From ef9ca1069921604be53a3f2561bed1f43eb64f54 Mon Sep 17 00:00:00 2001
From: Ankit Agarwal <ankit@moodle.com>
Date: Thu, 12 Sep 2013 10:08:48 +0800
Subject: [PATCH] MDL-21415 reports: We should fetch active group from session
 not page params

Also donot allow active group to be set to something that user doesn't have access to
---
 lib/grouplib.php               | 19 +++++++++++++++----
 lib/tests/grouplib_test.php    |  8 ++++++--
 report/participation/index.php |  4 ++++
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/grouplib.php b/lib/grouplib.php
index b30dae5fab6..826d0c481db 100644
--- a/lib/grouplib.php
+++ b/lib/grouplib.php
@@ -581,13 +581,24 @@ function groups_allgroups_course_menu($course, $urlroot, $update = false, $activ
         $allowedgroups = groups_get_all_groups($course->id, $USER->id, $course->defaultgroupingid);
     }
 
-    if ($update) {
-        $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid] = $activegroup;
-    }
-
     foreach ($allowedgroups as $group) {
         $groupsmenu[$group->id] = format_string($group->name);
     }
+
+    if ($update) {
+        // Init activegroup array if necessary.
+        if (!isset($SESSION->activegroup)) {
+            $SESSION->activegroup = array();
+        }
+        if (!isset($SESSION->activegroup[$course->id])) {
+            $SESSION->activegroup[$course->id] = array(SEPARATEGROUPS => array(), VISIBLEGROUPS => array(), 'aag' => array());
+        }
+        if (empty($groupsmenu[$activegroup])) {
+            $activegroup = key($groupsmenu); // Force set to one of accessible groups.
+        }
+        $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid] = $activegroup;
+    }
+
     $grouplabel = get_string('groups');
     if (count($groupsmenu) == 0) {
         return '';
diff --git a/lib/tests/grouplib_test.php b/lib/tests/grouplib_test.php
index f88c153bc1a..ada661631d2 100644
--- a/lib/tests/grouplib_test.php
+++ b/lib/tests/grouplib_test.php
@@ -713,10 +713,14 @@ class core_grouplib_testcase extends advanced_testcase {
         $this->assertContains(format_string($group2->name), $html);
 
         // Let us test activegroup changes now.
+        $this->setUser($user);
         $SESSION->activegroup[$course->id][VISIBLEGROUPS][$course->defaultgroupingid] = 5;
         groups_allgroups_course_menu($course, 'someurl.php', false); // Do not update session.
         $this->assertSame(5, $SESSION->activegroup[$course->id][VISIBLEGROUPS][$course->defaultgroupingid]);
-        groups_allgroups_course_menu($course, 'someurl.php', true, 2); // Update session.
-        $this->assertSame(2, $SESSION->activegroup[$course->id][VISIBLEGROUPS][$course->defaultgroupingid]);
+        groups_allgroups_course_menu($course, 'someurl.php', true, $group1->id); // Update session.
+        $this->assertSame($group1->id, $SESSION->activegroup[$course->id][VISIBLEGROUPS][$course->defaultgroupingid]);
+        // Try to update session with an invalid groupid. It should not accept the invalid id.
+        groups_allgroups_course_menu($course, 'someurl.php', true, 256);
+        $this->assertEquals($group1->id, $SESSION->activegroup[$course->id][VISIBLEGROUPS][$course->defaultgroupingid]);
     }
 }
diff --git a/report/participation/index.php b/report/participation/index.php
index 6b6a7ab361a..f64c1d3d44e 100644
--- a/report/participation/index.php
+++ b/report/participation/index.php
@@ -176,6 +176,10 @@ if (empty($select)) {
     echo $select;
 }
 
+// Fetch current active group.
+$groupmode = groups_get_course_groupmode($course);
+$currentgroup = $SESSION->activegroup[$course->id][$groupmode][$course->defaultgroupingid];
+
 if (!empty($instanceid) && !empty($roleid)) {
     // from here assume we have at least the module we're using.
     $cm = $modinfo->cms[$instanceid];