chore: get rid of class-replacement hack (#13664)

We previously used a grotesque hack that would ensure the HttpError etc classes would be the same between what Vite imports via its transformation toolchain and what you get from a regular node import.

Turns out we don't need that anymore - since #9242 SvelteKit is guaranteed to always be loaded through the Vite toolchain.

Author: dummdidumm

.changeset/olive-mugs-search.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+chore: remove internal class-replacement hack that isn't needed anymore

packages/kit/src/exports/vite/dev/index.js

@@ -392,32 +392,6 @@ export async function dev(vite, vite_config, svelte_config) {
 		}
 	});
 
-	async function align_exports() {
-		// This shameful hack allows us to load runtime server code via Vite
-		// while apps load `HttpError` and `Redirect` in Node, without
-		// causing `instanceof` checks to fail
-		const control_module_node = await import('../../../runtime/control.js');
-		const control_module_vite = await vite.ssrLoadModule(`${runtime_base}/control.js`);
-
-		control_module_node.replace_implementations({
-			ActionFailure: control_module_vite.ActionFailure,
-			HttpError: control_module_vite.HttpError,
-			Redirect: control_module_vite.Redirect,
-			SvelteKitError: control_module_vite.SvelteKitError
-		});
-	}
-	await align_exports();
-	const ws_send = vite.ws.send;
-	/** @param {any} args */
-	vite.ws.send = function (...args) {
-		// We need to reapply the patch after Vite did dependency optimizations
-		// because that clears the module resolutions
-		if (args[0]?.type === 'full-reload' && args[0].path === '*') {
-			void align_exports();
-		}
-		return ws_send.apply(vite.ws, args);
-	};
-
 	vite.middlewares.use((req, res, next) => {
 		const base = `${vite.config.server.https ? 'https' : 'http'}://${
 			req.headers[':authority'] || req.headers.host

packages/kit/src/runtime/control.js

@@ -61,27 +61,3 @@ export class ActionFailure {
 		this.data = data;
 	}
 }
-
-/**
- * This is a grotesque hack that, in dev, allows us to replace the implementations
- * of these classes that you'd get by importing them from `@sveltejs/kit` with the
- * ones that are imported via Vite and loaded internally, so that instanceof
- * checks work even though SvelteKit imports this module via Vite and consumers
- * import it via Node
- * @param {{
- *   ActionFailure: typeof ActionFailure;
- *   HttpError: typeof HttpError;
- *   Redirect: typeof Redirect;
- *   SvelteKitError: typeof SvelteKitError;
- * }} implementations
- */
-export function replace_implementations(implementations) {
-	// @ts-expect-error
-	ActionFailure = implementations.ActionFailure; // eslint-disable-line no-class-assign
-	// @ts-expect-error
-	HttpError = implementations.HttpError; // eslint-disable-line no-class-assign
-	// @ts-expect-error
-	Redirect = implementations.Redirect; // eslint-disable-line no-class-assign
-	// @ts-expect-error
-	SvelteKitError = implementations.SvelteKitError; // eslint-disable-line no-class-assign
-}