fix(reactivity): effect shoud only recursively self trigger with explicit options

fix #2125

packages/runtime-core/__tests__/apiWatch.spec.ts

@@ -779,4 +779,17 @@ describe('api: watch', () => {
     // should trigger now
     expect(sideEffect).toBe(2)
   })
+
+  // #2125
+  test('watchEffect should not recursively trigger itself', async () => {
+    const spy = jest.fn()
+    const price = ref(10)
+    const history = ref<number[]>([])
+    watchEffect(() => {
+      history.value.push(price.value)
+      spy()
+    })
+    await nextTick()
+    expect(spy).toHaveBeenCalledTimes(1)
+  })
 })

packages/runtime-core/__tests__/rendererComponent.spec.ts

@@ -5,7 +5,10 @@ import {
   nodeOps,
   serializeInner,
   nextTick,
-  VNode
+  VNode,
+  provide,
+  inject,
+  Ref
 } from '@vue/runtime-test'
 
 describe('renderer: component', () => {
@@ -104,4 +107,34 @@ describe('renderer: component', () => {
     )
     expect(Comp1.updated).not.toHaveBeenCalled()
   })
+
+  // #2043
+  test('component child synchronously updating parent state should trigger parent re-render', async () => {
+    const App = {
+      setup() {
+        const n = ref(0)
+        provide('foo', n)
+        return () => {
+          return [h('div', n.value), h(Child)]
+        }
+      }
+    }
+
+    const Child = {
+      setup() {
+        const n = inject<Ref<number>>('foo')!
+        n.value++
+
+        return () => {
+          return h('div', n.value)
+        }
+      }
+    }
+
+    const root = nodeOps.createElement('div')
+    render(h(App), root)
+    expect(serializeInner(root)).toBe(`<div>0</div><div>1</div>`)
+    await nextTick()
+    expect(serializeInner(root)).toBe(`<div>1</div><div>1</div>`)
+  })
 })