run beforeNavigate callbacks after cancelled unloading navigation - closes #9170 (#9347)

Author: Rich-Harris

.changeset/gold-ways-repair.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: don't prevent `beforeNavigate` callbacks from running following a cancelled unloading navigation

packages/kit/src/runtime/client/client.js

@@ -1521,11 +1521,14 @@ export function create_client(app, target) {
 
 				// Ignore the following but fire beforeNavigate
 				if (external || options.reload) {
-					const navigation = before_navigate({ url, type: 'link' });
-					if (!navigation) {
+					if (before_navigate({ url, type: 'link' })) {
+						// set `navigating` to `true` to prevent `beforeNavigate` callbacks
+						// being called when the page unloads
+						navigating = true;
+					} else {
 						event.preventDefault();
 					}
-					navigating = true;
+
 					return;
 				}
 

packages/kit/test/apps/basics/src/routes/before-navigate/prevent-navigation/+page.svelte

@@ -17,6 +17,7 @@
 <h1>prevent navigation</h1>
 <a href="/before-navigate/a">a</a>
 <a href="/before-navigate/redirect">redirect</a>
+<a href="/before-navigate/prevent-navigation?x=1">self</a>
 <a href="https://google.com" target="_blank" rel="noreferrer">_blank</a>
 <a href="https://google.de">external</a>
 <pre>{times_triggered} {unload} {navigation_type}</pre>

packages/kit/test/apps/basics/test/cross-platform/client.test.js

@@ -200,6 +200,19 @@ test.describe('beforeNavigate', () => {
 		await page.goBack();
 		expect(await page.textContent('h1')).toBe('before_navigate_ran: false');
 	});
+
+	test('cancel() on an unloading navigation does not prevent subsequent beforeNavigate callbacks', async ({
+		page,
+		app
+	}) => {
+		await page.goto('/before-navigate/prevent-navigation');
+		await page.click('h1'); // The browsers block attempts to prevent navigation on a frame that's never had a user gesture.
+
+		await app.goto('https://google.de');
+		await app.goto('/before-navigate/prevent-navigation?x=1');
+
+		expect(await page.innerHTML('pre')).toBe('2 false goto');
+	});
 });
 
 test.describe('Scrolling', () => {