fix: Wrap route with location arg in location context (#9094)

* Wrap route with location arg in location context

In order for the `useLocation` hook to work with the use of the modal
pattern, routes with the locationArg prop are wrapped in a
LocationContext. This is done conditionally in order to ensure
performance in the default case doesn't change.

* Update useLocation unit tests

* Remove static markup from test for brevity

* Back out formatting change to test

Co-authored-by: John Pangalos <john@juni.co>
Co-authored-by: Matt Brophy <matt@brophy.org>

.changeset/hungry-vans-ring.md

@@ -0,0 +1,8 @@
+---
+"react-router": patch
+"react-router-dom": patch
+"react-router-dom-v5-compat": patch
+"react-router-native": patch
+---
+
+fix: update `useLocation` to return the scoped `Location` when inside a `<Routes location>` component

packages/react-router/__tests__/useLocation-test.tsx

@@ -2,9 +2,9 @@ import * as React from "react";
 import * as TestRenderer from "react-test-renderer";
 import { MemoryRouter, Routes, Route, useLocation } from "react-router";
 
-function ShowPath() {
-  let { pathname, search, hash } = useLocation();
-  return <pre>{JSON.stringify({ pathname, search, hash })}</pre>;
+function ShowLocation() {
+  let location = useLocation();
+  return <pre>{JSON.stringify(location)}</pre>;
 }
 
 describe("useLocation", () => {
@@ -14,16 +14,51 @@ describe("useLocation", () => {
       renderer = TestRenderer.create(
         <MemoryRouter initialEntries={["/home?the=search#the-hash"]}>
           <Routes>
-            <Route path="/home" element={<ShowPath />} />
+            <Route path="/home" element={<ShowLocation />} />
           </Routes>
         </MemoryRouter>
       );
     });
 
     expect(renderer.toJSON()).toMatchInlineSnapshot(`
       <pre>
-        {"pathname":"/home","search":"?the=search","hash":"#the-hash"}
+        {"pathname":"/home","search":"?the=search","hash":"#the-hash","state":null,"key":"default"}
       </pre>
     `);
   });
+
+  it("returns the scoped location object when nested in <Routes location>", () => {
+    let renderer: TestRenderer.ReactTestRenderer;
+    TestRenderer.act(() => {
+      renderer = TestRenderer.create(
+        <MemoryRouter initialEntries={["/home?the=search#the-hash"]}>
+          <App />
+        </MemoryRouter>
+      );
+    });
+
+    function App() {
+      return (
+        <div>
+          <Routes>
+            <Route path="/home" element={<ShowLocation />} />
+          </Routes>
+          <Routes location="/scoped?scoped=search#scoped-hash">
+            <Route path="/scoped" element={<ShowLocation />} />
+          </Routes>
+        </div>
+      );
+    }
+
+    expect(renderer.toJSON()).toMatchInlineSnapshot(`
+      <div>
+        <pre>
+          {"pathname":"/home","search":"?the=search","hash":"#the-hash","state":null,"key":"default"}
+        </pre>
+        <pre>
+          {"pathname":"/scoped","search":"?scoped=search","hash":"#scoped-hash","state":null,"key":"default"}
+        </pre>
+      </div>
+    `);
+  });
 });

packages/react-router/lib/hooks.tsx

@@ -8,9 +8,9 @@ import type {
   PathPattern,
   Router as RemixRouter,
   To,
-  Action as NavigationType,
 } from "@remix-run/router";
 import {
+  Action as NavigationType,
   invariant,
   isRouteErrorResponse,
   joinPaths,
@@ -425,7 +425,7 @@ export function useRoutes(
     );
   }
 
-  return _renderMatches(
+  let renderedMatches = _renderMatches(
     matches &&
       matches.map((match) =>
         Object.assign({}, match, {
@@ -440,6 +440,31 @@ export function useRoutes(
     parentMatches,
     dataRouterStateContext || undefined
   );
+
+  // When a user passes in a `locationArg`, the associated routes need to
+  // be wrapped in a new `LocationContext.Provider` in order for `useLocation`
+  // to use the scoped location instead of the global location.
+  if (locationArg) {
+    return (
+      <LocationContext.Provider
+        value={{
+          location: {
+            pathname: "/",
+            search: "",
+            hash: "",
+            state: null,
+            key: "default",
+            ...location,
+          },
+          navigationType: NavigationType.Pop,
+        }}
+      >
+        {renderedMatches}
+      </LocationContext.Provider>
+    );
+  }
+
+  return renderedMatches;
 }
 
 function DefaultErrorElement() {