chore: separate generated from non-generated server code (#8429)

* rename node.server to node.has_server_load - more descriptive

* rename core/prerender to core/postbuild

* fix

* move logic around

* rename server/index.js to server/respond.js

* move some logic around

* move some stuff around

* remove options.paths

* move read to internal request options

* remove version from SSROptions

* tidy up

* add note

* tidy up

* remove public_env from SSROptions

* move logic to sync

* notes to self

* WIP

* hack around the problem

* oops

* partial solution to stack traces

* fix a few more tests

* insane

* use __SVELTEKIT_DEV__ instead of state.dev

* fix

* set globalThis.__SVELTEKIT_DEV__

* tidy some stuff up

* add ambient declaration

* set paths correctly

* remove import

* DRY

* reduce indirection

* use private fields

* separate manifest from server configuration

* tidy up

* exclude SvelteKit deps from Vite processing

* regenerate server-internal.js as necessary

* tidy up

* see if this fixes windows

* of course it's a path separator issue

* remove unused exports

* tidy up, see if this still works in windows

* remove some unused code

* Create gorgeous-actors-run.md

Co-authored-by: Simon Holthausen <[email protected]>

.changeset/gorgeous-actors-run.md

@@ -0,0 +1,5 @@
+---
+"@sveltejs/kit": patch
+---
+
+chore: separate generated from non-generated server code

.prettierrc

@@ -25,7 +25,7 @@
 				"packages/package/test/fixtures/**/expected/**/*",
 				"packages/package/test/watch/expected/**/*",
 				"packages/package/test/watch/package/**/*",
-				"packages/kit/src/core/prerender/fixtures/**/*",
+				"packages/kit/src/core/postbuild/fixtures/**/*",
 				"packages/migrate/migrations/routes/*/samples.md"
 			],
 			"options": {

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

@@ -126,7 +126,7 @@ export function create_builder({ config, build_data, routes, prerendered, log })
 
 		generateFallback(dest) {
 			// do prerendering in a subprocess so any dangling stuff gets killed upon completion
-			const script = fileURLToPath(new URL('../prerender/fallback.js', import.meta.url));
+			const script = fileURLToPath(new URL('../postbuild/fallback.js', import.meta.url));
 
 			const manifest_path = `${config.kit.outDir}/output/server/manifest-full.js`;
 

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

@@ -14,17 +14,19 @@ installPolyfills();
 
 const server_root = join(config.outDir, 'output');
 
+/** @type {import('types').ServerInternalModule} */
+const { set_building, set_paths } = await import(
+	pathToFileURL(`${server_root}/server/internal.js`).href
+);
+
 /** @type {import('types').ServerModule} */
-const { Server, override } = await import(pathToFileURL(`${server_root}/server/index.js`).href);
+const { Server } = await import(pathToFileURL(`${server_root}/server/index.js`).href);
 
 /** @type {import('types').SSRManifest} */
 const manifest = (await import(pathToFileURL(manifest_path).href)).manifest;
 
-override({
-	building: true,
-	paths: config.paths,
-	read: (file) => readFileSync(join(config.files.assets, file))
-});
+set_building(true);
+set_paths(config.paths);
 
 const server = new Server(manifest);
 await server.init({ env: JSON.parse(env) });
@@ -36,7 +38,8 @@ const rendered = await server.respond(new Request(config.prerender.origin + '/[f
 	prerendering: {
 		fallback: true,
 		dependencies: new Map()
-	}
+	},
+	read: (file) => readFileSync(join(config.files.assets, file))
 });
 
 mkdirp(dirname(dest));

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

@@ -0,0 +1,104 @@
+import { writeFileSync } from 'fs';
+import { join } from 'path';
+import { pathToFileURL } from 'url';
+import { get_option } from '../../runtime/server/utils.js';
+import {
+	validate_common_exports,
+	validate_page_server_exports,
+	validate_server_exports
+} from '../../utils/exports.js';
+import { load_config } from '../config/index.js';
+import { prerender } from './prerender.js';
+
+const [, , client_out_dir, manifest_path, results_path, verbose, env] = process.argv;
+
+/** @type {import('types').SSRManifest} */
+const manifest = (await import(pathToFileURL(manifest_path).href)).manifest;
+
+/** @type {import('types').PrerenderMap} */
+const prerender_map = new Map();
+
+/** @type {import('types').ValidatedKitConfig} */
+const config = (await load_config()).kit;
+
+const server_root = join(config.outDir, 'output');
+
+/** @type {import('types').ServerInternalModule} */
+const internal = await import(pathToFileURL(`${server_root}/server/internal.js`).href);
+
+/** @type {import('types').ServerModule} */
+const { Server } = await import(pathToFileURL(`${server_root}/server/index.js`).href);
+
+// configure `import { building } from '$app/environment'` —
+// essential we do this before analysing the code
+internal.set_building(true);
+
+// analyse routes
+for (const route of manifest._.routes) {
+	if (route.endpoint) {
+		const mod = await route.endpoint();
+		if (mod.prerender !== undefined) {
+			validate_server_exports(mod, route.id);
+
+			if (mod.prerender && (mod.POST || mod.PATCH || mod.PUT || mod.DELETE)) {
+				throw new Error(
+					`Cannot prerender a +server file with POST, PATCH, PUT, or DELETE (${route.id})`
+				);
+			}
+
+			prerender_map.set(route.id, mod.prerender);
+		}
+	}
+
+	if (route.page) {
+		const nodes = await Promise.all(
+			[...route.page.layouts, route.page.leaf].map((n) => {
+				if (n !== undefined) return manifest._.nodes[n]();
+			})
+		);
+
+		const layouts = nodes.slice(0, -1);
+		const page = nodes.at(-1);
+
+		for (const layout of layouts) {
+			if (layout) {
+				validate_common_exports(layout.server, route.id);
+				validate_common_exports(layout.universal, route.id);
+			}
+		}
+
+		if (page) {
+			validate_page_server_exports(page.server, route.id);
+			validate_common_exports(page.universal, route.id);
+		}
+
+		const should_prerender = get_option(nodes, 'prerender');
+		const prerender =
+			should_prerender === true ||
+			// Try prerendering if ssr is false and no server needed. Set it to 'auto' so that
+			// the route is not removed from the manifest, there could be a server load function.
+			// People can opt out of this behavior by explicitly setting prerender to false
+			(should_prerender !== false && get_option(nodes, 'ssr') === false && !page?.server?.actions
+				? 'auto'
+				: should_prerender ?? false);
+
+		prerender_map.set(route.id, prerender);
+	}
+}
+
+const { prerendered } = await prerender({
+	Server,
+	internal,
+	manifest,
+	prerender_map,
+	client_out_dir,
+	verbose,
+	env
+});
+
+writeFileSync(
+	results_path,
+	JSON.stringify({ prerendered, prerender_map }, (_key, value) =>
+		value instanceof Map ? Array.from(value.entries()) : value
+	)
+);

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

@@ -1,6 +1,6 @@
 import { readFileSync, writeFileSync } from 'fs';
 import { dirname, join } from 'path';
-import { pathToFileURL, URL } from 'url';
+import { URL } from 'url';
 import { installPolyfills } from '../../exports/node/polyfills.js';
 import { mkdirp, posixify, walk } from '../../utils/filesystem.js';
 import { should_polyfill } from '../../utils/platform.js';
@@ -11,16 +11,6 @@ import { escape_html_attr } from '../../utils/escape.js';
 import { logger } from '../utils.js';
 import { load_config } from '../config/index.js';
 import { get_route_segments } from '../../utils/routing.js';
-import { get_option } from '../../runtime/server/utils.js';
-import {
-	validate_common_exports,
-	validate_page_server_exports,
-	validate_server_exports
-} from '../../utils/exports.js';
-
-const [, , client_out_dir, manifest_path, results_path, verbose, env] = process.argv;
-
-prerender();
 
 /**
  * @template {{message: string}} T
@@ -52,22 +42,27 @@ const OK = 2;
 const REDIRECT = 3;
 
 /**
+ *
  * @param {{
- *   prerendered: import('types').Prerendered;
+ *   Server: typeof import('types').InternalServer;
+ *   internal: import('types').ServerInternalModule;
+ *   manifest: import('types').SSRManifest;
  *   prerender_map: import('types').PrerenderMap;
- * }} data
+ *   client_out_dir: string;
+ *   verbose: string;
+ *   env: string;
+ * }} opts
+ * @returns
  */
-const output_and_exit = (data) => {
-	writeFileSync(
-		results_path,
-		JSON.stringify(data, (_key, value) =>
-			value instanceof Map ? Array.from(value.entries()) : value
-		)
-	);
-	process.exit(0);
-};
-
-export async function prerender() {
+export async function prerender({
+	Server,
+	internal,
+	manifest,
+	prerender_map,
+	client_out_dir,
+	verbose,
+	env
+}) {
 	/** @type {import('types').Prerendered} */
 	const prerendered = {
 		pages: new Map(),
@@ -76,9 +71,6 @@ export async function prerender() {
 		paths: []
 	};
 
-	/** @type {import('types').PrerenderMap} */
-	const prerender_map = new Map();
-
 	/** @type {Set<string>} */
 	const prerendered_routes = new Set();
 
@@ -94,29 +86,10 @@ export async function prerender() {
 		installPolyfills();
 	}
 
-	const server_root = join(config.outDir, 'output');
-
-	/** @type {import('types').ServerModule} */
-	const { Server, override } = await import(pathToFileURL(`${server_root}/server/index.js`).href);
-
-	/** @type {import('types').SSRManifest} */
-	const manifest = (await import(pathToFileURL(manifest_path).href)).manifest;
-
 	/** @type {Map<string, string>} */
 	const saved = new Map();
 
-	override({
-		building: true,
-		paths: config.paths,
-		read: (file) => {
-			// stuff we just wrote
-			const filepath = saved.get(file);
-			if (filepath) return readFileSync(filepath);
-
-			// stuff in `static`
-			return readFileSync(join(config.files.assets, file));
-		}
-	});
+	internal.set_paths(config.paths);
 
 	const server = new Server(manifest);
 	await server.init({ env: JSON.parse(env) });
@@ -201,9 +174,19 @@ export async function prerender() {
 		const dependencies = new Map();
 
 		const response = await server.respond(new Request(config.prerender.origin + encoded), {
-			getClientAddress,
+			getClientAddress() {
+				throw new Error('Cannot read clientAddress during prerendering');
+			},
 			prerendering: {
 				dependencies
+			},
+			read: (file) => {
+				// stuff we just wrote
+				const filepath = saved.get(file);
+				if (filepath) return readFileSync(filepath);
+
+				// stuff in `static`
+				return readFileSync(join(config.files.assets, file));
 			}
 		});
 
@@ -367,58 +350,6 @@ export async function prerender() {
 		saved.set(file, dest);
 	}
 
-	for (const route of manifest._.routes) {
-		if (route.endpoint) {
-			const mod = await route.endpoint();
-			if (mod.prerender !== undefined) {
-				validate_server_exports(mod, route.id);
-
-				if (mod.prerender && (mod.POST || mod.PATCH || mod.PUT || mod.DELETE)) {
-					throw new Error(
-						`Cannot prerender a +server file with POST, PATCH, PUT, or DELETE (${route.id})`
-					);
-				}
-
-				prerender_map.set(route.id, mod.prerender);
-			}
-		}
-
-		if (route.page) {
-			const nodes = await Promise.all(
-				[...route.page.layouts, route.page.leaf].map((n) => {
-					if (n !== undefined) return manifest._.nodes[n]();
-				})
-			);
-
-			const layouts = nodes.slice(0, -1);
-			const page = nodes.at(-1);
-
-			for (const layout of layouts) {
-				if (layout) {
-					validate_common_exports(layout.server, route.id);
-					validate_common_exports(layout.universal, route.id);
-				}
-			}
-
-			if (page) {
-				validate_page_server_exports(page.server, route.id);
-				validate_common_exports(page.universal, route.id);
-			}
-
-			const should_prerender = get_option(nodes, 'prerender');
-			const prerender =
-				should_prerender === true ||
-				// Try prerendering if ssr is false and no server needed. Set it to 'auto' so that
-				// the route is not removed from the manifest, there could be a server load function.
-				// People can opt out of this behavior by explicitly setting prerender to false
-				(should_prerender !== false && get_option(nodes, 'ssr') === false && !page?.server?.actions
-					? 'auto'
-					: should_prerender ?? false);
-
-			prerender_map.set(route.id, prerender);
-		}
-	}
-
 	for (const entry of config.prerender.entries) {
 		if (entry === '*') {
 			for (const [id, prerender] of prerender_map) {
@@ -467,10 +398,5 @@ export async function prerender() {
 		);
 	}
 
-	output_and_exit({ prerendered, prerender_map });
-}
-
-/** @return {string} */
-function getClientAddress() {
-	throw new Error('Cannot read clientAddress during prerendering');
+	return { prerendered, prerender_map };
 }

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

@@ -6,6 +6,7 @@ import { write_root } from './write_root.js';
 import { write_tsconfig } from './write_tsconfig.js';
 import { write_types, write_all_types } from './write_types/index.js';
 import { write_ambient } from './write_ambient.js';
+import { write_server } from './write_server.js';
 
 /**
  * Initialize SvelteKit's generated files.
@@ -27,6 +28,7 @@ export async function create(config) {
 	const output = path.join(config.kit.outDir, 'generated');
 
 	write_client_manifest(config, manifest_data, output);
+	write_server(config, output);
 	write_root(manifest_data, output);
 	write_matchers(manifest_data, output);
 	await write_all_types(config, manifest_data);
@@ -57,3 +59,11 @@ export async function all(config, mode) {
 	init(config, mode);
 	return await create(config);
 }
+
+/**
+ * Regenerate server-internal.js in response to src/{app.html,error.html,service-worker.js} changing
+ * @param {import('types').ValidatedConfig} config
+ */
+export function server(config) {
+	write_server(config, path.join(config.kit.outDir, 'generated'));
+}