From f4251a533ac3c82cc0128db1fa7a3d9747a6959c Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Tue, 10 Jun 2025 12:26:56 -0600
Subject: [PATCH 1/5] feat: Respect abort signals during serverside fetch
 optimization

---
 packages/kit/src/runtime/server/fetch.js      | 41 +++++++++++++++++--
 .../load/fetch-abort-signal/+page.server.js   | 31 ++++++++++++++
 .../load/fetch-abort-signal/+page.svelte      | 10 +++++
 .../load/fetch-abort-signal/data/+server.js   |  5 +++
 .../load/fetch-abort-signal/slow/+server.js   |  3 ++
 packages/kit/test/apps/basics/test/test.js    |  8 ++++
 6 files changed, 94 insertions(+), 4 deletions(-)
 create mode 100644 packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
 create mode 100644 packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
 create mode 100644 packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
 create mode 100644 packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js

diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index 913cedaf9748..99aa2a74cb8c 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -4,6 +4,42 @@ import * as paths from '__sveltekit/paths';
 import { read_implementation } from '__sveltekit/server';
 import { has_prerendered_path } from './utils.js';
 
+/**
+ * @param {Request} request
+ * @param {import('types').SSROptions} options
+ * @param {import('@sveltejs/kit').SSRManifest} manifest
+ * @param {import('types').SSRState} state
+ * @returns {Promise<Response>}
+ */
+async function internal_fetch(request, options, manifest, state) {
+	if (request.signal) {
+		if (request.signal.aborted) {
+			throw new DOMException('The operation was aborted.', 'AbortError');
+		}
+
+		/** @type {Promise<never>} */
+		const abortPromise = new Promise((_, reject) => {
+			const onAbort = () => {
+				reject(new DOMException('The operation was aborted.', 'AbortError'));
+			};
+			request.signal.addEventListener('abort', onAbort, { once: true });
+		});
+
+		return await Promise.race([
+			respond(request, options, manifest, {
+				...state,
+				depth: state.depth + 1
+			}),
+			abortPromise
+		]);
+	} else {
+		return await respond(request, options, manifest, {
+			...state,
+			depth: state.depth + 1
+		});
+	}
+}
+
 /**
  * @param {{
  *   event: import('@sveltejs/kit').RequestEvent;
@@ -145,10 +181,7 @@ export function create_fetch({ event, options, manifest, state, get_cookie_heade
 					);
 				}
 
-				const response = await respond(request, options, manifest, {
-					...state,
-					depth: state.depth + 1
-				});
+				const response = await internal_fetch(request, options, manifest, state);
 
 				const set_cookie = response.headers.get('set-cookie');
 				if (set_cookie) {
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
new file mode 100644
index 000000000000..448335f26eef
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
@@ -0,0 +1,31 @@
+export async function load({ fetch }) {
+	const abortedController = new AbortController();
+	abortedController.abort();
+	
+	let abortedImmediately = false;
+	try {
+		await fetch('/load/fetch-abort-signal/data', { signal: abortedController.signal });
+	} catch (error) {
+		if (error.name === 'AbortError') {
+			abortedImmediately = true;
+		}
+	}
+	
+	let abortedDuringRequest = false;
+	try {
+		await fetch('/load/fetch-abort-signal/slow', { signal: AbortSignal.timeout(100) });
+	} catch (error) {
+		if (error.name === 'AbortError') {
+			abortedDuringRequest = true;
+		}
+	}
+	
+	const successfulResponse = await fetch('/load/fetch-abort-signal/data');
+	const successfulData = await successfulResponse.json();
+	
+	return {
+		abortedImmediately,
+		abortedDuringRequest,
+		successfulData
+	};
+} 
\ No newline at end of file
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
new file mode 100644
index 000000000000..41d20e199602
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
@@ -0,0 +1,10 @@
+<script>
+	export let data;
+</script>
+
+<div>
+	<h1>AbortSignal Test Results</h1>
+	<p class="aborted-immediately">Aborted immediately: {data.abortedImmediately}</p>
+	<p class="aborted-during-request">Aborted during request: {data.abortedDuringRequest}</p>
+	<p class="successful-data">Successful data: {JSON.stringify(data.successfulData)}</p>
+</div>
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
new file mode 100644
index 000000000000..5eb037c64c43
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
@@ -0,0 +1,5 @@
+import { json } from '@sveltejs/kit';
+
+export async function GET() {
+	return json({ message: 'success', timestamp: Date.now() });
+} 
\ No newline at end of file
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js
new file mode 100644
index 000000000000..e67ca2baf9af
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js
@@ -0,0 +1,3 @@
+export function GET() {
+  return new Promise(() => {})
+} 
\ No newline at end of file
diff --git a/packages/kit/test/apps/basics/test/test.js b/packages/kit/test/apps/basics/test/test.js
index 5abb712141a1..caf81e0650c0 100644
--- a/packages/kit/test/apps/basics/test/test.js
+++ b/packages/kit/test/apps/basics/test/test.js
@@ -569,6 +569,14 @@ test.describe('Load', () => {
 
 		expect(await page.textContent('h1')).toBe('404');
 	});
+
+	test.only('AbortSignal works with internal fetch optimization', async ({ page }) => {
+		await page.goto('/load/fetch-abort-signal');
+
+		expect(await page.textContent('.aborted-immediately')).toBe('Aborted immediately: true');
+		expect(await page.textContent('.aborted-during-request')).toBe('Aborted during request: true');
+		expect(await page.textContent('.successful-data')).toContain('"message":"success"');
+	});
 });
 
 test.describe('Nested layouts', () => {

From 4ca2e17535af45294127b4f744b598659a3186b4 Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Tue, 10 Jun 2025 12:28:57 -0600
Subject: [PATCH 2/5] move

---
 packages/kit/src/runtime/server/fetch.js | 72 ++++++++++++------------
 1 file changed, 36 insertions(+), 36 deletions(-)

diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index 99aa2a74cb8c..1749d3f40abf 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -4,42 +4,6 @@ import * as paths from '__sveltekit/paths';
 import { read_implementation } from '__sveltekit/server';
 import { has_prerendered_path } from './utils.js';
 
-/**
- * @param {Request} request
- * @param {import('types').SSROptions} options
- * @param {import('@sveltejs/kit').SSRManifest} manifest
- * @param {import('types').SSRState} state
- * @returns {Promise<Response>}
- */
-async function internal_fetch(request, options, manifest, state) {
-	if (request.signal) {
-		if (request.signal.aborted) {
-			throw new DOMException('The operation was aborted.', 'AbortError');
-		}
-
-		/** @type {Promise<never>} */
-		const abortPromise = new Promise((_, reject) => {
-			const onAbort = () => {
-				reject(new DOMException('The operation was aborted.', 'AbortError'));
-			};
-			request.signal.addEventListener('abort', onAbort, { once: true });
-		});
-
-		return await Promise.race([
-			respond(request, options, manifest, {
-				...state,
-				depth: state.depth + 1
-			}),
-			abortPromise
-		]);
-	} else {
-		return await respond(request, options, manifest, {
-			...state,
-			depth: state.depth + 1
-		});
-	}
-}
-
 /**
  * @param {{
  *   event: import('@sveltejs/kit').RequestEvent;
@@ -228,3 +192,39 @@ function normalize_fetch_input(info, init, url) {
 
 	return new Request(typeof info === 'string' ? new URL(info, url) : info, init);
 }
+
+/**
+ * @param {Request} request
+ * @param {import('types').SSROptions} options
+ * @param {import('@sveltejs/kit').SSRManifest} manifest
+ * @param {import('types').SSRState} state
+ * @returns {Promise<Response>}
+ */
+async function internal_fetch(request, options, manifest, state) {
+	if (request.signal) {
+		if (request.signal.aborted) {
+			throw new DOMException('The operation was aborted.', 'AbortError');
+		}
+
+		/** @type {Promise<never>} */
+		const abortPromise = new Promise((_, reject) => {
+			const onAbort = () => {
+				reject(new DOMException('The operation was aborted.', 'AbortError'));
+			};
+			request.signal.addEventListener('abort', onAbort, { once: true });
+		});
+
+		return await Promise.race([
+			respond(request, options, manifest, {
+				...state,
+				depth: state.depth + 1
+			}),
+			abortPromise
+		]);
+	} else {
+		return await respond(request, options, manifest, {
+			...state,
+			depth: state.depth + 1
+		});
+	}
+}
\ No newline at end of file

From edd8be2def8dfd6d4d880a248e09182d344609f3 Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Tue, 10 Jun 2025 15:28:35 -0600
Subject: [PATCH 3/5] lint

---
 packages/kit/src/runtime/server/fetch.js               |  2 +-
 .../src/routes/load/fetch-abort-signal/+page.server.js | 10 +++++-----
 .../src/routes/load/fetch-abort-signal/data/+server.js |  2 +-
 .../src/routes/load/fetch-abort-signal/slow/+server.js |  4 ++--
 packages/kit/test/apps/basics/test/test.js             |  2 +-
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index 1749d3f40abf..ed68cc23d746 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -227,4 +227,4 @@ async function internal_fetch(request, options, manifest, state) {
 			depth: state.depth + 1
 		});
 	}
-}
\ No newline at end of file
+}
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
index 448335f26eef..a09839c974f2 100644
--- a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
@@ -1,7 +1,7 @@
 export async function load({ fetch }) {
 	const abortedController = new AbortController();
 	abortedController.abort();
-	
+
 	let abortedImmediately = false;
 	try {
 		await fetch('/load/fetch-abort-signal/data', { signal: abortedController.signal });
@@ -10,7 +10,7 @@ export async function load({ fetch }) {
 			abortedImmediately = true;
 		}
 	}
-	
+
 	let abortedDuringRequest = false;
 	try {
 		await fetch('/load/fetch-abort-signal/slow', { signal: AbortSignal.timeout(100) });
@@ -19,13 +19,13 @@ export async function load({ fetch }) {
 			abortedDuringRequest = true;
 		}
 	}
-	
+
 	const successfulResponse = await fetch('/load/fetch-abort-signal/data');
 	const successfulData = await successfulResponse.json();
-	
+
 	return {
 		abortedImmediately,
 		abortedDuringRequest,
 		successfulData
 	};
-} 
\ No newline at end of file
+}
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
index 5eb037c64c43..0c9615bc374e 100644
--- a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/data/+server.js
@@ -2,4 +2,4 @@ import { json } from '@sveltejs/kit';
 
 export async function GET() {
 	return json({ message: 'success', timestamp: Date.now() });
-} 
\ No newline at end of file
+}
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js
index e67ca2baf9af..633b106c0c0e 100644
--- a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/slow/+server.js
@@ -1,3 +1,3 @@
 export function GET() {
-  return new Promise(() => {})
-} 
\ No newline at end of file
+	return new Promise(() => {});
+}
diff --git a/packages/kit/test/apps/basics/test/test.js b/packages/kit/test/apps/basics/test/test.js
index caf81e0650c0..7f3bcf1910a1 100644
--- a/packages/kit/test/apps/basics/test/test.js
+++ b/packages/kit/test/apps/basics/test/test.js
@@ -570,7 +570,7 @@ test.describe('Load', () => {
 		expect(await page.textContent('h1')).toBe('404');
 	});
 
-	test.only('AbortSignal works with internal fetch optimization', async ({ page }) => {
+	test('AbortSignal works with internal fetch optimization', async ({ page }) => {
 		await page.goto('/load/fetch-abort-signal');
 
 		expect(await page.textContent('.aborted-immediately')).toBe('Aborted immediately: true');

From 53696bf833dbc9c1e33c8a80ffd03673e2751774 Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Wed, 11 Jun 2025 13:06:27 -0600
Subject: [PATCH 4/5] snake_case

---
 packages/kit/src/runtime/server/fetch.js      |  8 +++----
 .../load/fetch-abort-signal/+page.server.js   | 24 +++++++++----------
 .../load/fetch-abort-signal/+page.svelte      |  6 ++---
 3 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index ed68cc23d746..e58a84cbdf9d 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -207,11 +207,11 @@ async function internal_fetch(request, options, manifest, state) {
 		}
 
 		/** @type {Promise<never>} */
-		const abortPromise = new Promise((_, reject) => {
-			const onAbort = () => {
+		const abort_promise = new Promise((_, reject) => {
+			const on_abort = () => {
 				reject(new DOMException('The operation was aborted.', 'AbortError'));
 			};
-			request.signal.addEventListener('abort', onAbort, { once: true });
+			request.signal.addEventListener('abort', on_abort, { once: true });
 		});
 
 		return await Promise.race([
@@ -219,7 +219,7 @@ async function internal_fetch(request, options, manifest, state) {
 				...state,
 				depth: state.depth + 1
 			}),
-			abortPromise
+			abort_promise
 		]);
 	} else {
 		return await respond(request, options, manifest, {
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
index a09839c974f2..6cf4493e9ad6 100644
--- a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.server.js
@@ -1,31 +1,31 @@
 export async function load({ fetch }) {
-	const abortedController = new AbortController();
-	abortedController.abort();
+	const aborted_controller = new AbortController();
+	aborted_controller.abort();
 
-	let abortedImmediately = false;
+	let aborted_immediately = false;
 	try {
-		await fetch('/load/fetch-abort-signal/data', { signal: abortedController.signal });
+		await fetch('/load/fetch-abort-signal/data', { signal: aborted_controller.signal });
 	} catch (error) {
 		if (error.name === 'AbortError') {
-			abortedImmediately = true;
+			aborted_immediately = true;
 		}
 	}
 
-	let abortedDuringRequest = false;
+	let aborted_during_request = false;
 	try {
 		await fetch('/load/fetch-abort-signal/slow', { signal: AbortSignal.timeout(100) });
 	} catch (error) {
 		if (error.name === 'AbortError') {
-			abortedDuringRequest = true;
+			aborted_during_request = true;
 		}
 	}
 
-	const successfulResponse = await fetch('/load/fetch-abort-signal/data');
-	const successfulData = await successfulResponse.json();
+	const successful_response = await fetch('/load/fetch-abort-signal/data');
+	const successful_data = await successful_response.json();
 
 	return {
-		abortedImmediately,
-		abortedDuringRequest,
-		successfulData
+		aborted_immediately,
+		aborted_during_request,
+		successful_data
 	};
 }
diff --git a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
index 41d20e199602..1867db965604 100644
--- a/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
+++ b/packages/kit/test/apps/basics/src/routes/load/fetch-abort-signal/+page.svelte
@@ -4,7 +4,7 @@
 
 <div>
 	<h1>AbortSignal Test Results</h1>
-	<p class="aborted-immediately">Aborted immediately: {data.abortedImmediately}</p>
-	<p class="aborted-during-request">Aborted during request: {data.abortedDuringRequest}</p>
-	<p class="successful-data">Successful data: {JSON.stringify(data.successfulData)}</p>
+	<p class="aborted-immediately">Aborted immediately: {data.aborted_immediately}</p>
+	<p class="aborted-during-request">Aborted during request: {data.aborted_during_request}</p>
+	<p class="successful-data">Successful data: {JSON.stringify(data.successful_data)}</p>
 </div>

From d1699971151666f8f8f65310a7b49af906951ba8 Mon Sep 17 00:00:00 2001
From: "S. Elliott Johnson" <sejohnson@torchcloudconsulting.com>
Date: Wed, 11 Jun 2025 15:17:39 -0600
Subject: [PATCH 5/5] chore: Remove abort listener

---
 packages/kit/src/runtime/server/fetch.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/kit/src/runtime/server/fetch.js b/packages/kit/src/runtime/server/fetch.js
index e58a84cbdf9d..7403407a9477 100644
--- a/packages/kit/src/runtime/server/fetch.js
+++ b/packages/kit/src/runtime/server/fetch.js
@@ -206,21 +206,25 @@ async function internal_fetch(request, options, manifest, state) {
 			throw new DOMException('The operation was aborted.', 'AbortError');
 		}
 
+		let remove_abort_listener = () => {};
 		/** @type {Promise<never>} */
 		const abort_promise = new Promise((_, reject) => {
 			const on_abort = () => {
 				reject(new DOMException('The operation was aborted.', 'AbortError'));
 			};
 			request.signal.addEventListener('abort', on_abort, { once: true });
+			remove_abort_listener = () => request.signal.removeEventListener('abort', on_abort);
 		});
 
-		return await Promise.race([
+		const result = await Promise.race([
 			respond(request, options, manifest, {
 				...state,
 				depth: state.depth + 1
 			}),
 			abort_promise
 		]);
+		remove_abort_listener();
+		return result;
 	} else {
 		return await respond(request, options, manifest, {
 			...state,