fix(runtime-vapor): relay vdom transition hooks to a child's root rendered after its async setup

packages/runtime-vapor/__tests__/components/Transition.spec.ts

@@ -3799,6 +3799,8 @@ describe('a child rendering its root after the hooks were applied, like vdom', (
     content: string,
     init: Record<string, any>,
     steps: Step[],
+    // the Transition stays vdom: its hooks are relayed to the vapor child
+    vdomHost = false,
   ) {
     const srcs: Record<string, string> = {
       Item: `<template><div class="item">item</div></template>`,
@@ -3848,7 +3850,7 @@ describe('a child rendering its root after the hooks were applied, like vdom', (
           : `<script setup>const data = _data; const components = _components;</script>` +
             srcs[name]
         components[name] = compile(src, data, components, {
-          vapor: vapor && name !== 'App',
+          vapor: vapor && name !== 'App' && !(vdomHost && name === 'Host'),
         })
       }
       const load = () => Promise.resolve(components.Item)
@@ -3909,4 +3911,16 @@ describe('a child rendering its root after the hooks were applied, like vdom', (
         ['ready', 'off', 'done'],
       ),
   )
+
+  describe.each(['out-in', 'in-out', 'default'])(
+    'under a vdom Transition, %s',
+    mode => {
+      test.each([
+        ['an async setup component', children['an async setup component']],
+        ['a component rooted in one', children['a component rooted in one']],
+      ])('%s enters once its setup resolves', (_, content) =>
+        parity(mode, content, { show: false }, ['on', 'done'], true),
+      )
+    },
+  )
 })

packages/runtime-vapor/src/components/Transition.ts

@@ -1151,8 +1151,8 @@ function collectComponentTransitionBlocks(
     block.asyncDep &&
     !block.asyncResolved
   ) {
-    if (ctx) {
-      if (onFragment) onFragment(block)
+    if (onFragment) {
+      onFragment(block)
       resolveRootAfterSetup(block, ctx)
     }
     return
@@ -1181,9 +1181,10 @@ function collectComponentTransitionBlocks(
   collectTransitionBlocks(block.block, onFragment, children, ctx)
 }
 
+// `ctx` undefined: hooks relayed from a vdom Transition, resolving no identity
 function resolveRootAfterSetup(
   instance: VaporComponentInstance & TransitionOptions,
-  ctx: KeyContext,
+  ctx: KeyContext | undefined,
 ): void {
   // one callback per instance: a later walk only updates the context it uses
   if (!keyContexts.has(instance)) {
@@ -1200,8 +1201,10 @@ function resolveRootAfterSetup(
         )
       }
     })
+    keyContexts.set(instance, ctx || ROOT_KEY_CONTEXT)
+  } else if (ctx) {
+    keyContexts.set(instance, ctx)
   }
-  keyContexts.set(instance, ctx)
 }
 
 function collectArrayTransitionBlocks(