fix: don't bundle @sveltejs/kit (#13971)

Rich-Harris · elliott-with-the-longest-name-on-github · teemingc · web-flow · commit bcdaf215c218 · 2025-07-09T08:26:47.000-04:00
* chore

* WIP

* WIP

* fix

* fix

* unused

* tidy up

* remove vitefu

* fix types

* changeset

* tidy up

* tidy up

* tidy up

* tidy up

* lockfile

* pacify eslint

* ignore test redirect importer for ts eslint

* don't use kit namespace import in test file

* use ts paths instead

---------

Co-authored-by: S. Elliott Johnson &lt;sejohnson@torchcloudconsulting.com&gt;
Co-authored-by: Chew Tee Ming &lt;chew.tee.ming@nindatech.com&gt;
diff --git a/.changeset/pretty-beds-melt.md b/.changeset/pretty-beds-melt.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: don't bundle `@sveltejs/kit`
diff --git a/eslint.config.js b/eslint.config.js
@@ -41,7 +41,8 @@ export default [
 			'packages/kit/test/build-errors/**/*',
 			'packages/kit/test/prerendering/**/*',
 			'packages/package/test/errors/**/*',
-			'packages/package/test/fixtures/**/*'
+			'packages/package/test/fixtures/**/*',
+			'packages/test-redirect-importer/index.js'
 		]
 	}
 ];
diff --git a/packages/kit/package.json b/packages/kit/package.json
@@ -29,8 +29,7 @@
 		"mrmime": "^2.0.0",
 		"sade": "^1.8.1",
 		"set-cookie-parser": "^2.6.0",
-		"sirv": "^3.0.0",
-		"vitefu": "^1.0.6"
+		"sirv": "^3.0.0"
 	},
 	"devDependencies": {
 		"@playwright/test": "catalog:",
@@ -84,6 +83,10 @@
 			"types": "./types/index.d.ts",
 			"import": "./src/exports/index.js"
 		},
+		"./internal": {
+			"types": "./types/index.d.ts",
+			"import": "./src/exports/internal/index.js"
+		},
 		"./node": {
 			"types": "./types/index.d.ts",
 			"import": "./src/exports/node/index.js"
diff --git a/packages/kit/src/exports/index.js b/packages/kit/src/exports/index.js
@@ -1,4 +1,4 @@
-import { HttpError, Redirect, ActionFailure } from '../runtime/control.js';
+import { HttpError, Redirect, ActionFailure } from './internal/index.js';
 import { BROWSER, DEV } from 'esm-env';
 import {
 	add_data_suffix,
diff --git a/packages/kit/src/exports/internal/index.js b/packages/kit/src/exports/internal/index.js
diff --git a/packages/kit/src/exports/node/index.js b/packages/kit/src/exports/node/index.js
@@ -1,7 +1,7 @@
 import { createReadStream } from 'node:fs';
 import { Readable } from 'node:stream';
 import * as set_cookie_parser from 'set-cookie-parser';
-import { SvelteKitError } from '../../runtime/control.js';
+import { SvelteKitError } from '../internal/index.js';
 
 /**
  * @param {import('http').IncomingMessage} req
diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
@@ -36,7 +36,6 @@ import {
 } from './module_ids.js';
 import { import_peer } from '../../utils/import.js';
 import { compact } from '../../utils/array.js';
-import { crawlFrameworkPkgs } from 'vitefu';
 
 const cwd = process.cwd();
 
@@ -229,7 +228,7 @@ async function kit({ svelte_config }) {
 		 * Build the SvelteKit-provided Vite config to be merged with the user's vite.config.js file.
 		 * @see https://vitejs.dev/guide/api-plugin.html#config
 		 */
-		async config(config, config_env) {
+		config(config, config_env) {
 			initial_config = config;
 			vite_config_env = config_env;
 			is_build = config_env.command === 'build';
@@ -252,20 +251,6 @@ async function kit({ svelte_config }) {
 
 			const generated = path.posix.join(kit.outDir, 'generated');
 
-			const packages_depending_on_svelte_kit = (
-				await crawlFrameworkPkgs({
-					root: cwd,
-					isBuild: is_build,
-					viteUserConfig: config,
-					isSemiFrameworkPkgByJson: (pkg_json) => {
-						return (
-							!!pkg_json.dependencies?.['@sveltejs/kit'] ||
-							!!pkg_json.peerDependencies?.['@sveltejs/kit']
-						);
-					}
-				})
-			).ssr.noExternal;
-
 			// dev and preview config can be shared
 			/** @type {import('vite').UserConfig} */
 			const new_config = {
@@ -299,7 +284,6 @@ async function kit({ svelte_config }) {
 						`!${kit.files.routes}/**/+*server.*`
 					],
 					exclude: [
-						'@sveltejs/kit',
 						// exclude kit features so that libraries using them work even when they are prebundled
 						// this does not affect app code, just handling of imported libraries that use $app or $env
 						'$app',
@@ -313,20 +297,7 @@ async function kit({ svelte_config }) {
 						// that bundle later on from resolving the export conditions incorrectly
 						// and for example include browser-only code in the server output
 						// because they for example use esbuild.build with `platform: 'browser'`
-						'esm-env',
-						// We need this for two reasons:
-						// 1. Without this, `@sveltejs/kit` imports are kept as-is in the server output,
-						//    and that causes modules and therefore classes like `Redirect` to be imported twice
-						//    under different IDs, which breaks a bunch of stuff because of failing instanceof checks.
-						// 2. Vitest bypasses Vite when loading external modules, so we bundle
-						//    when it is detected to keep our virtual modules working.
-						//    See https://github.com/sveltejs/kit/pull/9172
-						//    and https://vitest.dev/config/#deps-registernodeloader
-						'@sveltejs/kit',
-						// We need to bundle any packages depending on @sveltejs/kit so that
-						// everyone uses the same instances of classes such as `Redirect`
-						// which we use in `instanceof` checks
-						...packages_depending_on_svelte_kit
+						'esm-env'
 					]
 				}
 			};
diff --git a/packages/kit/src/runtime/client/client.js b/packages/kit/src/runtime/client/client.js
@@ -1,5 +1,6 @@
 import { BROWSER, DEV } from 'esm-env';
 import * as svelte from 'svelte';
+import { HttpError, Redirect, SvelteKitError } from '@sveltejs/kit/internal';
 const { onMount, tick } = svelte;
 // Svelte 4 and under don't have `untrack`, so we have to fallback if `untrack` is not exported
 const untrack = svelte.untrack ?? ((value) => value());
@@ -38,7 +39,6 @@ import {
 } from './constants.js';
 import { validate_page_exports } from '../../utils/exports.js';
 import { compact } from '../../utils/array.js';
-import { HttpError, Redirect, SvelteKitError } from '../control.js';
 import { INVALIDATED_PARAM, TRAILING_SLASH_PARAM, validate_depends } from '../shared.js';
 import { get_message, get_status } from '../../utils/error.js';
 import { writable } from 'svelte/store';
diff --git a/packages/kit/src/runtime/server/cookie.spec.js b/packages/kit/src/runtime/server/cookie.spec.js
@@ -1,6 +1,6 @@
 import { assert, expect, test } from 'vitest';
 import { domain_matches, path_matches, get_cookies } from './cookie.js';
-import { installPolyfills } from '../../exports/node/polyfills.js';
+import { installPolyfills } from '@sveltejs/kit/node/polyfills';
 
 installPolyfills();
 
diff --git a/packages/kit/src/runtime/server/data/index.js b/packages/kit/src/runtime/server/data/index.js
@@ -1,10 +1,10 @@
-import { HttpError, SvelteKitError, Redirect } from '../../control.js';
+import { text } from '@sveltejs/kit';
+import { HttpError, SvelteKitError, Redirect } from '@sveltejs/kit/internal';
 import { normalize_error } from '../../../utils/error.js';
 import { once } from '../../../utils/functions.js';
 import { load_server_data } from '../page/load_data.js';
 import { clarify_devalue_error, handle_error_and_jsonify, serialize_uses } from '../utils.js';
 import { normalize_path } from '../../../utils/url.js';
-import { text } from '../../../exports/index.js';
 import * as devalue from 'devalue';
 import { create_async_iterator } from '../../../utils/streaming.js';
 
diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
@@ -1,7 +1,7 @@
+import { Redirect } from '@sveltejs/kit/internal';
 import { ENDPOINT_METHODS, PAGE_METHODS } from '../../constants.js';
 import { negotiate } from '../../utils/http.js';
 import { with_event } from '../app/server/event.js';
-import { Redirect } from '../control.js';
 import { method_not_allowed } from './utils.js';
 
 /**
diff --git a/packages/kit/src/runtime/server/page/actions.js b/packages/kit/src/runtime/server/page/actions.js
@@ -1,9 +1,9 @@
 import * as devalue from 'devalue';
 import { DEV } from 'esm-env';
-import { json } from '../../../exports/index.js';
+import { json } from '@sveltejs/kit';
+import { HttpError, Redirect, ActionFailure, SvelteKitError } from '@sveltejs/kit/internal';
 import { get_status, normalize_error } from '../../../utils/error.js';
 import { is_form_content_type, negotiate } from '../../../utils/http.js';
-import { HttpError, Redirect, ActionFailure, SvelteKitError } from '../../control.js';
 import { handle_error_and_jsonify } from '../utils.js';
 import { with_event } from '../../app/server/event.js';
 
diff --git a/packages/kit/src/runtime/server/page/index.js b/packages/kit/src/runtime/server/page/index.js
@@ -1,8 +1,8 @@
-import { text } from '../../../exports/index.js';
+import { text } from '@sveltejs/kit';
+import { Redirect } from '@sveltejs/kit/internal';
 import { compact } from '../../../utils/array.js';
 import { get_status, normalize_error } from '../../../utils/error.js';
 import { add_data_suffix } from '../../pathname.js';
-import { Redirect } from '../../control.js';
 import { redirect_response, static_error_page, handle_error_and_jsonify } from '../utils.js';
 import {
 	handle_action_json_request,
diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
@@ -1,6 +1,7 @@
 import * as devalue from 'devalue';
 import { readable, writable } from 'svelte/store';
 import { DEV } from 'esm-env';
+import { text } from '@sveltejs/kit';
 import * as paths from '__sveltekit/paths';
 import { hash } from '../../hash.js';
 import { serialize_data } from './serialize_data.js';
@@ -9,7 +10,6 @@ import { Csp } from './csp.js';
 import { uneval_action_response } from './actions.js';
 import { clarify_devalue_error, handle_error_and_jsonify, serialize_uses } from '../utils.js';
 import { public_env, safe_public_env } from '../../shared-server.js';
-import { text } from '../../../exports/index.js';
 import { create_async_iterator } from '../../../utils/streaming.js';
 import { SVELTE_KIT_ASSETS } from '../../../constants.js';
 import { SCHEME } from '../../../utils/url.js';
diff --git a/packages/kit/src/runtime/server/page/respond_with_error.js b/packages/kit/src/runtime/server/page/respond_with_error.js
@@ -1,7 +1,7 @@
+import { Redirect } from '@sveltejs/kit/internal';
 import { render_response } from './render.js';
 import { load_data, load_server_data } from './load_data.js';
 import { handle_error_and_jsonify, static_error_page, redirect_response } from '../utils.js';
-import { Redirect } from '../../control.js';
 import { get_status } from '../../../utils/error.js';
 import { PageNodes } from '../../../utils/page_nodes.js';
 
diff --git a/packages/kit/src/runtime/server/page/server_routing.js b/packages/kit/src/runtime/server/page/server_routing.js
@@ -1,5 +1,5 @@
 import { base, assets, relative } from '__sveltekit/paths';
-import { text } from '../../../exports/index.js';
+import { text } from '@sveltejs/kit';
 import { s } from '../../../utils/misc.js';
 import { exec } from '../../../utils/routing.js';
 import { decode_params } from '../../../utils/url.js';
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
@@ -1,4 +1,6 @@
 import { DEV } from 'esm-env';
+import { json, text } from '@sveltejs/kit';
+import { HttpError, Redirect, SvelteKitError } from '@sveltejs/kit/internal';
 import { base, app_dir } from '__sveltekit/paths';
 import { is_endpoint_request, render_endpoint } from './endpoint.js';
 import { render_page } from './page/index.js';
@@ -17,9 +19,7 @@ import { redirect_json_response, render_data } from './data/index.js';
 import { add_cookies_to_headers, get_cookies } from './cookie.js';
 import { create_fetch } from './fetch.js';
 import { PageNodes } from '../../utils/page_nodes.js';
-import { HttpError, Redirect, SvelteKitError } from '../control.js';
 import { validate_server_exports } from '../../utils/exports.js';
-import { json, text } from '../../exports/index.js';
 import { action_json_redirect, is_action_json_request } from './page/actions.js';
 import { INVALIDATED_PARAM, TRAILING_SLASH_PARAM } from '../shared.js';
 import { get_public_env } from './env_module.js';
diff --git a/packages/kit/src/runtime/server/utils.js b/packages/kit/src/runtime/server/utils.js
@@ -1,8 +1,8 @@
 import { DEV } from 'esm-env';
-import { json, text } from '../../exports/index.js';
+import { json, text } from '@sveltejs/kit';
+import { HttpError } from '@sveltejs/kit/internal';
 import { coalesce_to_error, get_message, get_status } from '../../utils/error.js';
 import { negotiate } from '../../utils/http.js';
-import { HttpError } from '../control.js';
 import { fix_stack_trace } from '../shared-server.js';
 import { ENDPOINT_METHODS } from '../../constants.js';
 import { escape_html } from '../../utils/escape.js';
diff --git a/packages/kit/src/utils/error.js b/packages/kit/src/utils/error.js
@@ -1,4 +1,4 @@
-import { HttpError, SvelteKitError } from '../runtime/control.js';
+import { HttpError, SvelteKitError } from '@sveltejs/kit/internal';
 
 /**
  * @param {unknown} err
@@ -18,7 +18,7 @@ export function coalesce_to_error(err) {
  * @param {unknown} error
  */
 export function normalize_error(error) {
-	return /** @type {import('../runtime/control.js').Redirect | HttpError | SvelteKitError | Error} */ (
+	return /** @type {import('../exports/internal/index.js').Redirect | HttpError | SvelteKitError | Error} */ (
 		error
 	);
 }
diff --git a/packages/kit/test/apps/basics/_test_dependencies/redirect-pkg/index.d.ts b/packages/kit/test/apps/basics/_test_dependencies/redirect-pkg/index.d.ts
diff --git a/packages/kit/test/apps/basics/_test_dependencies/redirect-pkg/package.json b/packages/kit/test/apps/basics/_test_dependencies/redirect-pkg/package.json
diff --git a/packages/kit/test/apps/basics/package.json b/packages/kit/test/apps/basics/package.json
@@ -22,7 +22,7 @@
 		"cross-env": "catalog:",
 		"svelte": "^5.23.1",
 		"svelte-check": "^4.1.1",
-		"redirect-pkg": "file:./_test_dependencies/redirect-pkg",
+		"test-redirect-importer": "workspace:*",
 		"typescript": "^5.5.4",
 		"vite": "catalog:"
 	},
diff --git a/packages/kit/test/apps/basics/src/routes/redirect/package/+page.server.js b/packages/kit/test/apps/basics/src/routes/redirect/package/+page.server.js
@@ -1,4 +1,4 @@
-import { authenticate } from 'redirect-pkg';
+import { authenticate } from 'test-redirect-importer';
 
 export function load() {
 	authenticate('/redirect/c');
diff --git a/packages/kit/tsconfig.json b/packages/kit/tsconfig.json
@@ -11,6 +11,8 @@
 		"paths": {
 			"@sveltejs/kit": ["./src/exports/public.d.ts"],
 			"@sveltejs/kit/node": ["./src/exports/node/index.js"],
+			"@sveltejs/kit/node/polyfills": ["./src/exports/node/polyfills.js"],
+			"@sveltejs/kit/internal": ["./src/exports/internal/index.js"],
 			// internal use only
 			"types": ["./src/types/internal.d.ts"]
 		},
diff --git a/packages/test-redirect-importer/index.js b/packages/test-redirect-importer/index.js
@@ -1,5 +1,8 @@
 import { redirect } from '@sveltejs/kit';
 
+// This exists to check that an external package importing `redirect`
+// will get something that satisfies the relevant `instanceof` checks
+
 /**
  * @param {string} redirectUrl
  * @returns {never}
diff --git a/packages/test-redirect-importer/package.json b/packages/test-redirect-importer/package.json
@@ -0,0 +1,12 @@
+{
+	"name": "test-redirect-importer",
+	"version": "0.0.1",
+	"private": true,
+	"type": "module",
+	"exports": {
+		".": "./index.js"
+	},
+	"dependencies": {
+		"@sveltejs/kit": "workspace:*"
+	}
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'@sveltejs/kit': patch
 +---
++
 +fix: don't bundle `@sveltejs/kit`
Original file line number	Diff line number	Diff line change
`@@ -41,7 +41,8 @@ export default [`
`41`	`41`	`'packages/kit/test/build-errors/*/',`
`42`	`42`	`'packages/kit/test/prerendering/*/',`
`43`	`43`	`'packages/package/test/errors/*/',`
`44`		`- 'packages/package/test/fixtures/*/'`
	`44`	`+ 'packages/package/test/fixtures/*/',`
	`45`	`+ 'packages/test-redirect-importer/index.js'`
`45`	`46`	`]`
`46`	`47`	`}`
`47`	`48`	`];`
Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-import { HttpError, Redirect, ActionFailure } from '../runtime/control.js';`
	`1`	`+import { HttpError, Redirect, ActionFailure } from './internal/index.js';`
`2`	`2`	`import { BROWSER, DEV } from 'esm-env';`
`3`	`3`	`import {`
`4`	`4`	`add_data_suffix,`