Vue version

3.5.32

Link to minimal reproduction

https://stackblitz.com/edit/vitejs-vite-zqf6g74x?file=src%2Fcomponents%2FComponentA.vue&terminal=dev

Steps to reproduce

1. download the reproduction from stackblitz (won't work there)
2. run pnpm i && pnpm ssr
3. see the heap size & alive app instances grow with each request

The script creates 1000 fresh ssr apps, renders them to string and tracks whether each of them gets garbage-collected.

2 sibling async SFC components with top-level await are needed for this to reproduce. One of them needs to capture a stop handle for an immediate watcher, which then ends up keeping the whole scope in memory and through it, the whole app. (probably)

ComponentA

<script setup>
    const enabled = await Promise.resolve(false)
    const el = ref(null)
    const stopWatch = watch(() => el.value, () => {}, { immediate: true })  // actually runs on the server
    onScopeDispose(() => { stopWatch() })
</script>

<template>
    <div ref="el">Component A {{ enabled }}</div>
</template>

Component B

<script setup>
    const enabled = await Promise.resolve(false)
</script>

<template>
    <div>Component B {{ enabled }}</div>
</template>

app:

<template>
    <div>
        <ComponentA />
        <ComponentB />
    </div>
</template>

What is expected?

All apps should get garbage collected.

What is actually happening?

Every app is kept in memory forever:

FINAL: created=10000 finalized=0 alive=10000

System Info

Any additional comments?

Maybe related to #14674?

In some cases, this can cause the whole NuxtApp to be kept in memory in Nuxt, along with all the rendered server payload, which adds up very quickly.