From 738e2d4f40a149670ba035402611c24413a9ca03 Mon Sep 17 00:00:00 2001
From: Jelmer Bot <jelmerbot@gmail.com>
Date: Wed, 8 May 2024 15:49:45 +0200
Subject: [PATCH 1/4] detect build-emitted assets in prerenderer

---
 .../kit/src/core/generate_manifest/index.js   |  9 ++++
 packages/kit/src/core/postbuild/prerender.js  |  5 +++
 packages/kit/src/exports/vite/index.js        |  1 +
 .../paths-base/custom_asset_plugin.js         | 41 +++++++++++++++++++
 .../src/routes/assets/emitted/+page.js        |  7 ++++
 .../src/routes/assets/emitted/+page.svelte    |  4 ++
 .../src/routes/assets/emitted/message.csv     |  1 +
 .../paths-base/test/tests.spec.js             |  5 +++
 .../prerendering/paths-base/vite.config.js    |  3 +-
 9 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
 create mode 100644 packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
 create mode 100644 packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
 create mode 100644 packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/message.csv

diff --git a/packages/kit/src/core/generate_manifest/index.js b/packages/kit/src/core/generate_manifest/index.js
index a2ef4cd4c619..2e63bc5c47a3 100644
--- a/packages/kit/src/core/generate_manifest/index.js
+++ b/packages/kit/src/core/generate_manifest/index.js
@@ -80,6 +80,15 @@ export function generate_manifest({ build_data, relative_path, routes }) {
 		mime_types[ext] ??= mime.lookup(ext) || '';
 	}
 
+	const emitted_asset_dir = path.resolve(build_data.out_dir, 'server', build_data.asset_prefix);
+	if (fs.existsSync(emitted_asset_dir)) {
+		for (const file of fs.readdirSync(emitted_asset_dir)) {
+			assets.push(path.join(build_data.asset_prefix, file).replaceAll(path.sep, '/'));
+			const ext = path.extname(file);
+			mime_types[ext] ??= mime.lookup(ext) || '';
+		}
+	}
+
 	// prettier-ignore
 	// String representation of
 	/** @template {import('@sveltejs/kit').SSRManifest} T */
diff --git a/packages/kit/src/core/postbuild/prerender.js b/packages/kit/src/core/postbuild/prerender.js
index 05c995ab9771..76394585a941 100644
--- a/packages/kit/src/core/postbuild/prerender.js
+++ b/packages/kit/src/core/postbuild/prerender.js
@@ -211,6 +211,11 @@ async function prerender({ out, manifest_path, metadata, verbose, env }) {
 				const filepath = saved.get(file);
 				if (filepath) return readFileSync(filepath);
 
+				// Static assets emitted during build
+				if (file.startsWith(config.appDir)) {
+					return readFileSync(join(config.outDir, 'output', 'server', file));
+				}
+
 				// stuff in `static`
 				return readFileSync(join(config.files.assets, file));
 			},
diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index c91055ba9aa7..4b19eda1492d 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -754,6 +754,7 @@ async function kit({ svelte_config }) {
 					app_path: `${kit.paths.base.slice(1)}${kit.paths.base ? '/' : ''}${kit.appDir}`,
 					manifest_data,
 					out_dir: out,
+					asset_prefix: vite_config.build.rollupOptions.output.assetFileNames.split('/[')[0],
 					service_worker: service_worker_entry_file ? 'service-worker.js' : null, // TODO make file configurable?
 					client: null,
 					server_manifest
diff --git a/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js b/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
new file mode 100644
index 000000000000..e39b7d094d3c
--- /dev/null
+++ b/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
@@ -0,0 +1,41 @@
+import fs from 'node:fs';
+import path from 'node:path';
+
+export default function () {
+	let config;
+	const ext = '.csv';
+	return {
+		name: 'vite-plugin-sveltekit-custom-asset',
+		resolveId(id) {
+			if (id.endsWith(ext)) {
+				return id;
+			}
+		},
+		configResolved(resolvedConfig) {
+			config = resolvedConfig;
+		},
+		load(id, options) {
+			if (!id.endsWith(ext)) return;
+			if (config.command === 'serve')
+				return `export default "${path.relative(process.cwd(), id).replaceAll(path.sep, '/')}";`;
+
+			const outName = config.build.rollupOptions.output.assetFileNames
+				.replace('[name]', path.basename(id, ext))
+				.replace('[hash]', '000000')
+				.replace('[extname]', ext);
+
+			if (config.build?.ssr) {
+				const ref = this.emitFile({
+					type: 'asset',
+					fileName: outName
+				});
+				fs.readFile(id, (err, data) => {
+					if (err) this.error(err);
+					this.setAssetSource(ref, data);
+				});
+			}
+
+			return `export default "${config.base}${outName}";`;
+		}
+	};
+}
diff --git a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
new file mode 100644
index 000000000000..ad8947e2176d
--- /dev/null
+++ b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
@@ -0,0 +1,7 @@
+import url from "./message.csv"
+
+export async function load({fetch}) {
+    const response = await fetch(url);
+    const asset = await response.text();
+    return { asset }
+}
\ No newline at end of file
diff --git a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
new file mode 100644
index 000000000000..ea472f490d29
--- /dev/null
+++ b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
@@ -0,0 +1,4 @@
+<script>
+    export let data;
+</script>
+<p>{data.asset}</p>
\ No newline at end of file
diff --git a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/message.csv b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/message.csv
new file mode 100644
index 000000000000..07beee08078d
--- /dev/null
+++ b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/message.csv
@@ -0,0 +1 @@
+A custom asset emitted by a vite plugin during build.
\ No newline at end of file
diff --git a/packages/kit/test/prerendering/paths-base/test/tests.spec.js b/packages/kit/test/prerendering/paths-base/test/tests.spec.js
index 77674df89c93..7ef974373ae1 100644
--- a/packages/kit/test/prerendering/paths-base/test/tests.spec.js
+++ b/packages/kit/test/prerendering/paths-base/test/tests.spec.js
@@ -29,3 +29,8 @@ test('prerenders /path-base/assets', () => {
 	const content = read('assets.html');
 	assert.match(content, /<img[^>]+src="\/path-base\//u);
 });
+
+test('prerenders /path-base/assets/emitted', () => {
+	const content = read('assets/emitted.html');
+	assert.ok(content.includes('<p>A custom asset emitted by a vite plugin during build.</p>'));
+});
\ No newline at end of file
diff --git a/packages/kit/test/prerendering/paths-base/vite.config.js b/packages/kit/test/prerendering/paths-base/vite.config.js
index 2857b2592d11..cd49ec622d63 100644
--- a/packages/kit/test/prerendering/paths-base/vite.config.js
+++ b/packages/kit/test/prerendering/paths-base/vite.config.js
@@ -1,5 +1,6 @@
 import * as path from 'node:path';
 import { sveltekit } from '@sveltejs/kit/vite';
+import csvasset from './custom_asset_plugin.js';
 
 /** @type {import('vite').UserConfig} */
 const config = {
@@ -13,7 +14,7 @@ const config = {
 
 	logLevel: 'silent',
 
-	plugins: [sveltekit()],
+	plugins: [csvasset(), sveltekit()],
 
 	server: {
 		fs: {

From a216d8c826d90bce18a0544efacbc9f3937d1756 Mon Sep 17 00:00:00 2001
From: Jelmer Bot <jelmerbot@gmail.com>
Date: Wed, 8 May 2024 16:24:48 +0200
Subject: [PATCH 2/4] lint and check fixes

---
 packages/kit/src/exports/vite/index.js              |  2 +-
 packages/kit/src/types/internal.d.ts                |  1 +
 .../prerendering/paths-base/custom_asset_plugin.js  |  2 +-
 .../paths-base/src/routes/assets/emitted/+page.js   | 13 +++++++------
 .../src/routes/assets/emitted/+page.svelte          |  5 +++--
 .../test/prerendering/paths-base/test/tests.spec.js |  2 +-
 packages/kit/types/index.d.ts                       |  1 +
 7 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 4b19eda1492d..393171283d0b 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -754,7 +754,7 @@ async function kit({ svelte_config }) {
 					app_path: `${kit.paths.base.slice(1)}${kit.paths.base ? '/' : ''}${kit.appDir}`,
 					manifest_data,
 					out_dir: out,
-					asset_prefix: vite_config.build.rollupOptions.output.assetFileNames.split('/[')[0],
+					asset_prefix: `${kit.appDir}/immutable/assets`,
 					service_worker: service_worker_entry_file ? 'service-worker.js' : null, // TODO make file configurable?
 					client: null,
 					server_manifest
diff --git a/packages/kit/src/types/internal.d.ts b/packages/kit/src/types/internal.d.ts
index af50cbe74c7d..38c6350c12c3 100644
--- a/packages/kit/src/types/internal.d.ts
+++ b/packages/kit/src/types/internal.d.ts
@@ -63,6 +63,7 @@ export interface BuildData {
 	app_path: string;
 	manifest_data: ManifestData;
 	out_dir: string;
+	asset_prefix: string;
 	service_worker: string | null;
 	client: {
 		start: string;
diff --git a/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js b/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
index e39b7d094d3c..3a28d6c3cabe 100644
--- a/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
+++ b/packages/kit/test/prerendering/paths-base/custom_asset_plugin.js
@@ -14,7 +14,7 @@ export default function () {
 		configResolved(resolvedConfig) {
 			config = resolvedConfig;
 		},
-		load(id, options) {
+		load(id) {
 			if (!id.endsWith(ext)) return;
 			if (config.command === 'serve')
 				return `export default "${path.relative(process.cwd(), id).replaceAll(path.sep, '/')}";`;
diff --git a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
index ad8947e2176d..ecd0785e6b06 100644
--- a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
+++ b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.js
@@ -1,7 +1,8 @@
-import url from "./message.csv"
+// @ts-ignore
+import url from './message.csv';
 
-export async function load({fetch}) {
-    const response = await fetch(url);
-    const asset = await response.text();
-    return { asset }
-}
\ No newline at end of file
+export async function load({ fetch }) {
+	const response = await fetch(url);
+	const asset = await response.text();
+	return { asset };
+}
diff --git a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
index ea472f490d29..33b39b7e03cd 100644
--- a/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
+++ b/packages/kit/test/prerendering/paths-base/src/routes/assets/emitted/+page.svelte
@@ -1,4 +1,5 @@
 <script>
-    export let data;
+	export let data;
 </script>
-<p>{data.asset}</p>
\ No newline at end of file
+
+<p>{data.asset}</p>
diff --git a/packages/kit/test/prerendering/paths-base/test/tests.spec.js b/packages/kit/test/prerendering/paths-base/test/tests.spec.js
index 7ef974373ae1..1ea39a737327 100644
--- a/packages/kit/test/prerendering/paths-base/test/tests.spec.js
+++ b/packages/kit/test/prerendering/paths-base/test/tests.spec.js
@@ -33,4 +33,4 @@ test('prerenders /path-base/assets', () => {
 test('prerenders /path-base/assets/emitted', () => {
 	const content = read('assets/emitted.html');
 	assert.ok(content.includes('<p>A custom asset emitted by a vite plugin during build.</p>'));
-});
\ No newline at end of file
+});
diff --git a/packages/kit/types/index.d.ts b/packages/kit/types/index.d.ts
index 1219176d5665..bb2a23166a95 100644
--- a/packages/kit/types/index.d.ts
+++ b/packages/kit/types/index.d.ts
@@ -1587,6 +1587,7 @@ declare module '@sveltejs/kit' {
 		app_path: string;
 		manifest_data: ManifestData;
 		out_dir: string;
+		asset_prefix: string;
 		service_worker: string | null;
 		client: {
 			start: string;

From 0fd65d309f029b36de41e28a3e8946d893e9385f Mon Sep 17 00:00:00 2001
From: Jelmer Bot <jelmerbot@gmail.com>
Date: Wed, 8 May 2024 16:31:41 +0200
Subject: [PATCH 3/4] add changeset

---
 .changeset/chilled-humans-roll.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/chilled-humans-roll.md

diff --git a/.changeset/chilled-humans-roll.md b/.changeset/chilled-humans-roll.md
new file mode 100644
index 000000000000..f9b97341116a
--- /dev/null
+++ b/.changeset/chilled-humans-roll.md
@@ -0,0 +1,5 @@
+---
+"@sveltejs/kit": patch
+---
+
+Detect assets emitted by vite plugins in prerenderer `fetch`.

From 59e62e6c3bb58c2e35c5df3416205246af18b3d4 Mon Sep 17 00:00:00 2001
From: Jelmer Bot <jelmerbot@gmail.com>
Date: Mon, 12 Aug 2024 12:45:30 +0200
Subject: [PATCH 4/4] Update .changeset/chilled-humans-roll.md

Co-authored-by: Tee Ming <chewteeming01@gmail.com>
---
 .changeset/chilled-humans-roll.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/chilled-humans-roll.md b/.changeset/chilled-humans-roll.md
index f9b97341116a..14e779a03a54 100644
--- a/.changeset/chilled-humans-roll.md
+++ b/.changeset/chilled-humans-roll.md
@@ -2,4 +2,4 @@
 "@sveltejs/kit": patch
 ---
 
-Detect assets emitted by vite plugins in prerenderer `fetch`.
+fix: detect assets emitted by vite plugins in prerenderer `fetch`.