From f6dc0046d970fbea0e77a70b9788d30facaf9da0 Mon Sep 17 00:00:00 2001
From: Matt Brophy <matt@brophy.org>
Date: Thu, 2 Feb 2023 11:26:44 -0500
Subject: [PATCH] Only check for differing origin on absolute URL redirects

---
 .changeset/thirty-frogs-wave.md |  5 +++++
 packages/router/router.ts       | 14 +++++++++-----
 2 files changed, 14 insertions(+), 5 deletions(-)
 create mode 100644 .changeset/thirty-frogs-wave.md

diff --git a/.changeset/thirty-frogs-wave.md b/.changeset/thirty-frogs-wave.md
new file mode 100644
index 0000000000..680abd5e68
--- /dev/null
+++ b/.changeset/thirty-frogs-wave.md
@@ -0,0 +1,5 @@
+---
+"@remix-run/router": patch
+---
+
+Only check for differing origin on absolute URL redirects
diff --git a/packages/router/router.ts b/packages/router/router.ts
index 1f56b629e1..6bdd3ef9b1 100644
--- a/packages/router/router.ts
+++ b/packages/router/router.ts
@@ -621,6 +621,8 @@ export const IDLE_BLOCKER: BlockerUnblocked = {
   location: undefined,
 };
 
+const ABSOLUTE_URL_REGEX = /^(?:[a-z][a-z0-9+.-]*:|\/\/)/i;
+
 const isBrowser =
   typeof window !== "undefined" &&
   typeof window.document !== "undefined" &&
@@ -1915,8 +1917,12 @@ export function createRouter(init: RouterInit): Router {
       "Expected a location on the redirect navigation"
     );
 
-    // Check if this an external redirect that goes to a new origin
-    if (isBrowser && typeof window?.location !== "undefined") {
+    // Check if this an absolute external redirect that goes to a new origin
+    if (
+      ABSOLUTE_URL_REGEX.test(redirect.location) &&
+      isBrowser &&
+      typeof window?.location !== "undefined"
+    ) {
       let newOrigin = init.history.createURL(redirect.location).origin;
       if (window.location.origin !== newOrigin) {
         if (replace) {
@@ -3093,10 +3099,8 @@ async function callLoaderOrAction(
         "Redirects returned/thrown from loaders/actions must have a Location header"
       );
 
-      let isAbsolute = /^(?:[a-z][a-z0-9+.-]*:|\/\/)/i.test(location);
-
       // Support relative routing in internal redirects
-      if (!isAbsolute) {
+      if (!ABSOLUTE_URL_REGEX.test(location)) {
         let activeMatches = matches.slice(0, matches.indexOf(match) + 1);
         let routePathnames = getPathContributingMatches(activeMatches).map(
           (match) => match.pathnameBase