From 06225673269201044358788f2a81dbe13912adce Mon Sep 17 00:00:00 2001
From: Martin Trapp <94928215+martrapp@users.noreply.github.com>
Date: Fri, 21 Jun 2024 06:58:18 +0200
Subject: [PATCH] Fall back to page reload when redirected to a cross origin
 URL (#11302)

* fall back to page reload when redirected to a cross origin URL

* Make redirect work with dynamically assigned ports

* undo
---
 .changeset/small-badgers-juggle.md            |  5 +++++
 .../view-transitions/src/pages/one.astro      |  1 +
 .../view-transitions/src/pages/redirect.astro | 10 ++++++++++
 packages/astro/e2e/view-transitions.test.js   | 20 +++++++++++++++++++
 packages/astro/src/transitions/router.ts      |  8 +++++++-
 5 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/small-badgers-juggle.md
 create mode 100644 packages/astro/e2e/fixtures/view-transitions/src/pages/redirect.astro

diff --git a/.changeset/small-badgers-juggle.md b/.changeset/small-badgers-juggle.md
new file mode 100644
index 0000000000..0f532fdfd1
--- /dev/null
+++ b/.changeset/small-badgers-juggle.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes an issue with the view transition router when redirecting to an URL with different origin.
diff --git a/packages/astro/e2e/fixtures/view-transitions/src/pages/one.astro b/packages/astro/e2e/fixtures/view-transitions/src/pages/one.astro
index 8e34eb5559..4f11cbbc0d 100644
--- a/packages/astro/e2e/fixtures/view-transitions/src/pages/one.astro
+++ b/packages/astro/e2e/fixtures/view-transitions/src/pages/one.astro
@@ -11,6 +11,7 @@ import Layout from '../components/Layout.astro';
 	<a id="click-self" href="">go to top</a>
 	<a id="click-redirect-two" href="/redirect-two">go to redirect 2</a>
 	<a id="click-redirect-external" href="/redirect-external">go to a redirect external</a>
+	<a id="click-redirect" href="/redirect">redirect cross-origin</a>
 	<a id="click-404" href="/undefined-page">go to undefined page</a>
 	<custom-a id="custom-click-two">
 		<template shadowrootmode="open">
diff --git a/packages/astro/e2e/fixtures/view-transitions/src/pages/redirect.astro b/packages/astro/e2e/fixtures/view-transitions/src/pages/redirect.astro
new file mode 100644
index 0000000000..7a356f46c0
--- /dev/null
+++ b/packages/astro/e2e/fixtures/view-transitions/src/pages/redirect.astro
@@ -0,0 +1,10 @@
+---
+const myURL = Astro.request.url;
+const redirectTo = (myURL.startsWith("http://localhost")
+? myURL.replace("http://localhost","http://127.0.0.1")
+: myURL.replace("http://127.0.0.1", "http://localhost"))
+.replace("redirect","two");
+return Astro.redirect(redirectTo);
+---
+
+<h1>Should not see this</h1>
diff --git a/packages/astro/e2e/view-transitions.test.js b/packages/astro/e2e/view-transitions.test.js
index e52c23ebaa..0af4cf2323 100644
--- a/packages/astro/e2e/view-transitions.test.js
+++ b/packages/astro/e2e/view-transitions.test.js
@@ -788,6 +788,26 @@ test.describe('View Transitions', () => {
 		expect(loads.length, 'There should be 2 page loads').toEqual(2);
 	});
 
+	test('Cross origin redirects do not raise errors', async ({ page, astro }) => {
+
+		let consoleErrors = [];
+		page.on('console', (msg) => {
+			if (msg.type() === 'error') {
+				consoleErrors.push(msg.text());
+			}
+		});
+		// Go to page 1
+		await page.goto(astro.resolveUrl('/one'));
+		let p = page.locator('#one');
+		await expect(p, 'should have content').toHaveText('Page 1');
+
+		await page.click('#click-redirect');
+		p = page.locator('#two');
+		await expect(p, 'should have content').toHaveText('Page 2');
+
+		expect(consoleErrors.length, 'There should be no errors').toEqual(0);
+	});
+
 	test('client:only styles are retained on transition (1/2)', async ({ page, astro }) => {
 		const totalExpectedStyles = 9;
 
diff --git a/packages/astro/src/transitions/router.ts b/packages/astro/src/transitions/router.ts
index faa6f9a4e0..0f3d912099 100644
--- a/packages/astro/src/transitions/router.ts
+++ b/packages/astro/src/transitions/router.ts
@@ -418,7 +418,13 @@ async function transition(
 		}
 		// if there was a redirection, show the final URL in the browser's address bar
 		if (response.redirected) {
-			preparationEvent.to = new URL(response.redirected);
+			const redirectedTo = new URL(response.redirected);
+			// but do not redirect cross origin
+			if (redirectedTo.origin !== preparationEvent.to.origin) {
+				preparationEvent.preventDefault();
+				return;
+			}
+			preparationEvent.to = redirectedTo;
 		}
 
 		parser ??= new DOMParser();