fix: When the app is unmounted, the onMounted of suspense in Transition should not be called

packages/runtime-core/src/components/Suspense.ts

@@ -552,6 +552,7 @@ function createSuspenseBoundary(
               )
               queuePostFlushCb(effects)
             }
+            activeBranch!.transition!.afterLeave = undefined
           }
         }
         // unmount current active tree

packages/runtime-dom/__tests__/createApp.spec.ts

@@ -1,4 +1,5 @@
-import { createApp, h } from '../src'
+import { createApp, h, ref } from '../src'
+import { defineComponent, onMounted, shallowRef } from 'vue'
 
 describe('createApp for dom', () => {
   // #2926
@@ -39,4 +40,62 @@ describe('createApp for dom', () => {
     // ensure no mutation happened to Root object
     expect(originalObj).toMatchObject(Root)
   })
+
+  test('When the app is unmounted, the onMounted of suspense in Transition should not be called', async () => {
+    const onPage2Mounted = vi.fn()
+    let page1Comp: any
+    const Page1 = defineComponent({
+      name: 'Page1',
+      setup() {
+        return () => h('div', null, 'page1')
+      },
+    })
+    const Page2 = defineComponent({
+      name: 'Page2',
+      setup() {
+        onMounted(onPage2Mounted)
+        return () => h('div', null, 'page2')
+      },
+    })
+    const Component = shallowRef(Page1)
+    const page = ref<any>(null)
+    const App = defineComponent({
+      setup() {
+        return {
+          Component,
+          page,
+        }
+      },
+      template: `
+          <div>
+            <template v-if="Component">
+                <transition :duration="300" mode="out-in" appear>
+                  <keep-alive :include="['Page1', 'Page2']">
+                    <suspense>
+                      <component ref="page" :is="Component" :key="Component.name"></component>
+                    </suspense>
+                  </keep-alive>
+                </transition>
+              </template>
+          </div>
+        `,
+    })
+    const app = createApp(App)
+    app.mount(document.createElement('div'))
+    await new Promise(resolve => {
+      setTimeout(resolve, 500)
+    })
+    page1Comp = page.value
+    Component.value = Page2
+    await new Promise(resolve => {
+      setTimeout(resolve, 500)
+    })
+    expect(onPage2Mounted).toHaveBeenCalledTimes(1)
+    app.unmount()
+    await new Promise(resolve => {
+      setTimeout(resolve, 500)
+    })
+    expect(onPage2Mounted).toHaveBeenCalledTimes(1)
+    expect(page1Comp._.vnode.transition.afterLeave).toBe(undefined)
+  })
 })