From 90ce66a9cee02c8271328ed35c0817bf03332c7c Mon Sep 17 00:00:00 2001
From: Paul Holden <paulh@moodle.com>
Date: Tue, 30 Jul 2019 07:55:50 +0100
Subject: [PATCH] MDL-66178 user: filter course participants for users with no
 roles.

---
 user/lib.php                                 | 12 +++++++++---
 user/renderer.php                            |  2 +-
 user/tests/behat/filter_participants.feature | 17 +++++++++++++++++
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/user/lib.php b/user/lib.php
index 477e614f59e..d38ad9bc0df 100644
--- a/user/lib.php
+++ b/user/lib.php
@@ -1293,7 +1293,7 @@ function user_get_tagged_users($tag, $exclusivemode = false, $fromctx = 0, $ctx
  * @param int $courseid The course id
  * @param int $groupid The groupid, 0 means all groups and USERSWITHOUTGROUP no group
  * @param int $accesssince The time since last access, 0 means any time
- * @param int $roleid The role id, 0 means all roles
+ * @param int $roleid The role id, 0 means all roles and -1 no roles
  * @param int $enrolid The enrolment id, 0 means all enrolment methods will be returned.
  * @param int $statusid The user enrolment status, -1 means all enrolments regardless of the status will be returned, if allowed.
  * @param string|array $search The search that was performed, empty means perform no search
@@ -1367,8 +1367,14 @@ function user_get_participants_sql($courseid, $groupid = 0, $accesssince = 0, $r
         list($relatedctxsql, $relatedctxparams) = $DB->get_in_or_equal($context->get_parent_context_ids(true),
             SQL_PARAMS_NAMED, 'relatedctx');
 
-        $wheres[] = "u.id IN (SELECT userid FROM {role_assignments} WHERE roleid = :roleid AND contextid $relatedctxsql)";
-        $params = array_merge($params, array('roleid' => $roleid), $relatedctxparams);
+        // Get users without any role.
+        if ($roleid == -1) {
+            $wheres[] = "u.id NOT IN (SELECT userid FROM {role_assignments} WHERE contextid $relatedctxsql)";
+            $params = array_merge($params, $relatedctxparams);
+        } else {
+            $wheres[] = "u.id IN (SELECT userid FROM {role_assignments} WHERE roleid = :roleid AND contextid $relatedctxsql)";
+            $params = array_merge($params, array('roleid' => $roleid), $relatedctxparams);
+        }
     }
 
     if (!empty($search)) {
diff --git a/user/renderer.php b/user/renderer.php
index 1e8461f695d..a1f22c1aa37 100644
--- a/user/renderer.php
+++ b/user/renderer.php
@@ -135,7 +135,7 @@ class core_user_renderer extends plugin_renderer_base {
         }
 
         $criteria = get_string('role');
-        $roleoptions = [];
+        $roleoptions = $this->format_filter_option(USER_FILTER_ROLE, $criteria, -1, get_string('noroles', 'role'));
         foreach ($roles as $id => $role) {
             $roleoptions += $this->format_filter_option(USER_FILTER_ROLE, $criteria, $id, $role);
         }
diff --git a/user/tests/behat/filter_participants.feature b/user/tests/behat/filter_participants.feature
index f0097f25a6c..13d815c8207 100644
--- a/user/tests/behat/filter_participants.feature
+++ b/user/tests/behat/filter_participants.feature
@@ -98,6 +98,23 @@ Feature: Course participants can be filtered
       | Group: Group A                  | Student 1 | Student 2 |           | Student 3    | XX-IGNORE-XX |
       | Group: Group B                  | Student 2 |           |           | Student 1    | Student 3    |
 
+  @javascript
+  Scenario: Filter users who have no role in a course
+    Given I log in as "teacher1"
+    And I am on "Course 1" course homepage
+    And I navigate to course participants
+    And I click on "Student 1's role assignments" "link"
+    And I click on ".form-autocomplete-selection [aria-selected=true]" "css_element"
+    And I press key "27" in the field "Student 1's role assignments"
+    And I click on "Save changes" "link"
+    When I open the autocomplete suggestions list
+    And I click on "Role: No roles" item in the autocomplete list
+    Then I should see "Student 1" in the "participants" "table"
+    And I should not see "Student 2" in the "participants" "table"
+    And I should not see "Student 3" in the "participants" "table"
+    And I should not see "Student 4" in the "participants" "table"
+    And I should not see "Teacher 1" in the "participants" "table"
+
   @javascript
   Scenario: Multiple filters applied
     Given I log in as "teacher1"
-- 
2.43.0