feat: lazy discovery of remote functions (#14293)

* WIP lazy discovery of remote functions

* fix

* partial fix

* some progress

* WIP

* tweak

* working but messy

* WIP

* WIP

* unused

* WIP

* more

* tidy up

* fix adapter, make self-contained

* regenerate

* fix

* changeset

Author: Rich-Harris

.changeset/clear-wolves-worry.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': minor
+---
+
+feat: lazy discovery of remote functions

packages/kit/src/core/adapt/builder.js

@@ -1,7 +1,7 @@
 /** @import { Builder } from '@sveltejs/kit' */
 /** @import { ResolvedConfig } from 'vite' */
 /** @import { RouteDefinition } from '@sveltejs/kit' */
-/** @import { RouteData, ValidatedConfig, BuildData, ServerMetadata, ServerMetadataRoute, Prerendered, PrerenderMap, Logger } from 'types' */
+/** @import { RouteData, ValidatedConfig, BuildData, ServerMetadata, ServerMetadataRoute, Prerendered, PrerenderMap, Logger, RemoteChunk } from 'types' */
 import colors from 'kleur';
 import { createReadStream, createWriteStream, existsSync, statSync } from 'node:fs';
 import { extname, resolve, join, dirname, relative } from 'node:path';
@@ -32,6 +32,7 @@ const extensions = ['.html', '.js', '.mjs', '.json', '.css', '.svg', '.xml', '.w
  *   prerender_map: PrerenderMap;
  *   log: Logger;
  *   vite_config: ResolvedConfig;
+ *   remotes: RemoteChunk[]
  * }} opts
  * @returns {Builder}
  */
@@ -43,7 +44,8 @@ export function create_builder({
 	prerendered,
 	prerender_map,
 	log,
-	vite_config
+	vite_config,
+	remotes
 }) {
 	/** @type {Map<RouteDefinition, RouteData>} */
 	const lookup = new Map();
@@ -145,7 +147,8 @@ export function create_builder({
 								build_data,
 								prerendered: [],
 								relative_path: relativePath,
-								routes: Array.from(filtered)
+								routes: Array.from(filtered),
+								remotes
 							})
 					});
 				}
@@ -195,7 +198,8 @@ export function create_builder({
 				relative_path: relativePath,
 				routes: subset
 					? subset.map((route) => /** @type {import('types').RouteData} */ (lookup.get(route)))
-					: route_data.filter((route) => prerender_map.get(route.id) !== true)
+					: route_data.filter((route) => prerender_map.get(route.id) !== true),
+				remotes
 			});
 		},
 

packages/kit/src/core/adapt/index.js

@@ -8,6 +8,7 @@ import { create_builder } from './builder.js';
  * @param {import('types').Prerendered} prerendered
  * @param {import('types').PrerenderMap} prerender_map
  * @param {import('types').Logger} log
+ * @param {import('types').RemoteChunk[]} remotes
  * @param {import('vite').ResolvedConfig} vite_config
  */
 export async function adapt(
@@ -17,6 +18,7 @@ export async function adapt(
 	prerendered,
 	prerender_map,
 	log,
+	remotes,
 	vite_config
 ) {
 	// This is only called when adapter is truthy, so the cast is safe
@@ -32,6 +34,7 @@ export async function adapt(
 		prerendered,
 		prerender_map,
 		log,
+		remotes,
 		vite_config
 	});
 

packages/kit/src/core/generate_manifest/index.js

@@ -1,3 +1,4 @@
+/** @import { RemoteChunk } from 'types' */
 import fs from 'node:fs';
 import path from 'node:path';
 import * as mime from 'mrmime';
@@ -18,9 +19,10 @@ import { uneval } from 'devalue';
  *   prerendered: string[];
  *   relative_path: string;
  *   routes: import('types').RouteData[];
+ *   remotes: RemoteChunk[];
  * }} opts
  */
-export function generate_manifest({ build_data, prerendered, relative_path, routes }) {
+export function generate_manifest({ build_data, prerendered, relative_path, routes, remotes }) {
 	/**
 	 * @type {Map<any, number>} The new index of each node in the filtered nodes array
 	 */
@@ -101,7 +103,7 @@ export function generate_manifest({ build_data, prerendered, relative_path, rout
 					${(node_paths).map(loader).join(',\n')}
 				],
 				remotes: {
-					${build_data.manifest_data.remotes.map((remote) => `'${remote.hash}': ${loader(join_relative(relative_path, resolve_symlinks(build_data.server_manifest, remote.file).chunk.file))}`).join(',\n')}
+					${remotes.map((remote) => `'${remote.hash}': ${loader(join_relative(relative_path, `chunks/remote-${remote.hash}.js`))}`).join(',\n')}
 				},
 				routes: [
 					${routes.map(route => {

packages/kit/src/core/postbuild/analyse.js

@@ -1,3 +1,4 @@
+/** @import { RemoteChunk } from 'types' */
 import { join } from 'node:path';
 import { pathToFileURL } from 'node:url';
 import { validate_server_exports } from '../../utils/exports.js';
@@ -11,7 +12,6 @@ import { check_feature } from '../../utils/features.js';
 import { createReadableStream } from '@sveltejs/kit/node';
 import { PageNodes } from '../../utils/page_nodes.js';
 import { build_server_nodes } from '../../exports/vite/build/build_server.js';
-import { validate_remote_functions } from '@sveltejs/kit/internal';
 
 export default forked(import.meta.url, analyse);
 
@@ -25,6 +25,7 @@ export default forked(import.meta.url, analyse);
  *   env: Record<string, string>;
  *   out: string;
  *   output_config: import('types').RecursiveRequired<import('types').ValidatedConfig['kit']['output']>;
+ *   remotes: RemoteChunk[];
  * }} opts
  */
 async function analyse({
@@ -35,7 +36,8 @@ async function analyse({
 	tracked_features,
 	env,
 	out,
-	output_config
+	output_config,
+	remotes
 }) {
 	/** @type {import('@sveltejs/kit').SSRManifest} */
 	const manifest = (await import(pathToFileURL(manifest_path).href)).manifest;
@@ -166,16 +168,14 @@ async function analyse({
 	}
 
 	// analyse remotes
-	for (const remote of manifest_data.remotes) {
+	for (const remote of remotes) {
 		const loader = manifest._.remotes[remote.hash];
-		const module = await loader();
-
-		validate_remote_functions(module, remote.file);
+		const { default: functions } = await loader();
 
 		const exports = new Map();
 
-		for (const name in module) {
-			const info = /** @type {import('types').RemoteInfo} */ (module[name].__);
+		for (const name in functions) {
+			const info = /** @type {import('types').RemoteInfo} */ (functions[name].__);
 			const type = info.type;
 
 			exports.set(name, {

packages/kit/src/core/postbuild/prerender.js

@@ -495,7 +495,7 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env }) {
 	for (const loader of Object.values(manifest._.remotes)) {
 		const module = await loader();
 
-		for (const fn of Object.values(module)) {
+		for (const fn of Object.values(module.default)) {
 			if (fn?.__?.type === 'prerender') {
 				prerender_functions.push(fn.__);
 				should_prerender = true;

packages/kit/src/core/sync/create_manifest_data/index.js

@@ -4,11 +4,10 @@ import process from 'node:process';
 import colors from 'kleur';
 import { lookup } from 'mrmime';
 import { list_files, runtime_directory } from '../../utils.js';
-import { posixify, resolve_entry, walk } from '../../../utils/filesystem.js';
+import { posixify, resolve_entry } from '../../../utils/filesystem.js';
 import { parse_route_id } from '../../../utils/routing.js';
 import { sort_routes } from './sort.js';
 import { isSvelte5Plus } from '../utils.js';
-import { hash } from '../../../utils/hash.js';
 
 /**
  * Generates the manifest data used for the client-side manifest and types generation.
@@ -28,7 +27,6 @@ export default function create_manifest_data({
 	const hooks = create_hooks(config, cwd);
 	const matchers = create_matchers(config, cwd);
 	const { nodes, routes } = create_routes_and_nodes(cwd, config, fallback);
-	const remotes = create_remotes(config, cwd);
 
 	for (const route of routes) {
 		for (const param of route.params) {
@@ -43,7 +41,6 @@ export default function create_manifest_data({
 		hooks,
 		matchers,
 		nodes,
-		remotes,
 		routes
 	};
 }
@@ -468,33 +465,6 @@ function create_routes_and_nodes(cwd, config, fallback) {
 	};
 }
 
-/**
- * @param {import('types').ValidatedConfig} config
- * @param {string} cwd
- */
-function create_remotes(config, cwd) {
-	if (!config.kit.experimental.remoteFunctions) return [];
-
-	const extensions = config.kit.moduleExtensions.map((ext) => `.remote${ext}`);
-
-	/** @type {import('types').ManifestData['remotes']} */
-	const remotes = [];
-
-	// TODO could files live in other directories, including node_modules?
-	for (const file of walk(config.kit.files.src)) {
-		if (extensions.some((ext) => file.endsWith(ext))) {
-			const posixified = posixify(path.relative(cwd, `${config.kit.files.src}/${file}`));
-
-			remotes.push({
-				hash: hash(posixified),
-				file: posixified
-			});
-		}
-	}
-
-	return remotes;
-}
-
 /**
  * @param {string} project_relative
  * @param {string} file

packages/kit/src/exports/internal/index.js

@@ -62,4 +62,4 @@ export class ActionFailure {
 	}
 }
 
-export { validate_remote_functions } from './remote-functions.js';
+export { init_remote_functions } from './remote-functions.js';

packages/kit/src/exports/internal/remote-functions.js

@@ -1,27 +1,28 @@
+/** @import { RemoteInfo } from 'types' */
+
+/** @type {RemoteInfo['type'][]} */
+const types = ['command', 'form', 'prerender', 'query', 'query_batch'];
+
 /**
  * @param {Record<string, any>} module
  * @param {string} file
+ * @param {string} hash
  */
-export function validate_remote_functions(module, file) {
+export function init_remote_functions(module, file, hash) {
 	if (module.default) {
 		throw new Error(
 			`Cannot export \`default\` from a remote module (${file}) — please use named exports instead`
 		);
 	}
 
-	for (const name in module) {
-		const type = /** @type {import('types').RemoteInfo['type']} */ (module[name]?.__?.type);
-
-		if (
-			type !== 'form' &&
-			type !== 'command' &&
-			type !== 'query' &&
-			type !== 'query_batch' &&
-			type !== 'prerender'
-		) {
+	for (const [name, fn] of Object.entries(module)) {
+		if (!types.includes(fn?.__?.type)) {
 			throw new Error(
 				`\`${name}\` exported from ${file} is invalid — all exports from this file must be remote functions`
 			);
 		}
+
+		fn.__.id = `${hash}/${name}`;
+		fn.__.name = name;
 	}
 }