Incorrect response `status code` when throwing error from `+server.ts`

Describe the bug

When throwing an error from a +server.ts route, the status code in the response header is set to 500 instead of the status code specified in the error() helper. The nearest Error Boundary does render and the error property in the $page store does have the correct status code, however the response header doesn’t match.

Reproduction

+server.ts

import { error } from '@sveltejs/kit';
import type { RequestHandler } from './$types';

const shortcodes: { [index: string]: string } = {
	microsoft: 'https://www.microsoft.com',
	google: 'https://www.google.com'
};

export const GET: RequestHandler = ({ params }) => {
	if (!params.shortcode || !shortcodes[params.shortcode]) {
		throw error(404, 'Shortcode not found');
	}

	return Response.redirect(shortcodes[params.shortcode], 301);
};

Response Header

Status Code: 500 Internal Server Error

$page store

{
  error: HttpError {
    name: 'HttpError',
    stack: undefined,
    status: 404,
    message: 'Shortcode Not Found'
  },
  params: { shortcode: 'test' },
  routeId: '[shortcode]',
  status: 500,
  url: URL {
    href: 'http://localhost:5173/test',
    origin: 'http://localhost:5173',
    protocol: 'http:',
    username: '',
    password: '',
    host: 'localhost:5173',
    hostname: 'localhost',
    port: '5173',
    pathname: '/test',
    search: '',
    searchParams: URLSearchParams {},
    hash: ''
  },
  data: {}
}

Logs

No response

System Info

System:
    OS: macOS 12.5
    CPU: (10) arm64 Apple M1 Max
    Memory: 5.49 GB / 32.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 18.7.0 - /opt/homebrew/bin/node
    npm: 8.16.0 - /opt/homebrew/bin/npm
  Browsers:
    Brave Browser: 104.1.42.95
    Chrome: 104.0.5112.79
    Firefox Developer Edition: 104.0
    Safari: 15.6
    Safari Technology Preview: 16.0
  npmPackages:
    @sveltejs/adapter-auto: next => 1.0.0-next.64
    @sveltejs/kit: next => 1.0.0-next.417
    svelte: ^3.44.0 => 3.49.0
    vite: ^3.0.0 => 3.0.8

Severity

serious, but I can work around it

Additional Information

No response

[Conduitry]

This is the intended behavior. throw error() or throw redirect() are intended for use in load functions. In a +server.js endpoint handler, you should just directly return the Response object with whatever error response you want. Any thrown exception results in a 500.

Perhaps there could be a dev mode warning that makes this more clear - but I don’t think we want to start having special handling for certain thrown errors in +server.js files.

[dummdidumm]

Since we agreed that error and redirect are valid to throw in +server.js, this should work. However, the obeserved behavior (nearest error page is rendered, page is shown) is also wrong (as a consequence of this bug) in my opinion. Instead you should get a blank page with just the error message. If you are requesting an endpoint directly, it’s not something that is part of the page - and you get the same behavior if you do return new Response('Shortcode not found', { status: 404 }).