From 38ff4d528ee6d93c31e42476b252272db7b1af04 Mon Sep 17 00:00:00 2001
From: Jake Dallimore <jake@moodle.com>
Date: Fri, 20 Aug 2021 15:47:31 +0800
Subject: [PATCH] MDL-69504 mod_lti: check role switches when setting lti roles
 on launch

is_siteadmin isn't aware of role switches, so make sure we're not in a
switched role before calling that method.
---
 mod/lti/locallib.php            |  2 +-
 mod/lti/tests/locallib_test.php | 95 +++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+), 1 deletion(-)

diff --git a/mod/lti/locallib.php b/mod/lti/locallib.php
index ae27f4a2528..b14a4cdddb7 100644
--- a/mod/lti/locallib.php
+++ b/mod/lti/locallib.php
@@ -2165,7 +2165,7 @@ function lti_get_ims_role($user, $cmid, $courseid, $islti2) {
         }
     }
 
-    if (is_siteadmin($user) || has_capability('mod/lti:admin', $context)) {
+    if (!is_role_switched($courseid) && (is_siteadmin($user)) || has_capability('mod/lti:admin', $context)) {
         // Make sure admins do not have the Learner role, then set admin role.
         $roles = array_diff($roles, array('Learner'));
         if (!$islti2) {
diff --git a/mod/lti/tests/locallib_test.php b/mod/lti/tests/locallib_test.php
index 51b7362edb8..79ff5208ceb 100644
--- a/mod/lti/tests/locallib_test.php
+++ b/mod/lti/tests/locallib_test.php
@@ -1740,6 +1740,101 @@ MwIDAQAB
         $this->assertEquals(get_course_history($course), [38903]);
     }
 
+    /**
+     * Test the lti_get_ims_role helper function.
+     *
+     * @dataProvider lti_get_ims_role_provider
+     * @param bool $islti2 whether the method is called with LTI 2.0 role names or not.
+     * @param string $rolename the name of the role (student, teacher, admin)
+     * @param null|string $switchedto the role to switch to, or false if not using the 'switch to' functionality.
+     * @param string $expected the expected role name.
+     */
+    public function test_lti_get_ims_role(bool $islti2, string $rolename, ?string $switchedto, string $expected) {
+        global $DB;
+        $this->resetAfterTest();
+
+        $course = $this->getDataGenerator()->create_course();
+        $user = $rolename == 'admin' ? get_admin() : $this->getDataGenerator()->create_and_enrol($course, $rolename);
+
+        if ($switchedto) {
+            $this->setUser($user);
+            $role = $DB->get_record('role', array('shortname' => $switchedto));
+            role_switch($role->id, context_course::instance($course->id));
+        }
+
+        $this->assertEquals($expected, lti_get_ims_role($user, 0, $course->id, $islti2));
+    }
+
+    /**
+     * Data provider for testing lti_get_ims_role.
+     *
+     * @return array[] the test case data.
+     */
+    public function lti_get_ims_role_provider() {
+        return [
+            'Student, LTI 1.1, no role switch' => [
+                'islti2' => false,
+                'rolename' => 'student',
+                'switchedto' => null,
+                'expected' => 'Learner'
+            ],
+            'Student, LTI 2.0, no role switch' => [
+                'islti2' => true,
+                'rolename' => 'student',
+                'switchedto' => null,
+                'expected' => 'Learner'
+            ],
+            'Teacher, LTI 1.1, no role switch' => [
+                'islti2' => false,
+                'rolename' => 'editingteacher',
+                'switchedto' => null,
+                'expected' => 'Instructor'
+            ],
+            'Teacher, LTI 2.0, no role switch' => [
+                'islti2' => true,
+                'rolename' => 'editingteacher',
+                'switchedto' => null,
+                'expected' => 'Instructor'
+            ],
+            'Admin, LTI 1.1, no role switch' => [
+                'islti2' => false,
+                'rolename' => 'admin',
+                'switchedto' => null,
+                'expected' => 'Instructor,urn:lti:sysrole:ims/lis/Administrator,urn:lti:instrole:ims/lis/Administrator'
+            ],
+            'Admin, LTI 2.0, no role switch' => [
+                'islti2' => true,
+                'rolename' => 'admin',
+                'switchedto' => null,
+                'expected' => 'Instructor,http://purl.imsglobal.org/vocab/lis/v2/person#Administrator'
+            ],
+            'Admin, LTI 1.1, role switch student' => [
+                'islti2' => false,
+                'rolename' => 'admin',
+                'switchedto' => 'student',
+                'expected' => 'Learner'
+            ],
+            'Admin, LTI 2.0, role switch student' => [
+                'islti2' => true,
+                'rolename' => 'admin',
+                'switchedto' => 'student',
+                'expected' => 'Learner'
+            ],
+            'Admin, LTI 1.1, role switch teacher' => [
+                'islti2' => false,
+                'rolename' => 'admin',
+                'switchedto' => 'editingteacher',
+                'expected' => 'Instructor'
+            ],
+            'Admin, LTI 2.0, role switch teacher' => [
+                'islti2' => true,
+                'rolename' => 'admin',
+                'switchedto' => 'editingteacher',
+                'expected' => 'Instructor'
+            ],
+        ];
+    }
+
     /**
      * Create an LTI Tool.
      *