SvelteKit Bug: command() returns null for event.route.id on rerouted pages

Description

When using SvelteKit's experimental command() (remote functions) from a page that is served via a reroute hook, event.route.id inside the command is null instead of the matched route.

Page navigation correctly resolves event.route.id via the reroute hook. But when a command() is invoked from that same page, event.route.id is null.

Setup

pnpm install
pnpm dev

How to reproduce

1. Start the dev server with pnpm dev
2. Navigate to http://localhost:5173/original
   • The page loads correctly — the reroute hook maps /original → /actual
   • In the terminal, you'll see: [hooks.server] GET /original → route.id: /actual
3. Click the "Call command()" button
4. Observe the result displayed on the page

Expected behavior

event.route.id → /actual (same as during page navigation)

Actual behavior

event.route.id → null

Navigate to /actual directly and click the button to verify — in that case event.route.id is correctly /actual.

Real-world impact

This breaks any handle hook logic that uses event.route.id for command() requests. In our production app we use subdomain-based routing via reroute:

// hooks.ts — reroutes acme.example.com/ → /o/acme
export const reroute: Reroute = ({ url }) => {
  const subdomain = getSubdomain(url.hostname);
  if (subdomain) return `/o/${subdomain}${url.pathname}`;
};

// hooks.server.ts — skips auth for static marketing pages
const handleAuth: Handle = async ({ event, resolve }) => {
  if (event.route.id?.includes('(static)')) return resolve(event);
  // ... set up session ...
};

When a command() is called from acme.example.com/, event.route.id is null instead of /o/[slug]. In our case the un-rerouted / path happened to match a /(static) route group, causing the auth hook to skip session setup.

Key files

• src/hooks.ts — the reroute hook that maps /original → /actual
• src/hooks.server.ts — logs every request's route.id and url.pathname
• src/routes/actual/+page.svelte — page with a button that calls a command()
• src/lib/get-route-info.remote.ts — the server command() that returns event.route and event.url

Environment

• SvelteKit 2.55.0
• Svelte 5.53.13
• Vite 8.0.0
• TypeScript 5.9.3