From bcad8de2766451b11127a38fdb11b4d309e96951 Mon Sep 17 00:00:00 2001
From: Rich Harris <hello@rich-harris.dev>
Date: Mon, 9 Jan 2023 16:14:39 -0500
Subject: [PATCH 1/6] warn if comments are removed from HTML - closes #7493

---
 .changeset/cuddly-camels-hang.md              |  5 ++++
 packages/kit/src/exports/vite/build/utils.js  |  1 +
 packages/kit/src/exports/vite/dev/index.js    |  3 +++
 .../kit/src/runtime/server/page/render.js     | 23 +++++++++++++++----
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/cuddly-camels-hang.md

diff --git a/.changeset/cuddly-camels-hang.md b/.changeset/cuddly-camels-hang.md
new file mode 100644
index 000000000000..478598f3444d
--- /dev/null
+++ b/.changeset/cuddly-camels-hang.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Warn if comments are removed from HTML
diff --git a/packages/kit/src/exports/vite/build/utils.js b/packages/kit/src/exports/vite/build/utils.js
index c5bf6e4481c6..e930a208dcbf 100644
--- a/packages/kit/src/exports/vite/build/utils.js
+++ b/packages/kit/src/exports/vite/build/utils.js
@@ -127,6 +127,7 @@ export function get_build_setup_config({ config, ssr }) {
 			__SVELTEKIT_ADAPTER_NAME__: JSON.stringify(config.kit.adapter?.name),
 			__SVELTEKIT_APP_VERSION_FILE__: JSON.stringify(`${config.kit.appDir}/version.json`),
 			__SVELTEKIT_APP_VERSION_POLL_INTERVAL__: JSON.stringify(config.kit.version.pollInterval),
+			__SVELTEKIT_DEV__: false,
 			__SVELTEKIT_EMBEDDED__: config.kit.embedded ? 'true' : 'false'
 		},
 		resolve: {
diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index f1021713cdb1..4e401e33fc62 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -25,6 +25,9 @@ const cwd = process.cwd();
  * @return {Promise<Promise<() => void>>}
  */
 export async function dev(vite, vite_config, svelte_config) {
+	// @ts-expect-error
+	globalThis.__SVELTEKIT_DEV__ = true;
+
 	if (should_polyfill) {
 		installPolyfills();
 	}
diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index 030b435613f7..24438b690172 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -353,17 +353,32 @@ export async function render_response({
 	// add the content after the script/css links so the link elements are parsed first
 	head += rendered.head;
 
+	const html = options.app_template({
+		head,
+		body,
+		assets,
+		nonce: /** @type {string} */ (csp.nonce)
+	});
+
 	// TODO flush chunks as early as we can
-	const html =
+	const transformed =
 		(await resolve_opts.transformPageChunk({
-			html: options.app_template({ head, body, assets, nonce: /** @type {string} */ (csp.nonce) }),
+			html,
 			done: true
 		})) || '';
 
+	if (__SVELTEKIT_DEV__) {
+		if (transformed.split('<!--').length < html.split('<!--').length) {
+			console.warn(
+				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can have undesirable effects\u001B[39m\u001B[22m'
+			);
+		}
+	}
+
 	const headers = new Headers({
 		'x-sveltekit-page': 'true',
 		'content-type': 'text/html',
-		etag: `"${hash(html)}"`
+		etag: `"${hash(transformed)}"`
 	});
 
 	if (!state.prerendering) {
@@ -381,7 +396,7 @@ export async function render_response({
 		}
 	}
 
-	return new Response(html, {
+	return new Response(transformed, {
 		status,
 		headers
 	});

From 3de6e3a6c8a2f0956793b34361364bf750d3f5fc Mon Sep 17 00:00:00 2001
From: Rich Harris <hello@rich-harris.dev>
Date: Mon, 9 Jan 2023 17:41:25 -0500
Subject: [PATCH 2/6] use esm-env

---
 packages/kit/src/exports/vite/build/utils.js   | 1 -
 packages/kit/src/exports/vite/dev/index.js     | 3 ---
 packages/kit/src/runtime/server/page/render.js | 3 ++-
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/packages/kit/src/exports/vite/build/utils.js b/packages/kit/src/exports/vite/build/utils.js
index e930a208dcbf..c5bf6e4481c6 100644
--- a/packages/kit/src/exports/vite/build/utils.js
+++ b/packages/kit/src/exports/vite/build/utils.js
@@ -127,7 +127,6 @@ export function get_build_setup_config({ config, ssr }) {
 			__SVELTEKIT_ADAPTER_NAME__: JSON.stringify(config.kit.adapter?.name),
 			__SVELTEKIT_APP_VERSION_FILE__: JSON.stringify(`${config.kit.appDir}/version.json`),
 			__SVELTEKIT_APP_VERSION_POLL_INTERVAL__: JSON.stringify(config.kit.version.pollInterval),
-			__SVELTEKIT_DEV__: false,
 			__SVELTEKIT_EMBEDDED__: config.kit.embedded ? 'true' : 'false'
 		},
 		resolve: {
diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index 4e401e33fc62..f1021713cdb1 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -25,9 +25,6 @@ const cwd = process.cwd();
  * @return {Promise<Promise<() => void>>}
  */
 export async function dev(vite, vite_config, svelte_config) {
-	// @ts-expect-error
-	globalThis.__SVELTEKIT_DEV__ = true;
-
 	if (should_polyfill) {
 		installPolyfills();
 	}
diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index 24438b690172..0e22ddb56e8a 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -6,6 +6,7 @@ import { s } from '../../../utils/misc.js';
 import { Csp } from './csp.js';
 import { uneval_action_response } from './actions.js';
 import { clarify_devalue_error } from '../utils.js';
+import { DEV } from 'esm-env';
 
 // TODO rename this function/module
 
@@ -367,7 +368,7 @@ export async function render_response({
 			done: true
 		})) || '';
 
-	if (__SVELTEKIT_DEV__) {
+	if (DEV) {
 		if (transformed.split('<!--').length < html.split('<!--').length) {
 			console.warn(
 				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can have undesirable effects\u001B[39m\u001B[22m'

From d5659b95f8b69a7628433368d651c90a2ac4a64e Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Mon, 9 Jan 2023 17:42:44 -0500
Subject: [PATCH 3/6] Update packages/kit/src/runtime/server/page/render.js

---
 packages/kit/src/runtime/server/page/render.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index 0e22ddb56e8a..39928dd9bcdf 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -371,7 +371,7 @@ export async function render_response({
 	if (DEV) {
 		if (transformed.split('<!--').length < html.split('<!--').length) {
 			console.warn(
-				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can have undesirable effects\u001B[39m\u001B[22m'
+				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can break Svelte\'s hydration\u001B[39m\u001B[22m'
 			);
 		}
 	}

From a4d24398b2df4533cbb22c5e91c7327189b123ee Mon Sep 17 00:00:00 2001
From: Rich Harris <hello@rich-harris.dev>
Date: Mon, 9 Jan 2023 18:58:08 -0500
Subject: [PATCH 4/6] add explanatory comment

---
 packages/kit/src/runtime/server/page/render.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index 0e22ddb56e8a..923760852a7e 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -370,6 +370,8 @@ export async function render_response({
 
 	if (DEV) {
 		if (transformed.split('<!--').length < html.split('<!--').length) {
+			// the \u001B stuff is ANSI codes, so that we don't need to add a library to the runtime
+			// https://svelte.dev/repl/1b3f49696f0c44c881c34587f2537aa2
 			console.warn(
 				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can have undesirable effects\u001B[39m\u001B[22m'
 			);

From 90dc980c106eed0d7e7876da8e5ac173cd4bab2e Mon Sep 17 00:00:00 2001
From: Rich Harris <hello@rich-harris.dev>
Date: Mon, 9 Jan 2023 19:01:22 -0500
Subject: [PATCH 5/6] prettier

---
 packages/kit/src/runtime/server/page/render.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index d0e1de81539f..277d5fcea323 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -373,7 +373,7 @@ export async function render_response({
 			// the \u001B stuff is ANSI codes, so that we don't need to add a library to the runtime
 			// https://svelte.dev/repl/1b3f49696f0c44c881c34587f2537aa2
 			console.warn(
-				'\u001B[1m\u001B[31mRemoving comments in transformPageChunk can break Svelte\'s hydration\u001B[39m\u001B[22m'
+				"\u001B[1m\u001B[31mRemoving comments in transformPageChunk can break Svelte's hydration\u001B[39m\u001B[22m"
 			);
 		}
 	}

From cc4644a048d8be6185e7d45d829d2f632bd73125 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Tue, 10 Jan 2023 10:11:56 +0100
Subject: [PATCH 6/6] only warn if csr is true

---
 packages/kit/src/runtime/server/page/render.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index 277d5fcea323..851c1b04c4ca 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -368,7 +368,7 @@ export async function render_response({
 			done: true
 		})) || '';
 
-	if (DEV) {
+	if (DEV && page_config.csr) {
 		if (transformed.split('<!--').length < html.split('<!--').length) {
 			// the \u001B stuff is ANSI codes, so that we don't need to add a library to the runtime
 			// https://svelte.dev/repl/1b3f49696f0c44c881c34587f2537aa2