From fdd88910912c3fff0c78db3398ae6e6838f4f210 Mon Sep 17 00:00:00 2001
From: Andrew Nicols <andrew@nicols.co.uk>
Date: Thu, 27 Feb 2025 20:14:07 +0800
Subject: [PATCH] MDL-84543 core: Basepath guess should work on root domains

---
 lib/classes/router.php    |  2 +-
 lib/tests/router_test.php | 19 ++++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/lib/classes/router.php b/lib/classes/router.php
index c654042f22e..f74ffa86834 100644
--- a/lib/classes/router.php
+++ b/lib/classes/router.php
@@ -91,7 +91,7 @@ class router {
 
         // Moodle is not guaranteed to exist at the domain root.
         // Strip out the current script.
-        $scriptroot = parse_url($CFG->wwwroot, PHP_URL_PATH);
+        $scriptroot = parse_url($CFG->wwwroot, PHP_URL_PATH) ?? '';
         $scriptfile = str_replace(
             realpath($CFG->dirroot),
             '',
diff --git a/lib/tests/router_test.php b/lib/tests/router_test.php
index c8ccb54c7b4..980f0e4fc51 100644
--- a/lib/tests/router_test.php
+++ b/lib/tests/router_test.php
@@ -88,13 +88,26 @@ final class router_test extends route_testcase {
         $this->assertEquals('/example', $router->basepath);
     }
 
-    public function test_basepath_guessed(): void {
+    /**
+     * @dataProvider basepath_provider
+     */
+    public function test_basepath(
+        string $wwwroot,
+        string $expected,
+    ): void {
         global $CFG;
 
-        $wwwroot = new \moodle_url($CFG->wwwroot);
+        $this->resetAfterTest();
+        $CFG->wwwroot = $wwwroot;
+
         $router = di::get(router::class);
 
-        $this->assertEquals($wwwroot->get_path(), $router->basepath);
+        $this->assertEquals($expected, $router->basepath);
+    }
+
+    public static function basepath_provider(): \Iterator {
+        yield 'Domain' => ['http://example.com', ''];
+        yield 'Subdirectory' => ['http://example.com/moodle', '/moodle'];
     }
 
     public function test_basepath_guessed_rphp(): void {