diff --git a/core/includes/path.inc b/core/includes/path.inc
index 630b34c..2c0568c 100644
--- a/core/includes/path.inc
+++ b/core/includes/path.inc
@@ -13,12 +13,11 @@
  * Initialize the $_GET['q'] variable to the proper normal path.
  */
 function drupal_path_initialize() {
-  if (!empty($_GET['q'])) {
-    $_GET['q'] = drupal_get_normal_path($_GET['q']);
-  }
-  else {
-    $_GET['q'] = drupal_get_normal_path(variable_get('site_frontpage', 'node'));
+  // Ensure $_GET['q'] is set before calling drupal_normal_path().
+  if (empty($_GET['q'])) {
+    $_GET['q'] = variable_get('site_frontpage', 'node');
   }
+  $_GET['q'] = drupal_get_normal_path($_GET['q']);
 }
 
 /**
diff --git a/core/modules/simpletest/tests/path.test b/core/modules/simpletest/tests/path.test
index 82598b5..9406a65 100644
--- a/core/modules/simpletest/tests/path.test
+++ b/core/modules/simpletest/tests/path.test
@@ -201,6 +201,14 @@ class UrlAlterFunctionalTest extends DrupalWebTestCase {
   }
 
   /**
+   * Tests that $_GET['q'] is initialized when the request path is empty.
+   */
+  function testGetQInitialized() {
+    $this->drupalGet('');
+    $this->assertText("\$_GET['q'] is non-empty with an empty request path.", "\$_GET['q'] is initialized with an empty request path.");
+  }
+
+  /**
    * Assert that an outbound path is altered to an expected value.
    *
    * @param $original
diff --git a/core/modules/simpletest/tests/url_alter_test.module b/core/modules/simpletest/tests/url_alter_test.module
index e229ab9..9287ff5 100644
--- a/core/modules/simpletest/tests/url_alter_test.module
+++ b/core/modules/simpletest/tests/url_alter_test.module
@@ -30,6 +30,10 @@ function url_alter_test_foo() {
  * Implements hook_url_inbound_alter().
  */
 function url_alter_test_url_inbound_alter(&$path, $original_path, $path_language) {
+  if (!request_path() && !empty($_GET['q'])) {
+    drupal_set_message("\$_GET['q'] is non-empty with an empty request path.");
+  }
+
   // Rewrite user/username to user/uid.
   if (preg_match('!^user/([^/]+)(/.*)?!', $path, $matches)) {
     if ($account = user_load_by_name($matches[1])) {