From 80c167c137cfc87b076137365aa5640cfce76fb2 Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Fri, 14 Jan 2022 09:59:13 +0100
Subject: [PATCH 1/6] convert redirect uri to URL

to prevent encoding the redirect url multiple times
---
 .../kit/src/core/adapt/prerender/prerender.js | 12 ++++++++++--
 .../.svelte-kit/output/server/app.js          | 19 +++++++++++++++++--
 .../build/redirect-url-encoding/index.html    |  1 +
 .../routes/redirect-url-encoding/index.svelte |  0
 packages/kit/src/core/adapt/test/index.js     | 18 +++++++++++++++---
 5 files changed, 43 insertions(+), 7 deletions(-)
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte

diff --git a/packages/kit/src/core/adapt/prerender/prerender.js b/packages/kit/src/core/adapt/prerender/prerender.js
index 5ffb1ac6dc07..e49e1bf739d7 100644
--- a/packages/kit/src/core/adapt/prerender/prerender.js
+++ b/packages/kit/src/core/adapt/prerender/prerender.js
@@ -167,8 +167,16 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 				if (location) {
 					mkdirp(dirname(file));
 
+					let url;
+					try {
+						url = new URL(location);
+					} catch (error) {
+						log.error(`'${location}' is not a valid URL`);
+						url = location;
+					}
+
 					log.warn(`${rendered.status} ${decoded_path} -> ${location}`);
-					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${encodeURI(location)}">`);
+					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${url.toString()}">`);
 
 					const resolved = resolve(path, location);
 					if (is_root_relative(resolved)) {
@@ -222,7 +230,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 			});
 
 			if (is_html && config.kit.prerender.crawl) {
-				for (const href of crawl(/** @type {string} */ (rendered.body))) {
+				for (const href of crawl(/** @type {string} */(rendered.body))) {
 					if (href.startsWith('data:')) continue;
 
 					const resolved = resolve(path, href);
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
index a59d5d30f0a5..8b1aef05bcdb 100644
--- a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
@@ -1,5 +1,20 @@
+function redirectResponse() {
+	const urlSearchParams = new URLSearchParams({ 'redirect': 'https://kit.svelte.dev/docs' })
+
+	const redirectTo = `https://my.server.com/?${urlSearchParams.toString()}`
+
+	return {
+		status: 302,
+		headers: {
+			location: redirectTo
+		}
+	}
+}
+
 export class App {
-	render() {
+	render({ url }) {
+		if (url === 'http://prerender/redirect-url-encoding') return redirectResponse()
+
 		return {
 			status: 200,
 			headers: {
@@ -10,4 +25,4 @@ export class App {
 	}
 }
 
-export function override() {}
+export function override() { }
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html
new file mode 100644
index 000000000000..f38b6b7013b4
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=https://my.server.com/?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte b/packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/packages/kit/src/core/adapt/test/index.js b/packages/kit/src/core/adapt/test/index.js
index 2c212dee5055..934a2621ebe8 100644
--- a/packages/kit/src/core/adapt/test/index.js
+++ b/packages/kit/src/core/adapt/test/index.js
@@ -1,4 +1,4 @@
-import { rmSync } from 'fs';
+import { readFileSync, rmSync } from 'fs';
 import { join } from 'path';
 import * as uvu from 'uvu';
 import * as assert from 'uvu/assert';
@@ -112,7 +112,7 @@ suite('prerender', async () => {
 		// @ts-expect-error
 		server: { chunks: [] },
 		static: [],
-		entries: ['/nested']
+		entries: ['/nested', '/redirect-url-encoding']
 	};
 
 	const builder = create_builder({
@@ -130,7 +130,19 @@ suite('prerender', async () => {
 		dest
 	});
 
-	assert.equal(glob('**', { cwd: prerendered_files }), glob('**', { cwd: dest }));
+	const expectedFiles = glob('**', { cwd: prerendered_files });
+	const actualFiles = glob('**', { cwd: dest });
+
+	// test if all files are present
+	assert.equal(expectedFiles, actualFiles);
+
+	// check each file if content is correct
+	for (const file of expectedFiles.filter(file => file.endsWith('.html'))) {
+		const expectedContent = readFileSync(join(prerendered_files, file));
+		const actualContent = readFileSync(join(dest, file));
+
+		assert.equal(actualContent.toString(), expectedContent.toString());
+	}
 
 	rmSync(dest, { recursive: true, force: true });
 });

From 817945d12fd0bf6df36bd72c5d568037050053e6 Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Fri, 14 Jan 2022 14:04:46 +0100
Subject: [PATCH 2/6] run prettier+eslint

---
 packages/kit/src/core/adapt/prerender/prerender.js     |  2 +-
 .../prerender/.svelte-kit/output/server/app.js         | 10 +++++-----
 packages/kit/src/core/adapt/test/index.js              |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/packages/kit/src/core/adapt/prerender/prerender.js b/packages/kit/src/core/adapt/prerender/prerender.js
index e49e1bf739d7..1850c954893d 100644
--- a/packages/kit/src/core/adapt/prerender/prerender.js
+++ b/packages/kit/src/core/adapt/prerender/prerender.js
@@ -230,7 +230,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 			});
 
 			if (is_html && config.kit.prerender.crawl) {
-				for (const href of crawl(/** @type {string} */(rendered.body))) {
+				for (const href of crawl(/** @type {string} */ (rendered.body))) {
 					if (href.startsWith('data:')) continue;
 
 					const resolved = resolve(path, href);
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
index 8b1aef05bcdb..cd9c972e42c8 100644
--- a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
@@ -1,19 +1,19 @@
 function redirectResponse() {
-	const urlSearchParams = new URLSearchParams({ 'redirect': 'https://kit.svelte.dev/docs' })
+	const urlSearchParams = new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' });
 
-	const redirectTo = `https://my.server.com/?${urlSearchParams.toString()}`
+	const redirectTo = `https://my.server.com/?${urlSearchParams.toString()}`;
 
 	return {
 		status: 302,
 		headers: {
 			location: redirectTo
 		}
-	}
+	};
 }
 
 export class App {
 	render({ url }) {
-		if (url === 'http://prerender/redirect-url-encoding') return redirectResponse()
+		if (url === 'http://prerender/redirect-url-encoding') return redirectResponse();
 
 		return {
 			status: 200,
@@ -25,4 +25,4 @@ export class App {
 	}
 }
 
-export function override() { }
+export function override() {}
diff --git a/packages/kit/src/core/adapt/test/index.js b/packages/kit/src/core/adapt/test/index.js
index 934a2621ebe8..96e891360699 100644
--- a/packages/kit/src/core/adapt/test/index.js
+++ b/packages/kit/src/core/adapt/test/index.js
@@ -137,7 +137,7 @@ suite('prerender', async () => {
 	assert.equal(expectedFiles, actualFiles);
 
 	// check each file if content is correct
-	for (const file of expectedFiles.filter(file => file.endsWith('.html'))) {
+	for (const file of expectedFiles.filter((file) => file.endsWith('.html'))) {
 		const expectedContent = readFileSync(join(prerendered_files, file));
 		const actualContent = readFileSync(join(dest, file));
 

From d9726986e4e908e329e2b66f2becc7975e71f65a Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Sun, 16 Jan 2022 10:58:17 +0100
Subject: [PATCH 3/6] take into account different url types

---
 .../kit/src/core/adapt/prerender/prerender.js | 42 +++++++++++++------
 .../.svelte-kit/output/server/app.js          | 22 +++++++---
 .../redirected/index.html}                    |  0
 .../absolute-url/encoding}/index.html         |  0
 .../absolute-url/no-encoding/index.html       |  1 +
 .../redirects/path-url/encoding/index.html    |  1 +
 .../redirects/path-url/no-encoding/index.html |  1 +
 .../relative-url/encoding/index.html          |  1 +
 .../relative-url/no-encoding/index.html       |  1 +
 .../routes/redirect-url-encoding/index.svelte |  0
 packages/kit/src/core/adapt/test/index.js     | 20 ++++++---
 11 files changed, 65 insertions(+), 24 deletions(-)
 rename packages/kit/src/core/adapt/test/fixtures/prerender/{src/routes/nested/index.svelte => build/redirected/index.html} (100%)
 rename packages/kit/src/core/adapt/test/fixtures/prerender/build/{redirect-url-encoding => redirects/absolute-url/encoding}/index.html (100%)
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/no-encoding/index.html
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/encoding/index.html
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/no-encoding/index.html
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/encoding/index.html
 create mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/no-encoding/index.html
 delete mode 100644 packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte

diff --git a/packages/kit/src/core/adapt/prerender/prerender.js b/packages/kit/src/core/adapt/prerender/prerender.js
index 1850c954893d..61aaa24367da 100644
--- a/packages/kit/src/core/adapt/prerender/prerender.js
+++ b/packages/kit/src/core/adapt/prerender/prerender.js
@@ -98,6 +98,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 
 	/**
 	 * @param {string} path
+	 * @returns string
 	 */
 	function normalize(path) {
 		if (config.kit.trailingSlash === 'always') {
@@ -109,6 +110,28 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 		return path;
 	}
 
+	/**
+	 * @param {string} path
+	 * @returns string
+	 */
+	function remove_query_string(path) {
+		return path.split('?')[0];
+	}
+
+
+	/** @type {(location: string) => string} */
+	function encode_location(location) {
+		const is_relative_url = location.startsWith('.') || location.startsWith('/');
+		if (is_relative_url) {
+
+			const protocol = 'http://';
+			return new URL(protocol + location).toString().substring(protocol.length);
+		}
+
+		return new URL(location).toString();
+	}
+
+
 	const q = queue(config.kit.prerender.concurrency);
 
 	/**
@@ -116,12 +139,13 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 	 * @param {string?} referrer
 	 */
 	function enqueue(decoded_path, referrer) {
-		const path = encodeURI(normalize(decoded_path));
+		const decoded_path_without_query_string = remove_query_string(decoded_path);
+		const path = encodeURI(normalize(decoded_path_without_query_string));
 
 		if (seen.has(path)) return;
 		seen.add(path);
 
-		return q.add(() => visit(path, decoded_path, referrer));
+		return q.add(() => visit(path, decoded_path_without_query_string, referrer));
 	}
 
 	/**
@@ -167,16 +191,10 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 				if (location) {
 					mkdirp(dirname(file));
 
-					let url;
-					try {
-						url = new URL(location);
-					} catch (error) {
-						log.error(`'${location}' is not a valid URL`);
-						url = location;
-					}
+					const encoded_location = encode_location(location);
 
 					log.warn(`${rendered.status} ${decoded_path} -> ${location}`);
-					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${url.toString()}">`);
+					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${encoded_location}">`);
 
 					const resolved = resolve(path, location);
 					if (is_root_relative(resolved)) {
@@ -214,7 +232,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 
 				if (result.body) {
 					writeFileSync(file, result.body);
-					paths.push(dependency_path);
+					paths.push(normalize(dependency_path));
 				}
 
 				if (response_type === OK) {
@@ -230,7 +248,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 			});
 
 			if (is_html && config.kit.prerender.crawl) {
-				for (const href of crawl(/** @type {string} */ (rendered.body))) {
+				for (const href of crawl(/** @type {string} */(rendered.body))) {
 					if (href.startsWith('data:')) continue;
 
 					const resolved = resolve(path, href);
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
index cd9c972e42c8..ae2dce48556f 100644
--- a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
@@ -1,19 +1,29 @@
-function redirectResponse() {
-	const urlSearchParams = new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' });
+function get_redirect_response(url) {
+	const [, , , , url_type, encoding_style] = url.split('/')
 
-	const redirectTo = `https://my.server.com/?${urlSearchParams.toString()}`;
+	const base_url = (() => {
+		switch (url_type) {
+			case 'absolute-url': return 'https://my.server.com/';
+			case 'path-url': return './../../redirected';
+			case 'relative-url': return '/redirected';
+		}
+	})()
+
+	const search_params = encoding_style === 'encoding'
+		? new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' }).toString()
+		: 'redirect=https://kit.svelte.dev/docs';
 
 	return {
 		status: 302,
 		headers: {
-			location: redirectTo
+			location: `${base_url}?${search_params}`
 		}
 	};
 }
 
 export class App {
 	render({ url }) {
-		if (url === 'http://prerender/redirect-url-encoding') return redirectResponse();
+		if (url.startsWith('http://prerender/redirects/')) return get_redirect_response(url)
 
 		return {
 			status: 200,
@@ -25,4 +35,4 @@ export class App {
 	}
 }
 
-export function override() {}
+export function override() { }
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/nested/index.svelte b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirected/index.html
similarity index 100%
rename from packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/nested/index.svelte
rename to packages/kit/src/core/adapt/test/fixtures/prerender/build/redirected/index.html
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/encoding/index.html
similarity index 100%
rename from packages/kit/src/core/adapt/test/fixtures/prerender/build/redirect-url-encoding/index.html
rename to packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/encoding/index.html
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/no-encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/no-encoding/index.html
new file mode 100644
index 000000000000..1a5bb3d25abb
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/no-encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=https://my.server.com/?redirect=https://kit.svelte.dev/docs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/encoding/index.html
new file mode 100644
index 000000000000..0dd022727b4d
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=./redirected?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/no-encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/no-encoding/index.html
new file mode 100644
index 000000000000..24d828054c0a
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/no-encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=./redirected?redirect=https://kit.svelte.dev/docs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/encoding/index.html
new file mode 100644
index 000000000000..a28bb0712d34
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=redirected/?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/no-encoding/index.html b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/no-encoding/index.html
new file mode 100644
index 000000000000..eb2591dc4bfe
--- /dev/null
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/no-encoding/index.html
@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=redirected/?redirect=https://kit.svelte.dev/docs">
\ No newline at end of file
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte b/packages/kit/src/core/adapt/test/fixtures/prerender/src/routes/redirect-url-encoding/index.svelte
deleted file mode 100644
index e69de29bb2d1..000000000000
diff --git a/packages/kit/src/core/adapt/test/index.js b/packages/kit/src/core/adapt/test/index.js
index 96e891360699..177b24e31792 100644
--- a/packages/kit/src/core/adapt/test/index.js
+++ b/packages/kit/src/core/adapt/test/index.js
@@ -11,7 +11,7 @@ const __filename = fileURLToPath(import.meta.url);
 const __dirname = join(__filename, '..');
 
 /** @param {string} _msg */
-const logger = (_msg) => {};
+const logger = (_msg) => { };
 
 /** @type {import('types/internal').Logger} */
 const log = Object.assign(logger, {
@@ -112,7 +112,15 @@ suite('prerender', async () => {
 		// @ts-expect-error
 		server: { chunks: [] },
 		static: [],
-		entries: ['/nested', '/redirect-url-encoding']
+		entries: [
+			'/nested',
+			'/redirects/absolute-url/no-encoding',
+			'/redirects/absolute-url/encoding',
+			'/redirects/path-url/no-encoding',
+			'/redirects/path-url/encoding',
+			'/redirects/relative-url/no-encoding',
+			'/redirects/relative-url/encoding'
+		]
 	};
 
 	const builder = create_builder({
@@ -134,14 +142,14 @@ suite('prerender', async () => {
 	const actualFiles = glob('**', { cwd: dest });
 
 	// test if all files are present
-	assert.equal(expectedFiles, actualFiles);
+	assert.equal(actualFiles, expectedFiles);
 
 	// check each file if content is correct
 	for (const file of expectedFiles.filter((file) => file.endsWith('.html'))) {
-		const expectedContent = readFileSync(join(prerendered_files, file));
-		const actualContent = readFileSync(join(dest, file));
+		const expected_content = readFileSync(join(prerendered_files, file));
+		const actual_content = readFileSync(join(dest, file));
 
-		assert.equal(actualContent.toString(), expectedContent.toString());
+		assert.equal(actual_content.toString(), expected_content.toString(), `content of '${file}' is not equal`);
 	}
 
 	rmSync(dest, { recursive: true, force: true });

From 296a3aeab0c3005baec318497566403fed635f4f Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Sun, 16 Jan 2022 11:15:03 +0100
Subject: [PATCH 4/6] fix lint issues

---
 .prettierrc                                   |  8 +++++++
 .../kit/src/core/adapt/prerender/prerender.js |  5 +---
 .../.svelte-kit/output/server/app.js          | 24 +++++++++++--------
 packages/kit/src/core/adapt/test/index.js     |  8 +++++--
 4 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/.prettierrc b/.prettierrc
index 96f5919856ba..5c6c8539122e 100644
--- a/.prettierrc
+++ b/.prettierrc
@@ -21,6 +21,14 @@
 			"options": {
 				"requirePragma": true
 			}
+		},
+		{
+			"files": [
+				"packages/kit/src/core/adapt/test/fixtures/**/*.html"
+			],
+			"options": {
+				"requirePragma": true
+			}
 		}
 	]
 }
diff --git a/packages/kit/src/core/adapt/prerender/prerender.js b/packages/kit/src/core/adapt/prerender/prerender.js
index 61aaa24367da..52845fb60cf3 100644
--- a/packages/kit/src/core/adapt/prerender/prerender.js
+++ b/packages/kit/src/core/adapt/prerender/prerender.js
@@ -118,12 +118,10 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 		return path.split('?')[0];
 	}
 
-
 	/** @type {(location: string) => string} */
 	function encode_location(location) {
 		const is_relative_url = location.startsWith('.') || location.startsWith('/');
 		if (is_relative_url) {
-
 			const protocol = 'http://';
 			return new URL(protocol + location).toString().substring(protocol.length);
 		}
@@ -131,7 +129,6 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 		return new URL(location).toString();
 	}
 
-
 	const q = queue(config.kit.prerender.concurrency);
 
 	/**
@@ -248,7 +245,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 			});
 
 			if (is_html && config.kit.prerender.crawl) {
-				for (const href of crawl(/** @type {string} */(rendered.body))) {
+				for (const href of crawl(/** @type {string} */ (rendered.body))) {
 					if (href.startsWith('data:')) continue;
 
 					const resolved = resolve(path, href);
diff --git a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
index ae2dce48556f..73145fbfb36f 100644
--- a/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
+++ b/packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js
@@ -1,17 +1,21 @@
 function get_redirect_response(url) {
-	const [, , , , url_type, encoding_style] = url.split('/')
+	const [, , , , url_type, encoding_style] = url.split('/');
 
 	const base_url = (() => {
 		switch (url_type) {
-			case 'absolute-url': return 'https://my.server.com/';
-			case 'path-url': return './../../redirected';
-			case 'relative-url': return '/redirected';
+			case 'absolute-url':
+				return 'https://my.server.com/';
+			case 'path-url':
+				return './../../redirected';
+			case 'relative-url':
+				return '/redirected';
 		}
-	})()
+	})();
 
-	const search_params = encoding_style === 'encoding'
-		? new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' }).toString()
-		: 'redirect=https://kit.svelte.dev/docs';
+	const search_params =
+		encoding_style === 'encoding'
+			? new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' }).toString()
+			: 'redirect=https://kit.svelte.dev/docs';
 
 	return {
 		status: 302,
@@ -23,7 +27,7 @@ function get_redirect_response(url) {
 
 export class App {
 	render({ url }) {
-		if (url.startsWith('http://prerender/redirects/')) return get_redirect_response(url)
+		if (url.startsWith('http://prerender/redirects/')) return get_redirect_response(url);
 
 		return {
 			status: 200,
@@ -35,4 +39,4 @@ export class App {
 	}
 }
 
-export function override() { }
+export function override() {}
diff --git a/packages/kit/src/core/adapt/test/index.js b/packages/kit/src/core/adapt/test/index.js
index 177b24e31792..ff4d6b424dfb 100644
--- a/packages/kit/src/core/adapt/test/index.js
+++ b/packages/kit/src/core/adapt/test/index.js
@@ -11,7 +11,7 @@ const __filename = fileURLToPath(import.meta.url);
 const __dirname = join(__filename, '..');
 
 /** @param {string} _msg */
-const logger = (_msg) => { };
+const logger = (_msg) => {};
 
 /** @type {import('types/internal').Logger} */
 const log = Object.assign(logger, {
@@ -149,7 +149,11 @@ suite('prerender', async () => {
 		const expected_content = readFileSync(join(prerendered_files, file));
 		const actual_content = readFileSync(join(dest, file));
 
-		assert.equal(actual_content.toString(), expected_content.toString(), `content of '${file}' is not equal`);
+		assert.equal(
+			actual_content.toString(),
+			expected_content.toString(),
+			`content of '${file}' is not equal`
+		);
 	}
 
 	rmSync(dest, { recursive: true, force: true });

From 3a9fc7baf8bede5dcd04686e38c4f1ff5894973a Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Sun, 16 Jan 2022 11:20:04 +0100
Subject: [PATCH 5/6] rename to snake_case

---
 packages/kit/src/core/adapt/test/index.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/kit/src/core/adapt/test/index.js b/packages/kit/src/core/adapt/test/index.js
index ff4d6b424dfb..6b15b9df0ba1 100644
--- a/packages/kit/src/core/adapt/test/index.js
+++ b/packages/kit/src/core/adapt/test/index.js
@@ -138,14 +138,14 @@ suite('prerender', async () => {
 		dest
 	});
 
-	const expectedFiles = glob('**', { cwd: prerendered_files });
-	const actualFiles = glob('**', { cwd: dest });
+	const expected = glob('**', { cwd: prerendered_files });
+	const files = glob('**', { cwd: dest });
 
 	// test if all files are present
-	assert.equal(actualFiles, expectedFiles);
+	assert.equal(files, expected);
 
 	// check each file if content is correct
-	for (const file of expectedFiles.filter((file) => file.endsWith('.html'))) {
+	for (const file of expected.filter((file) => file.endsWith('.html'))) {
 		const expected_content = readFileSync(join(prerendered_files, file));
 		const actual_content = readFileSync(join(dest, file));
 

From d77e6a0a0462ae77408b43ffff88d7f5a0862781 Mon Sep 17 00:00:00 2001
From: Ivan Hofer <ivan.hofer@outlook.com>
Date: Sun, 16 Jan 2022 11:25:17 +0100
Subject: [PATCH 6/6] add changeset

---
 .changeset/green-rings-pump.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/green-rings-pump.md

diff --git a/.changeset/green-rings-pump.md b/.changeset/green-rings-pump.md
new file mode 100644
index 000000000000..a5c963bd4460
--- /dev/null
+++ b/.changeset/green-rings-pump.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[fix] don't encode redirects multiple times