From 7dba450fd44c5f1fc6f1dc7d689c14e70c973707 Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Wed, 23 Nov 2016 22:57:36 +0800
Subject: [PATCH] MDL-57001 user_menu: Hide switch roles students

Check that there are switchable roles before showing the link in the user menu.
---
 user/lib.php | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/user/lib.php b/user/lib.php
index 283e1dc60aa55..cb0183dc3af15 100644
--- a/user/lib.php
+++ b/user/lib.php
@@ -929,18 +929,21 @@ function user_get_user_navigation_info($user, $page, $options = array()) {
 
         }
     } else {
-        // Build role-return link instead of logout link.
-        $switchrole = new stdClass();
-        $switchrole->itemtype = 'link';
-        $switchrole->url = new moodle_url('/course/switchrole.php', array(
-            'id' => $course->id,
-            'switchrole' => -1,
-            'returnurl' => $page->url->out_as_local_url(false)
-        ));
-        $switchrole->pix = "i/switchrole";
-        $switchrole->title = get_string('switchroleto');
-        $switchrole->titleidentifier = 'switchroleto,moodle';
-        $returnobject->navitems[] = $switchrole;
+        // Build switch role link.
+        $roles = get_switchable_roles($context);
+        if (is_array($roles) && (count($roles) > 0)) {
+            $switchrole = new stdClass();
+            $switchrole->itemtype = 'link';
+            $switchrole->url = new moodle_url('/course/switchrole.php', array(
+                'id' => $course->id,
+                'switchrole' => -1,
+                'returnurl' => $page->url->out_as_local_url(false)
+            ));
+            $switchrole->pix = "i/switchrole";
+            $switchrole->title = get_string('switchroleto');
+            $switchrole->titleidentifier = 'switchroleto,moodle';
+            $returnobject->navitems[] = $switchrole;
+        }
     }
 
     return $returnobject;