Describe the bug

Upgrading svelte from 5.43.14 to 5.44.0 causes async rendering to fail, throwing the server_context_required error. We still call render() in what seems an okay way so I'm not sure what we should do about: https://github.com/withastro/astro/blob/main/packages/integrations/svelte/src/server.ts#L58.

Reproduction

• Clone https://github.com/withastro/astro/
• Checkout to fix/svelte-server-context-required
• pnpm i --frozen-lockfile
• pnpm build
• node --test packages/integrations/svelte/test/async-rendering.test.js

Logs

https://github.com/withastro/astro/actions/runs/20025261175/job/57421186982?pr=14979#step:8:78

System Info

Irrelevant, occurs on all OSs for various node versions. See withastro/astro#14979

Severity

blocking an upgrade