From 90749671b06b1d154fca47e726cced3cba3c95c6 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Thu, 27 May 2021 14:31:49 -0700
Subject: [PATCH 01/11] Passing the Rollup output options through to Vite

---
 packages/kit/src/core/build/index.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index 3137728009e7..70b3f2a83171 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -149,6 +149,9 @@ async function build_client({
 				...(user_config.build && user_config.build.rollupOptions),
 				input,
 				output: {
+					...(user_config.build &&
+						user_config.build.rollupOptions &&
+						user_config.build.rollupOptions.output),
 					entryFileNames: '[name]-[hash].js',
 					chunkFileNames: 'chunks/[name]-[hash].js',
 					assetFileNames: 'assets/[name]-[hash][extname]'

From d524b7596ca59730eed971ddfccfef0b6421c15c Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Sun, 30 May 2021 14:00:43 -0700
Subject: [PATCH 02/11] Added deep_merge

---
 packages/kit/src/core/utils.js      |  52 ++++++++++
 packages/kit/src/core/utils.spec.js | 152 ++++++++++++++++++++++++++++
 2 files changed, 204 insertions(+)
 create mode 100644 packages/kit/src/core/utils.spec.js

diff --git a/packages/kit/src/core/utils.js b/packages/kit/src/core/utils.js
index d80f38e89f9f..a26eefbdf395 100644
--- a/packages/kit/src/core/utils.js
+++ b/packages/kit/src/core/utils.js
@@ -106,3 +106,55 @@ function find_svelte_packages(cwd) {
 export function get_no_external(cwd, user_specified_deps = []) {
 	return [...user_specified_deps, ...find_svelte_packages(cwd)];
 }
+
+/**
+ * Merges b into a, recursively, mutating a.
+ * @param {Object} a
+ * @param {Object} b
+ * @param {string[]} path array of property names representing the current
+ *     location in the tree
+ */
+function merge_into(a, b, conflicts = [], path = []) {
+	const is_object = (x) => typeof x === 'object' && !Array.isArray(x);
+	for (const prop in b) {
+		if (is_object(b[prop])) {
+			if (!is_object(a[prop])) {
+				if (a[prop] !== undefined) {
+					conflicts.push([...path, prop].join('.'));
+				}
+				a[prop] = {};
+			}
+			merge_into(a[prop], b[prop], conflicts, [...path, prop]);
+		} else if (Array.isArray(b[prop])) {
+			if (!Array.isArray(a[prop])) {
+				if (a[prop] !== undefined) {
+					conflicts.push([...path, prop].join('.'));
+				}
+				a[prop] = [];
+			}
+			a[prop].push(...b[prop]);
+		} else {
+			if (a[prop] !== undefined) {
+				conflicts.push([...path, prop].join('.'));
+			}
+			a[prop] = b[prop];
+		}
+	}
+}
+
+/**
+ * Takes zero or more objects and returns a new object that has all the values
+ * deeply merged together. None of the original objects will be mutated at any
+ * level, and the returned object will have no references to the original
+ * objects at any depth. If there's a conflict the last one wins, except for
+ * arrays which will be combined.
+ * @param {...Object} objects
+ * @returns {[Object, string[]]} a 2-tuple with the merged object, and a list of
+ *     merge conflicts if there were any, in dotted notation
+ */
+export function deep_merge(...objects) {
+	const result = {};
+	const conflicts = [];
+	objects.forEach((o) => merge_into(result, o, conflicts));
+	return [result, conflicts];
+}
diff --git a/packages/kit/src/core/utils.spec.js b/packages/kit/src/core/utils.spec.js
new file mode 100644
index 000000000000..29366183fb3c
--- /dev/null
+++ b/packages/kit/src/core/utils.spec.js
@@ -0,0 +1,152 @@
+import { test, suite } from 'uvu';
+import * as assert from 'uvu/assert';
+import { deep_merge } from './utils.js';
+
+const deepMergeSuite = suite('deep_merge');
+
+deepMergeSuite('basic test no conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			version: 1,
+			animalSounds: {
+				cow: 'moo'
+			}
+		},
+		{
+			animalSounds: {
+				duck: 'quack'
+			},
+			locale: 'en_US'
+		}
+	);
+	assert.equal(merged, {
+		version: 1,
+		locale: 'en_US',
+		animalSounds: {
+			cow: 'moo',
+			duck: 'quack'
+		}
+	});
+	assert.equal(conflicts, []);
+});
+
+deepMergeSuite('three way merge no conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			animalSounds: {
+				cow: 'moo'
+			}
+		},
+		{
+			animalSounds: {
+				duck: 'quack'
+			}
+		},
+		{
+			animalSounds: {
+				dog: {
+					singular: 'bark',
+					plural: 'barks'
+				}
+			}
+		}
+	);
+	assert.equal(merged, {
+		animalSounds: {
+			cow: 'moo',
+			duck: 'quack',
+			dog: {
+				singular: 'bark',
+				plural: 'barks'
+			}
+		}
+	});
+	assert.equal(conflicts, []);
+});
+
+deepMergeSuite('merge with conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			person: {
+				firstName: 'John',
+				lastName: 'Doe',
+				address: {
+					line1: '123 Main St',
+					city: 'Seattle',
+					state: 'WA'
+				}
+			}
+		},
+		{
+			person: {
+				middleInitial: 'Q',
+				address: '123 Main St, Seattle, WA'
+			}
+		}
+	);
+	assert.equal(merged, {
+		person: {
+			firstName: 'John',
+			middleInitial: 'Q',
+			lastName: 'Doe',
+			address: '123 Main St, Seattle, WA'
+		}
+	});
+	assert.equal(conflicts, ['person.address']);
+});
+
+deepMergeSuite('merge with arrays', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			paths: ['/foo', '/bar']
+		},
+		{
+			paths: ['/alpha', '/beta']
+		}
+	);
+	assert.equal(merged, {
+		paths: ['/foo', '/bar', '/alpha', '/beta']
+	});
+});
+
+deepMergeSuite('empty', async () => {
+	const [merged, conflicts] = deep_merge();
+	assert.equal(merged, {});
+});
+
+deepMergeSuite('mutability safety', () => {
+	const input1 = {
+		person: {
+			firstName: 'John',
+			lastName: 'Doe',
+			address: {
+				line1: '123 Main St',
+				city: 'Seattle'
+			}
+		}
+	};
+	const input2 = {
+		person: {
+			middleInitial: 'L',
+			lastName: 'Smith',
+			address: {
+				state: 'WA'
+			}
+		}
+	};
+	const snapshot1 = JSON.stringify(input1);
+	const snapshot2 = JSON.stringify(input2);
+
+	const [merged, conflicts] = deep_merge(input1, input2);
+
+	// Mess with the result
+	merged.person.middleInitial = 'Z';
+	merged.person.address.zipCode = '98103';
+	merged.person = {};
+
+	// Make sure nothing in the inputs changed
+	assert.snapshot(snapshot1, JSON.stringify(input1));
+	assert.snapshot(snapshot2, JSON.stringify(input2));
+});
+
+deepMergeSuite.run();

From 628cf5958c2e2b1155bdda6ebcd9bacb7ee9efcf Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Sun, 30 May 2021 16:04:26 -0700
Subject: [PATCH 03/11] Using deep_merge in vite.build()

---
 packages/kit/src/core/build/index.js | 69 ++++++++++++++++++----------
 1 file changed, 44 insertions(+), 25 deletions(-)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index 70b3f2a83171..77826cc78b89 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -2,12 +2,13 @@ import fs from 'fs';
 import path from 'path';
 import { rimraf } from '../filesystem/index.js';
 import create_manifest_data from '../../core/create_manifest_data/index.js';
-import { copy_assets, get_no_external, posixify, resolve_entry } from '../utils.js';
+import { copy_assets, get_no_external, posixify, resolve_entry, deep_merge } from '../utils.js';
 import { create_app } from '../../core/create_app/index.js';
 import vite from 'vite';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import glob from 'tiny-glob/sync.js';
 import { SVELTE_KIT } from '../constants.js';
+import colors from 'kleur';
 
 /** @param {any} value */
 const s = (value) => JSON.stringify(value);
@@ -134,24 +135,19 @@ async function build_client({
 	/** @type {any} */
 	const user_config = config.kit.vite();
 
-	await vite.build({
-		...user_config,
+	/** @type {[any, string[]]} */
+	const [merged_config, conflicts] = deep_merge(user_config, {
 		configFile: false,
 		root: cwd,
 		base,
 		build: {
-			...user_config.build,
 			cssCodeSplit: true,
 			manifest: true,
 			outDir: client_out_dir,
 			polyfillDynamicImport: false,
 			rollupOptions: {
-				...(user_config.build && user_config.build.rollupOptions),
 				input,
 				output: {
-					...(user_config.build &&
-						user_config.build.rollupOptions &&
-						user_config.build.rollupOptions.output),
 					entryFileNames: '[name]-[hash].js',
 					chunkFileNames: 'chunks/[name]-[hash].js',
 					assetFileNames: 'assets/[name]-[hash][extname]'
@@ -160,15 +156,12 @@ async function build_client({
 			}
 		},
 		resolve: {
-			...user_config.resolve,
 			alias: {
-				...(user_config.resolve && user_config.resolve.alias),
 				$app: path.resolve(`${build_dir}/runtime/app`),
 				$lib: config.kit.files.lib
 			}
 		},
 		plugins: [
-			...(user_config.plugins || []),
 			svelte({
 				extensions: config.extensions,
 				emitCss: !config.kit.amp
@@ -176,6 +169,18 @@ async function build_client({
 		]
 	});
 
+	conflicts.forEach((conflict) => {
+		console.error(
+			colors
+				.bold()
+				.red(
+					`build_client: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+				)
+		);
+	});
+
+	await vite.build(merged_config);
+
 	/** @type {ClientManifest} */
 	const client_manifest = JSON.parse(fs.readFileSync(client_manifest_file, 'utf-8'));
 	fs.renameSync(client_manifest_file, `${output_dir}/manifest.json`); // inspectable but not shipped
@@ -398,19 +403,17 @@ async function build_server(
 	/** @type {any} */
 	const user_config = config.kit.vite();
 
-	await vite.build({
-		...user_config,
+	/** @type {[any, string[]]} */
+	const [merged_config, conflicts] = deep_merge(user_config, {
 		configFile: false,
 		root: cwd,
 		base,
 		build: {
 			target: 'es2018',
-			...user_config.build,
 			ssr: true,
 			outDir: `${output_dir}/server`,
 			polyfillDynamicImport: false,
 			rollupOptions: {
-				...(user_config.build && user_config.build.rollupOptions),
 				input: {
 					app: app_file
 				},
@@ -425,15 +428,12 @@ async function build_server(
 			}
 		},
 		resolve: {
-			...user_config.resolve,
 			alias: {
-				...(user_config.resolve && user_config.resolve.alias),
 				$app: path.resolve(`${build_dir}/runtime/app`),
 				$lib: config.kit.files.lib
 			}
 		},
 		plugins: [
-			...(user_config.plugins || []),
 			svelte({
 				extensions: config.extensions
 			})
@@ -443,7 +443,6 @@ async function build_server(
 		// so we need to ignore the fact that it's missing
 		// @ts-ignore
 		ssr: {
-			...user_config.ssr,
 			// note to self: this _might_ need to be ['svelte', '@sveltejs/kit', ...get_no_external()]
 			// but I'm honestly not sure. roll with this for now and see if it's ok
 			noExternal: get_no_external(cwd, user_config.ssr && user_config.ssr.noExternal)
@@ -452,6 +451,18 @@ async function build_server(
 			entries: []
 		}
 	});
+
+	conflicts.forEach((conflict) => {
+		console.error(
+			colors
+				.bold()
+				.red(
+					`build_server: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+				)
+		);
+	});
+
+	await vite.build(merged_config);
 }
 
 /**
@@ -507,20 +518,18 @@ async function build_service_worker(
 	/** @type {any} */
 	const user_config = config.kit.vite();
 
-	await vite.build({
-		...user_config,
+	/** @type {[any, string[]]} */
+	const [merged_config, conflicts] = deep_merge(user_config, {
 		configFile: false,
 		root: cwd,
 		base,
 		build: {
-			...user_config.build,
 			lib: {
 				entry: service_worker_entry_file,
 				name: 'app',
 				formats: ['es']
 			},
 			rollupOptions: {
-				...(user_config.build && user_config.build.rollupOptions),
 				output: {
 					entryFileNames: 'service-worker.js'
 				}
@@ -529,9 +538,7 @@ async function build_service_worker(
 			emptyOutDir: false
 		},
 		resolve: {
-			...user_config.resolve,
 			alias: {
-				...(user_config.resolve && user_config.resolve.alias),
 				'$service-worker': path.resolve(`${build_dir}/runtime/service-worker`)
 			}
 		},
@@ -539,6 +546,18 @@ async function build_service_worker(
 			entries: []
 		}
 	});
+
+	conflicts.forEach((conflict) => {
+		console.error(
+			colors
+				.bold()
+				.red(
+					`build_service_worker: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+				)
+		);
+	});
+
+	await vite.build(merged_config);
 }
 
 /** @param {string[]} array */

From e81c5e0d1f4b81e05ce2b0db200109af85286128 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Sun, 30 May 2021 21:27:13 -0700
Subject: [PATCH 04/11] Updated the error message formatting.

---
 packages/kit/src/core/build/index.js | 12 +++++++++---
 packages/kit/src/core/utils.js       |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index 77826cc78b89..9e27246815d1 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -174,7 +174,9 @@ async function build_client({
 			colors
 				.bold()
 				.red(
-					`build_client: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+					`build_client: The value for ${colors.italic(
+						`kit.vite.${conflict}`
+					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
 				)
 		);
 	});
@@ -457,7 +459,9 @@ async function build_server(
 			colors
 				.bold()
 				.red(
-					`build_server: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+					`build_server: The value for ${colors.italic(
+						`kit.vite.${conflict}`
+					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
 				)
 		);
 	});
@@ -552,7 +556,9 @@ async function build_service_worker(
 			colors
 				.bold()
 				.red(
-					`build_service_worker: The value for ${conflict} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
+					`build_service_worker: The value for ${colors.italic(
+						`kit.vite.${conflict}`
+					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
 				)
 		);
 	});
diff --git a/packages/kit/src/core/utils.js b/packages/kit/src/core/utils.js
index a26eefbdf395..6b7b95e7a2df 100644
--- a/packages/kit/src/core/utils.js
+++ b/packages/kit/src/core/utils.js
@@ -111,6 +111,7 @@ export function get_no_external(cwd, user_specified_deps = []) {
  * Merges b into a, recursively, mutating a.
  * @param {Object} a
  * @param {Object} b
+ * @param {string[]} conflicts array to accumulate conflicts in
  * @param {string[]} path array of property names representing the current
  *     location in the tree
  */

From 6f59e1d7e90dcb399d312feca3a3b5f2779537a3 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Sun, 30 May 2021 22:00:29 -0700
Subject: [PATCH 05/11] Forgot to lint

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

diff --git a/packages/kit/src/core/utils.spec.js b/packages/kit/src/core/utils.spec.js
index 29366183fb3c..dc400419ea58 100644
--- a/packages/kit/src/core/utils.spec.js
+++ b/packages/kit/src/core/utils.spec.js
@@ -1,4 +1,4 @@
-import { test, suite } from 'uvu';
+import { suite } from 'uvu';
 import * as assert from 'uvu/assert';
 import { deep_merge } from './utils.js';
 
@@ -96,7 +96,7 @@ deepMergeSuite('merge with conflicts', async () => {
 });
 
 deepMergeSuite('merge with arrays', async () => {
-	const [merged, conflicts] = deep_merge(
+	const [merged] = deep_merge(
 		{
 			paths: ['/foo', '/bar']
 		},
@@ -110,7 +110,7 @@ deepMergeSuite('merge with arrays', async () => {
 });
 
 deepMergeSuite('empty', async () => {
-	const [merged, conflicts] = deep_merge();
+	const [merged] = deep_merge();
 	assert.equal(merged, {});
 });
 
@@ -137,7 +137,7 @@ deepMergeSuite('mutability safety', () => {
 	const snapshot1 = JSON.stringify(input1);
 	const snapshot2 = JSON.stringify(input2);
 
-	const [merged, conflicts] = deep_merge(input1, input2);
+	const [merged] = deep_merge(input1, input2);
 
 	// Mess with the result
 	merged.person.middleInitial = 'Z';

From c803ce0911dee937196b0a97595033ece4366b31 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Thu, 3 Jun 2021 20:57:51 -0700
Subject: [PATCH 06/11] Updated copy in error message, and TS annotation to
 pass "pnpm check"

---
 packages/kit/src/core/build/index.js | 55 +++++++++++-----------------
 packages/kit/src/core/utils.js       | 13 +++++--
 2 files changed, 31 insertions(+), 37 deletions(-)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index 9e27246815d1..bb182cc3f6bc 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -78,6 +78,25 @@ export async function build(config, { cwd = process.cwd(), runtime = '@sveltejs/
 	};
 }
 
+/**
+ * @param {string?} scope used to prefix the error message
+ * @param {string[]} conflicts array of conflicts in dotted notation
+ */
+function print_vite_config_conflicts(scope, conflicts) {
+	const prefix = scope ? scope + ': ' : '';
+	conflicts.forEach((conflict) => {
+		console.error(
+			colors
+				.bold()
+				.red(
+					`${prefix}The value for ${colors.italic(
+						`kit.vite.${conflict}`
+					)} specified in svelte.config.js has been ignored. This is controlled by SvelteKit.`
+				)
+		);
+	});
+}
+
 /**
  * @param {{
  *   cwd: string;
@@ -169,17 +188,7 @@ async function build_client({
 		]
 	});
 
-	conflicts.forEach((conflict) => {
-		console.error(
-			colors
-				.bold()
-				.red(
-					`build_client: The value for ${colors.italic(
-						`kit.vite.${conflict}`
-					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
-				)
-		);
-	});
+	print_vite_config_conflicts('build_client', conflicts);
 
 	await vite.build(merged_config);
 
@@ -454,17 +463,7 @@ async function build_server(
 		}
 	});
 
-	conflicts.forEach((conflict) => {
-		console.error(
-			colors
-				.bold()
-				.red(
-					`build_server: The value for ${colors.italic(
-						`kit.vite.${conflict}`
-					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
-				)
-		);
-	});
+	print_vite_config_conflicts('build_server', conflicts);
 
 	await vite.build(merged_config);
 }
@@ -551,17 +550,7 @@ async function build_service_worker(
 		}
 	});
 
-	conflicts.forEach((conflict) => {
-		console.error(
-			colors
-				.bold()
-				.red(
-					`build_service_worker: The value for ${colors.italic(
-						`kit.vite.${conflict}`
-					)} specified in svelte.config.js has been ignored, as this is controlled by SvelteKit`
-				)
-		);
-	});
+	print_vite_config_conflicts('build_service_worker', conflicts);
 
 	await vite.build(merged_config);
 }
diff --git a/packages/kit/src/core/utils.js b/packages/kit/src/core/utils.js
index 6b7b95e7a2df..82c69e522e20 100644
--- a/packages/kit/src/core/utils.js
+++ b/packages/kit/src/core/utils.js
@@ -109,14 +109,18 @@ export function get_no_external(cwd, user_specified_deps = []) {
 
 /**
  * Merges b into a, recursively, mutating a.
- * @param {Object} a
- * @param {Object} b
+ * @param {Record<string, any>} a
+ * @param {Record<string, any>} b
  * @param {string[]} conflicts array to accumulate conflicts in
  * @param {string[]} path array of property names representing the current
  *     location in the tree
  */
 function merge_into(a, b, conflicts = [], path = []) {
+	/**
+	 * @param {any} x
+	 */
 	const is_object = (x) => typeof x === 'object' && !Array.isArray(x);
+
 	for (const prop in b) {
 		if (is_object(b[prop])) {
 			if (!is_object(a[prop])) {
@@ -150,11 +154,12 @@ function merge_into(a, b, conflicts = [], path = []) {
  * objects at any depth. If there's a conflict the last one wins, except for
  * arrays which will be combined.
  * @param {...Object} objects
- * @returns {[Object, string[]]} a 2-tuple with the merged object, and a list of
- *     merge conflicts if there were any, in dotted notation
+ * @returns {[Record<string, any>, string[]]} a 2-tuple with the merged object,
+ *     and a list of merge conflicts if there were any, in dotted notation
  */
 export function deep_merge(...objects) {
 	const result = {};
+	/** @type {string[]} */
 	const conflicts = [];
 	objects.forEach((o) => merge_into(result, o, conflicts));
 	return [result, conflicts];

From 7cc3e8dc538da87453cec901bf2fab39ebee0429 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Thu, 3 Jun 2021 21:03:04 -0700
Subject: [PATCH 07/11] Actual copy update.

---
 packages/kit/src/core/build/index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index bb182cc3f6bc..05ae7f7ea64c 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -91,7 +91,7 @@ function print_vite_config_conflicts(scope, conflicts) {
 				.red(
 					`${prefix}The value for ${colors.italic(
 						`kit.vite.${conflict}`
-					)} specified in svelte.config.js has been ignored. This is controlled by SvelteKit.`
+					)} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
 				)
 		);
 	});

From 1f2bab28f83a4222a3aa8a6c5d99545ecdc238ef Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Fri, 4 Jun 2021 20:51:57 -0700
Subject: [PATCH 08/11] Also using deep_merge in core/dev/index.js

---
 packages/kit/src/core/dev/index.js | 32 +++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/packages/kit/src/core/dev/index.js b/packages/kit/src/core/dev/index.js
index 349673bfe358..516cc2984ba8 100644
--- a/packages/kit/src/core/dev/index.js
+++ b/packages/kit/src/core/dev/index.js
@@ -11,7 +11,7 @@ import { create_app } from '../../core/create_app/index.js';
 import { rimraf } from '../filesystem/index.js';
 import { respond } from '../../runtime/server/index.js';
 import { getRawBody } from '../node/index.js';
-import { copy_assets, get_no_external, resolve_entry } from '../utils.js';
+import { copy_assets, get_no_external, resolve_entry, deep_merge } from '../utils.js';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import { get_server } from '../server/index.js';
 import '../../install-fetch.js';
@@ -79,23 +79,17 @@ class Watcher extends EventEmitter {
 		/** @type {any} */
 		const user_config = (this.config.kit.vite && this.config.kit.vite()) || {};
 
-		/**
-		 * @type {vite.ViteDevServer}
-		 */
-		this.vite = await vite.createServer({
-			...user_config,
+		/** @type {[any, string[]]} */
+		const [merged_config, conflicts] = deep_merge(user_config, {
 			configFile: false,
 			root: this.cwd,
 			resolve: {
-				...user_config.resolve,
 				alias: {
-					...(user_config.resolve && user_config.resolve.alias),
 					$app: path.resolve(`${this.dir}/runtime/app`),
 					$lib: this.config.kit.files.lib
 				}
 			},
 			plugins: [
-				...(user_config.plugins || []),
 				svelte({
 					extensions: this.config.extensions,
 					emitCss: !this.config.kit.amp
@@ -103,19 +97,33 @@ class Watcher extends EventEmitter {
 			],
 			publicDir: this.config.kit.files.assets,
 			server: {
-				...user_config.server,
 				middlewareMode: true
 			},
 			optimizeDeps: {
-				...user_config.optimizeDeps,
 				entries: []
 			},
 			ssr: {
-				...user_config.ssr,
 				noExternal: get_no_external(this.cwd, user_config.ssr && user_config.ssr.noExternal)
 			}
 		});
 
+		conflicts.forEach((conflict) => {
+			console.error(
+				colors
+					.bold()
+					.red(
+						`The value for ${colors.italic(
+							`kit.vite.${conflict}`
+						)} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
+					)
+			);
+		});
+
+		/**
+		 * @type {vite.ViteDevServer}
+		 */
+		this.vite = await vite.createServer(merged_config);
+
 		const validator = this.config.kit.amp && (await amp_validator.getInstance());
 
 		/**

From 7190b9b9648522ac475994cd823c7908a194c9b9 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Sat, 5 Jun 2021 11:00:20 -0700
Subject: [PATCH 09/11] Re-do of the core/dev/index.html changes on updated
 origin/master.

---
 packages/kit/src/core/dev/index.js | 33 ++++++++++++++++++------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/packages/kit/src/core/dev/index.js b/packages/kit/src/core/dev/index.js
index 9f3a92c9e55e..fc03c0d4119d 100644
--- a/packages/kit/src/core/dev/index.js
+++ b/packages/kit/src/core/dev/index.js
@@ -11,7 +11,7 @@ import { create_app } from '../../core/create_app/index.js';
 import { rimraf } from '../filesystem/index.js';
 import { respond } from '../../runtime/server/index.js';
 import { getRawBody } from '../node/index.js';
-import { copy_assets, get_no_external, resolve_entry } from '../utils.js';
+import { copy_assets, get_no_external, resolve_entry, deep_merge } from '../utils.js';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import { get_server } from '../server/index.js';
 import '../../install-fetch.js';
@@ -84,23 +84,17 @@ class Watcher extends EventEmitter {
 
 		this.server = await get_server(this.https, user_config, (req, res) => handler(req, res));
 
-		/**
-		 * @type {vite.ViteDevServer}
-		 */
-		this.vite = await vite.createServer({
-			...user_config,
+		/** @type {[any, string[]]} */
+		const [merged_config, conflicts] = deep_merge(user_config, {
 			configFile: false,
 			root: this.cwd,
 			resolve: {
-				...user_config.resolve,
 				alias: {
-					...(user_config.resolve && user_config.resolve.alias),
 					$app: path.resolve(`${this.dir}/runtime/app`),
 					$lib: this.config.kit.files.lib
 				}
 			},
 			plugins: [
-				...(user_config.plugins || []),
 				svelte({
 					extensions: this.config.extensions,
 					emitCss: !this.config.kit.amp
@@ -108,23 +102,36 @@ class Watcher extends EventEmitter {
 			],
 			publicDir: this.config.kit.files.assets,
 			server: {
-				...user_config.server,
 				middlewareMode: true,
 				hmr: {
-					...(user_config.server && user_config.server.hmr),
 					...(this.https ? { server: this.server, port: this.port } : {})
 				}
 			},
 			optimizeDeps: {
-				...user_config.optimizeDeps,
 				entries: []
 			},
 			ssr: {
-				...user_config.ssr,
 				noExternal: get_no_external(this.cwd, user_config.ssr && user_config.ssr.noExternal)
 			}
 		});
 
+		conflicts.forEach((conflict) => {
+			console.error(
+				colors
+					.bold()
+					.red(
+						`The value for ${colors.italic(
+							`kit.vite.${conflict}`
+						)} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
+					)
+			);
+		});
+
+		/**
+		 * @type {vite.ViteDevServer}
+		 */
+		this.vite = await vite.createServer(merged_config);
+
 		const validator = this.config.kit.amp && (await amp_validator.getInstance());
 
 		/**

From 8a86cd66fdbadaacc6d44762824cc5c270982d99 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Fri, 11 Jun 2021 14:29:43 -0700
Subject: [PATCH 10/11] Common print_config_conflicts function, that uses the
 logger.

---
 packages/kit/src/core/build/index.js | 35 +++++++++-------------------
 packages/kit/src/core/dev/index.js   | 20 +++++++---------
 packages/kit/src/core/utils.js       | 15 ++++++++++++
 3 files changed, 34 insertions(+), 36 deletions(-)

diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index 47f063e4258f..c0c157601dfb 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -2,13 +2,19 @@ import fs from 'fs';
 import path from 'path';
 import { rimraf } from '../filesystem/index.js';
 import create_manifest_data from '../../core/create_manifest_data/index.js';
-import { copy_assets, get_no_external, posixify, resolve_entry, deep_merge } from '../utils.js';
+import {
+	copy_assets,
+	get_no_external,
+	posixify,
+	resolve_entry,
+	deep_merge,
+	print_config_conflicts
+} from '../utils.js';
 import { create_app } from '../../core/create_app/index.js';
 import vite from 'vite';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import glob from 'tiny-glob/sync.js';
 import { SVELTE_KIT } from '../constants.js';
-import colors from 'kleur';
 
 /** @param {any} value */
 const s = (value) => JSON.stringify(value);
@@ -78,25 +84,6 @@ export async function build(config, { cwd = process.cwd(), runtime = '@sveltejs/
 	};
 }
 
-/**
- * @param {string?} scope used to prefix the error message
- * @param {string[]} conflicts array of conflicts in dotted notation
- */
-function print_vite_config_conflicts(scope, conflicts) {
-	const prefix = scope ? scope + ': ' : '';
-	conflicts.forEach((conflict) => {
-		console.error(
-			colors
-				.bold()
-				.red(
-					`${prefix}The value for ${colors.italic(
-						`kit.vite.${conflict}`
-					)} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
-				)
-		);
-	});
-}
-
 /**
  * @param {{
  *   cwd: string;
@@ -188,7 +175,7 @@ async function build_client({
 		]
 	});
 
-	print_vite_config_conflicts('build_client', conflicts);
+	print_config_conflicts(conflicts, 'kit.vite.', 'build_client');
 
 	await vite.build(merged_config);
 
@@ -463,7 +450,7 @@ async function build_server(
 		}
 	});
 
-	print_vite_config_conflicts('build_server', conflicts);
+	print_config_conflicts(conflicts, 'kit.vite.', 'build_server');
 
 	await vite.build(merged_config);
 }
@@ -550,7 +537,7 @@ async function build_service_worker(
 		}
 	});
 
-	print_vite_config_conflicts('build_service_worker', conflicts);
+	print_config_conflicts(conflicts, 'kit.vite.', 'build_service_worker');
 
 	await vite.build(merged_config);
 }
diff --git a/packages/kit/src/core/dev/index.js b/packages/kit/src/core/dev/index.js
index fc03c0d4119d..dd796f5ffb41 100644
--- a/packages/kit/src/core/dev/index.js
+++ b/packages/kit/src/core/dev/index.js
@@ -11,7 +11,13 @@ import { create_app } from '../../core/create_app/index.js';
 import { rimraf } from '../filesystem/index.js';
 import { respond } from '../../runtime/server/index.js';
 import { getRawBody } from '../node/index.js';
-import { copy_assets, get_no_external, resolve_entry, deep_merge } from '../utils.js';
+import {
+	copy_assets,
+	get_no_external,
+	resolve_entry,
+	deep_merge,
+	print_config_conflicts
+} from '../utils.js';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import { get_server } from '../server/index.js';
 import '../../install-fetch.js';
@@ -115,17 +121,7 @@ class Watcher extends EventEmitter {
 			}
 		});
 
-		conflicts.forEach((conflict) => {
-			console.error(
-				colors
-					.bold()
-					.red(
-						`The value for ${colors.italic(
-							`kit.vite.${conflict}`
-						)} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
-					)
-			);
-		});
+		print_config_conflicts(conflicts, 'kit.vite.');
 
 		/**
 		 * @type {vite.ViteDevServer}
diff --git a/packages/kit/src/core/utils.js b/packages/kit/src/core/utils.js
index 82c69e522e20..d1c121cdf9c5 100644
--- a/packages/kit/src/core/utils.js
+++ b/packages/kit/src/core/utils.js
@@ -164,3 +164,18 @@ export function deep_merge(...objects) {
 	objects.forEach((o) => merge_into(result, o, conflicts));
 	return [result, conflicts];
 }
+
+/**
+ * @param {string[]} conflicts - array of conflicts in dotted notation
+ * @param {string=} pathPrefix - prepended in front of the path
+ * @param {string=} scope - used to prefix the whole error message
+ */
+export function print_config_conflicts(conflicts, pathPrefix = '', scope) {
+	const prefix = scope ? scope + ': ' : '';
+	const log = logger({ verbose: false });
+	conflicts.forEach((conflict) => {
+		log.error(
+			`${prefix}The value for ${pathPrefix}${conflict} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
+		);
+	});
+}

From a11a64b95d688fddfb7ae13a57a9aaf4c8357662 Mon Sep 17 00:00:00 2001
From: John Simons <coolcucumber+github@gmail.com>
Date: Fri, 11 Jun 2021 15:25:39 -0700
Subject: [PATCH 11/11] Moved load_config => config

---
 packages/kit/src/cli.js                       |   2 +-
 packages/kit/src/core/build/index.js          |  10 +-
 .../src/core/{load_config => config}/index.js |  74 +++++++++
 .../{load_config => config}/index.spec.js     | 153 +++++++++++++++++-
 .../core/{load_config => config}/options.js   |   0
 .../test/fixtures/default-cjs/src/app.html    |   0
 .../fixtures/default-cjs/svelte.config.cjs    |   0
 .../test/fixtures/default-esm/src/app.html    |   0
 .../fixtures/default-esm/svelte.config.js     |   0
 .../{load_config => config}/test/index.js     |   0
 .../core/{load_config => config}/types.d.ts   |   0
 packages/kit/src/core/dev/index.js            |   9 +-
 packages/kit/src/core/utils.js                |  73 ---------
 packages/kit/src/core/utils.spec.js           | 152 -----------------
 packages/kit/test/test.js                     |   2 +-
 15 files changed, 231 insertions(+), 244 deletions(-)
 rename packages/kit/src/core/{load_config => config}/index.js (63%)
 rename packages/kit/src/core/{load_config => config}/index.spec.js (64%)
 rename packages/kit/src/core/{load_config => config}/options.js (100%)
 rename packages/kit/src/core/{load_config => config}/test/fixtures/default-cjs/src/app.html (100%)
 rename packages/kit/src/core/{load_config => config}/test/fixtures/default-cjs/svelte.config.cjs (100%)
 rename packages/kit/src/core/{load_config => config}/test/fixtures/default-esm/src/app.html (100%)
 rename packages/kit/src/core/{load_config => config}/test/fixtures/default-esm/svelte.config.js (100%)
 rename packages/kit/src/core/{load_config => config}/test/index.js (100%)
 rename packages/kit/src/core/{load_config => config}/types.d.ts (100%)
 delete mode 100644 packages/kit/src/core/utils.spec.js

diff --git a/packages/kit/src/cli.js b/packages/kit/src/cli.js
index f80e01a461b2..e09d9711a858 100644
--- a/packages/kit/src/cli.js
+++ b/packages/kit/src/cli.js
@@ -2,7 +2,7 @@ import { existsSync } from 'fs';
 import sade from 'sade';
 import colors from 'kleur';
 import * as ports from 'port-authority';
-import { load_config } from './core/load_config/index.js';
+import { load_config } from './core/config/index.js';
 import { networkInterfaces, release } from 'os';
 
 async function get_config() {
diff --git a/packages/kit/src/core/build/index.js b/packages/kit/src/core/build/index.js
index c0c157601dfb..43f2dd688228 100644
--- a/packages/kit/src/core/build/index.js
+++ b/packages/kit/src/core/build/index.js
@@ -2,14 +2,8 @@ import fs from 'fs';
 import path from 'path';
 import { rimraf } from '../filesystem/index.js';
 import create_manifest_data from '../../core/create_manifest_data/index.js';
-import {
-	copy_assets,
-	get_no_external,
-	posixify,
-	resolve_entry,
-	deep_merge,
-	print_config_conflicts
-} from '../utils.js';
+import { copy_assets, get_no_external, posixify, resolve_entry } from '../utils.js';
+import { deep_merge, print_config_conflicts } from '../config/index.js';
 import { create_app } from '../../core/create_app/index.js';
 import vite from 'vite';
 import svelte from '@sveltejs/vite-plugin-svelte';
diff --git a/packages/kit/src/core/load_config/index.js b/packages/kit/src/core/config/index.js
similarity index 63%
rename from packages/kit/src/core/load_config/index.js
rename to packages/kit/src/core/config/index.js
index 767304d9de1a..98465bb48032 100644
--- a/packages/kit/src/core/load_config/index.js
+++ b/packages/kit/src/core/config/index.js
@@ -2,6 +2,7 @@ import options from './options.js';
 import * as url from 'url';
 import path from 'path';
 import fs from 'fs';
+import { logger } from '../utils.js';
 
 /** @typedef {import('./types').ConfigDefinition} ConfigDefinition */
 
@@ -143,3 +144,76 @@ export function validate_config(config) {
 
 	return validated;
 }
+
+/**
+ * Merges b into a, recursively, mutating a.
+ * @param {Record<string, any>} a
+ * @param {Record<string, any>} b
+ * @param {string[]} conflicts array to accumulate conflicts in
+ * @param {string[]} path array of property names representing the current
+ *     location in the tree
+ */
+function merge_into(a, b, conflicts = [], path = []) {
+	/**
+	 * @param {any} x
+	 */
+	const is_object = (x) => typeof x === 'object' && !Array.isArray(x);
+
+	for (const prop in b) {
+		if (is_object(b[prop])) {
+			if (!is_object(a[prop])) {
+				if (a[prop] !== undefined) {
+					conflicts.push([...path, prop].join('.'));
+				}
+				a[prop] = {};
+			}
+			merge_into(a[prop], b[prop], conflicts, [...path, prop]);
+		} else if (Array.isArray(b[prop])) {
+			if (!Array.isArray(a[prop])) {
+				if (a[prop] !== undefined) {
+					conflicts.push([...path, prop].join('.'));
+				}
+				a[prop] = [];
+			}
+			a[prop].push(...b[prop]);
+		} else {
+			if (a[prop] !== undefined) {
+				conflicts.push([...path, prop].join('.'));
+			}
+			a[prop] = b[prop];
+		}
+	}
+}
+
+/**
+ * Takes zero or more objects and returns a new object that has all the values
+ * deeply merged together. None of the original objects will be mutated at any
+ * level, and the returned object will have no references to the original
+ * objects at any depth. If there's a conflict the last one wins, except for
+ * arrays which will be combined.
+ * @param {...Object} objects
+ * @returns {[Record<string, any>, string[]]} a 2-tuple with the merged object,
+ *     and a list of merge conflicts if there were any, in dotted notation
+ */
+export function deep_merge(...objects) {
+	const result = {};
+	/** @type {string[]} */
+	const conflicts = [];
+	objects.forEach((o) => merge_into(result, o, conflicts));
+	return [result, conflicts];
+}
+
+/**
+ * @param {string[]} conflicts - array of conflicts in dotted notation
+ * @param {string=} pathPrefix - prepended in front of the path
+ * @param {string=} scope - used to prefix the whole error message
+ */
+export function print_config_conflicts(conflicts, pathPrefix = '', scope) {
+	const prefix = scope ? scope + ': ' : '';
+	const log = logger({ verbose: false });
+	conflicts.forEach((conflict) => {
+		log.error(
+			`${prefix}The value for ${pathPrefix}${conflict} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
+		);
+	});
+}
diff --git a/packages/kit/src/core/load_config/index.spec.js b/packages/kit/src/core/config/index.spec.js
similarity index 64%
rename from packages/kit/src/core/load_config/index.spec.js
rename to packages/kit/src/core/config/index.spec.js
index d1138752f849..327952a6219f 100644
--- a/packages/kit/src/core/load_config/index.spec.js
+++ b/packages/kit/src/core/config/index.spec.js
@@ -1,6 +1,6 @@
-import { test } from 'uvu';
+import { test, suite } from 'uvu';
 import * as assert from 'uvu/assert';
-import { validate_config } from './index.js';
+import { validate_config, deep_merge } from './index.js';
 
 test('fills in defaults', () => {
 	const validated = validate_config({});
@@ -286,3 +286,152 @@ validate_paths(
 );
 
 test.run();
+
+const deepMergeSuite = suite('deep_merge');
+
+deepMergeSuite('basic test no conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			version: 1,
+			animalSounds: {
+				cow: 'moo'
+			}
+		},
+		{
+			animalSounds: {
+				duck: 'quack'
+			},
+			locale: 'en_US'
+		}
+	);
+	assert.equal(merged, {
+		version: 1,
+		locale: 'en_US',
+		animalSounds: {
+			cow: 'moo',
+			duck: 'quack'
+		}
+	});
+	assert.equal(conflicts, []);
+});
+
+deepMergeSuite('three way merge no conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			animalSounds: {
+				cow: 'moo'
+			}
+		},
+		{
+			animalSounds: {
+				duck: 'quack'
+			}
+		},
+		{
+			animalSounds: {
+				dog: {
+					singular: 'bark',
+					plural: 'barks'
+				}
+			}
+		}
+	);
+	assert.equal(merged, {
+		animalSounds: {
+			cow: 'moo',
+			duck: 'quack',
+			dog: {
+				singular: 'bark',
+				plural: 'barks'
+			}
+		}
+	});
+	assert.equal(conflicts, []);
+});
+
+deepMergeSuite('merge with conflicts', async () => {
+	const [merged, conflicts] = deep_merge(
+		{
+			person: {
+				firstName: 'John',
+				lastName: 'Doe',
+				address: {
+					line1: '123 Main St',
+					city: 'Seattle',
+					state: 'WA'
+				}
+			}
+		},
+		{
+			person: {
+				middleInitial: 'Q',
+				address: '123 Main St, Seattle, WA'
+			}
+		}
+	);
+	assert.equal(merged, {
+		person: {
+			firstName: 'John',
+			middleInitial: 'Q',
+			lastName: 'Doe',
+			address: '123 Main St, Seattle, WA'
+		}
+	});
+	assert.equal(conflicts, ['person.address']);
+});
+
+deepMergeSuite('merge with arrays', async () => {
+	const [merged] = deep_merge(
+		{
+			paths: ['/foo', '/bar']
+		},
+		{
+			paths: ['/alpha', '/beta']
+		}
+	);
+	assert.equal(merged, {
+		paths: ['/foo', '/bar', '/alpha', '/beta']
+	});
+});
+
+deepMergeSuite('empty', async () => {
+	const [merged] = deep_merge();
+	assert.equal(merged, {});
+});
+
+deepMergeSuite('mutability safety', () => {
+	const input1 = {
+		person: {
+			firstName: 'John',
+			lastName: 'Doe',
+			address: {
+				line1: '123 Main St',
+				city: 'Seattle'
+			}
+		}
+	};
+	const input2 = {
+		person: {
+			middleInitial: 'L',
+			lastName: 'Smith',
+			address: {
+				state: 'WA'
+			}
+		}
+	};
+	const snapshot1 = JSON.stringify(input1);
+	const snapshot2 = JSON.stringify(input2);
+
+	const [merged] = deep_merge(input1, input2);
+
+	// Mess with the result
+	merged.person.middleInitial = 'Z';
+	merged.person.address.zipCode = '98103';
+	merged.person = {};
+
+	// Make sure nothing in the inputs changed
+	assert.snapshot(snapshot1, JSON.stringify(input1));
+	assert.snapshot(snapshot2, JSON.stringify(input2));
+});
+
+deepMergeSuite.run();
diff --git a/packages/kit/src/core/load_config/options.js b/packages/kit/src/core/config/options.js
similarity index 100%
rename from packages/kit/src/core/load_config/options.js
rename to packages/kit/src/core/config/options.js
diff --git a/packages/kit/src/core/load_config/test/fixtures/default-cjs/src/app.html b/packages/kit/src/core/config/test/fixtures/default-cjs/src/app.html
similarity index 100%
rename from packages/kit/src/core/load_config/test/fixtures/default-cjs/src/app.html
rename to packages/kit/src/core/config/test/fixtures/default-cjs/src/app.html
diff --git a/packages/kit/src/core/load_config/test/fixtures/default-cjs/svelte.config.cjs b/packages/kit/src/core/config/test/fixtures/default-cjs/svelte.config.cjs
similarity index 100%
rename from packages/kit/src/core/load_config/test/fixtures/default-cjs/svelte.config.cjs
rename to packages/kit/src/core/config/test/fixtures/default-cjs/svelte.config.cjs
diff --git a/packages/kit/src/core/load_config/test/fixtures/default-esm/src/app.html b/packages/kit/src/core/config/test/fixtures/default-esm/src/app.html
similarity index 100%
rename from packages/kit/src/core/load_config/test/fixtures/default-esm/src/app.html
rename to packages/kit/src/core/config/test/fixtures/default-esm/src/app.html
diff --git a/packages/kit/src/core/load_config/test/fixtures/default-esm/svelte.config.js b/packages/kit/src/core/config/test/fixtures/default-esm/svelte.config.js
similarity index 100%
rename from packages/kit/src/core/load_config/test/fixtures/default-esm/svelte.config.js
rename to packages/kit/src/core/config/test/fixtures/default-esm/svelte.config.js
diff --git a/packages/kit/src/core/load_config/test/index.js b/packages/kit/src/core/config/test/index.js
similarity index 100%
rename from packages/kit/src/core/load_config/test/index.js
rename to packages/kit/src/core/config/test/index.js
diff --git a/packages/kit/src/core/load_config/types.d.ts b/packages/kit/src/core/config/types.d.ts
similarity index 100%
rename from packages/kit/src/core/load_config/types.d.ts
rename to packages/kit/src/core/config/types.d.ts
diff --git a/packages/kit/src/core/dev/index.js b/packages/kit/src/core/dev/index.js
index dd796f5ffb41..fdd51dd7eb25 100644
--- a/packages/kit/src/core/dev/index.js
+++ b/packages/kit/src/core/dev/index.js
@@ -11,13 +11,8 @@ import { create_app } from '../../core/create_app/index.js';
 import { rimraf } from '../filesystem/index.js';
 import { respond } from '../../runtime/server/index.js';
 import { getRawBody } from '../node/index.js';
-import {
-	copy_assets,
-	get_no_external,
-	resolve_entry,
-	deep_merge,
-	print_config_conflicts
-} from '../utils.js';
+import { copy_assets, get_no_external, resolve_entry } from '../utils.js';
+import { deep_merge, print_config_conflicts } from '../config/index.js';
 import svelte from '@sveltejs/vite-plugin-svelte';
 import { get_server } from '../server/index.js';
 import '../../install-fetch.js';
diff --git a/packages/kit/src/core/utils.js b/packages/kit/src/core/utils.js
index d1c121cdf9c5..d80f38e89f9f 100644
--- a/packages/kit/src/core/utils.js
+++ b/packages/kit/src/core/utils.js
@@ -106,76 +106,3 @@ function find_svelte_packages(cwd) {
 export function get_no_external(cwd, user_specified_deps = []) {
 	return [...user_specified_deps, ...find_svelte_packages(cwd)];
 }
-
-/**
- * Merges b into a, recursively, mutating a.
- * @param {Record<string, any>} a
- * @param {Record<string, any>} b
- * @param {string[]} conflicts array to accumulate conflicts in
- * @param {string[]} path array of property names representing the current
- *     location in the tree
- */
-function merge_into(a, b, conflicts = [], path = []) {
-	/**
-	 * @param {any} x
-	 */
-	const is_object = (x) => typeof x === 'object' && !Array.isArray(x);
-
-	for (const prop in b) {
-		if (is_object(b[prop])) {
-			if (!is_object(a[prop])) {
-				if (a[prop] !== undefined) {
-					conflicts.push([...path, prop].join('.'));
-				}
-				a[prop] = {};
-			}
-			merge_into(a[prop], b[prop], conflicts, [...path, prop]);
-		} else if (Array.isArray(b[prop])) {
-			if (!Array.isArray(a[prop])) {
-				if (a[prop] !== undefined) {
-					conflicts.push([...path, prop].join('.'));
-				}
-				a[prop] = [];
-			}
-			a[prop].push(...b[prop]);
-		} else {
-			if (a[prop] !== undefined) {
-				conflicts.push([...path, prop].join('.'));
-			}
-			a[prop] = b[prop];
-		}
-	}
-}
-
-/**
- * Takes zero or more objects and returns a new object that has all the values
- * deeply merged together. None of the original objects will be mutated at any
- * level, and the returned object will have no references to the original
- * objects at any depth. If there's a conflict the last one wins, except for
- * arrays which will be combined.
- * @param {...Object} objects
- * @returns {[Record<string, any>, string[]]} a 2-tuple with the merged object,
- *     and a list of merge conflicts if there were any, in dotted notation
- */
-export function deep_merge(...objects) {
-	const result = {};
-	/** @type {string[]} */
-	const conflicts = [];
-	objects.forEach((o) => merge_into(result, o, conflicts));
-	return [result, conflicts];
-}
-
-/**
- * @param {string[]} conflicts - array of conflicts in dotted notation
- * @param {string=} pathPrefix - prepended in front of the path
- * @param {string=} scope - used to prefix the whole error message
- */
-export function print_config_conflicts(conflicts, pathPrefix = '', scope) {
-	const prefix = scope ? scope + ': ' : '';
-	const log = logger({ verbose: false });
-	conflicts.forEach((conflict) => {
-		log.error(
-			`${prefix}The value for ${pathPrefix}${conflict} specified in svelte.config.js has been ignored. This option is controlled by SvelteKit.`
-		);
-	});
-}
diff --git a/packages/kit/src/core/utils.spec.js b/packages/kit/src/core/utils.spec.js
deleted file mode 100644
index dc400419ea58..000000000000
--- a/packages/kit/src/core/utils.spec.js
+++ /dev/null
@@ -1,152 +0,0 @@
-import { suite } from 'uvu';
-import * as assert from 'uvu/assert';
-import { deep_merge } from './utils.js';
-
-const deepMergeSuite = suite('deep_merge');
-
-deepMergeSuite('basic test no conflicts', async () => {
-	const [merged, conflicts] = deep_merge(
-		{
-			version: 1,
-			animalSounds: {
-				cow: 'moo'
-			}
-		},
-		{
-			animalSounds: {
-				duck: 'quack'
-			},
-			locale: 'en_US'
-		}
-	);
-	assert.equal(merged, {
-		version: 1,
-		locale: 'en_US',
-		animalSounds: {
-			cow: 'moo',
-			duck: 'quack'
-		}
-	});
-	assert.equal(conflicts, []);
-});
-
-deepMergeSuite('three way merge no conflicts', async () => {
-	const [merged, conflicts] = deep_merge(
-		{
-			animalSounds: {
-				cow: 'moo'
-			}
-		},
-		{
-			animalSounds: {
-				duck: 'quack'
-			}
-		},
-		{
-			animalSounds: {
-				dog: {
-					singular: 'bark',
-					plural: 'barks'
-				}
-			}
-		}
-	);
-	assert.equal(merged, {
-		animalSounds: {
-			cow: 'moo',
-			duck: 'quack',
-			dog: {
-				singular: 'bark',
-				plural: 'barks'
-			}
-		}
-	});
-	assert.equal(conflicts, []);
-});
-
-deepMergeSuite('merge with conflicts', async () => {
-	const [merged, conflicts] = deep_merge(
-		{
-			person: {
-				firstName: 'John',
-				lastName: 'Doe',
-				address: {
-					line1: '123 Main St',
-					city: 'Seattle',
-					state: 'WA'
-				}
-			}
-		},
-		{
-			person: {
-				middleInitial: 'Q',
-				address: '123 Main St, Seattle, WA'
-			}
-		}
-	);
-	assert.equal(merged, {
-		person: {
-			firstName: 'John',
-			middleInitial: 'Q',
-			lastName: 'Doe',
-			address: '123 Main St, Seattle, WA'
-		}
-	});
-	assert.equal(conflicts, ['person.address']);
-});
-
-deepMergeSuite('merge with arrays', async () => {
-	const [merged] = deep_merge(
-		{
-			paths: ['/foo', '/bar']
-		},
-		{
-			paths: ['/alpha', '/beta']
-		}
-	);
-	assert.equal(merged, {
-		paths: ['/foo', '/bar', '/alpha', '/beta']
-	});
-});
-
-deepMergeSuite('empty', async () => {
-	const [merged] = deep_merge();
-	assert.equal(merged, {});
-});
-
-deepMergeSuite('mutability safety', () => {
-	const input1 = {
-		person: {
-			firstName: 'John',
-			lastName: 'Doe',
-			address: {
-				line1: '123 Main St',
-				city: 'Seattle'
-			}
-		}
-	};
-	const input2 = {
-		person: {
-			middleInitial: 'L',
-			lastName: 'Smith',
-			address: {
-				state: 'WA'
-			}
-		}
-	};
-	const snapshot1 = JSON.stringify(input1);
-	const snapshot2 = JSON.stringify(input2);
-
-	const [merged] = deep_merge(input1, input2);
-
-	// Mess with the result
-	merged.person.middleInitial = 'Z';
-	merged.person.address.zipCode = '98103';
-	merged.person = {};
-
-	// Make sure nothing in the inputs changed
-	assert.snapshot(snapshot1, JSON.stringify(input1));
-	assert.snapshot(snapshot2, JSON.stringify(input2));
-});
-
-deepMergeSuite.run();
diff --git a/packages/kit/test/test.js b/packages/kit/test/test.js
index 78c4a3ae62d8..b70cd5876d2e 100644
--- a/packages/kit/test/test.js
+++ b/packages/kit/test/test.js
@@ -6,7 +6,7 @@ import { chromium } from 'playwright-chromium';
 import { dev } from '../src/core/dev/index.js';
 import { build } from '../src/core/build/index.js';
 import { start } from '../src/core/start/index.js';
-import { load_config } from '../src/core/load_config/index.js';
+import { load_config } from '../src/core/config/index.js';
 import { fileURLToPath, pathToFileURL } from 'url';
 import { format } from 'util';