#watch
 
 describe('api: watch', () => {
+  const Vue = getRegisteredVueOrDefault()
   // const warnSpy = jest.spyOn(console, 'warn');
   const warnSpy = jest.spyOn((Vue as any).util, 'warn')