diff --git a/mod/workshop/allocation.php b/mod/workshop/allocation.php
index 049948c10ea..b1954a56d9f 100644
--- a/mod/workshop/allocation.php
+++ b/mod/workshop/allocation.php
@@ -38,7 +38,7 @@ $PAGE->set_url('mod/workshop/allocation.php', array('cmid' => $cmid, 'method' =>
 $cm         = get_coursemodule_from_id('workshop', $cmid, 0, false, MUST_EXIST);
 $course     = $DB->get_record('course', array('id' => $cm->course), '*', MUST_EXIST);
 $workshop   = $DB->get_record('workshop', array('id' => $cm->instance), '*', MUST_EXIST);
-$workshop   = new workshop_api($workshop, $cm);
+$workshop   = new workshop_api($workshop, $cm, $course);
 
 require_login($course, false, $cm);
 $context = $PAGE->context;
diff --git a/mod/workshop/allocation/random/allocator.php b/mod/workshop/allocation/random/allocator.php
index 1d9209b457e..fb0fcfbc25a 100644
--- a/mod/workshop/allocation/random/allocator.php
+++ b/mod/workshop/allocation/random/allocator.php
@@ -333,6 +333,10 @@ class workshop_random_allocator implements workshop_allocator {
      * @return array                 array of (reviewerid => authorid) pairs
      */
     protected function random_allocation($authors, $reviewers, $assessments, $numofreviews, $numper, &$o) {
+        if (empty($authors) || empty($reviewers)) {
+            // nothing to be done
+            return array();
+        }
         if (WORKSHOP_USERTYPE_AUTHOR == $numper) {
             // circles are authors, squares are reviewers
             $o[] = 'info::Trying to allocate ' . $numofreviews . ' review(s) per author'; // todo translate
@@ -368,7 +372,7 @@ class workshop_random_allocator implements workshop_allocator {
         unset($squaregroupsworkload[0]);    // [0] is not real group, it contains all users
         $o[] = 'debug::square workload = ' . json_encode($squareworkload);
         $o[] = 'debug::square group workload = ' . json_encode($squaregroupsworkload);
-        $gmode = groups_get_activity_groupmode($this->workshop->cm);
+        $gmode = groups_get_activity_groupmode($this->workshop->cm, $this->workshop->courserecord);
         if (SEPARATEGROUPS == $gmode) {
             // shuffle all groups but [0] which means "all users"
             $circlegroups = array_keys(array_diff_key($allcircles, array(0 => null)));
diff --git a/mod/workshop/allocation/random/settings_form.php b/mod/workshop/allocation/random/settings_form.php
index 2e7930f58df..7299343f888 100644
--- a/mod/workshop/allocation/random/settings_form.php
+++ b/mod/workshop/allocation/random/settings_form.php
@@ -46,7 +46,8 @@ class workshop_random_allocator_form extends moodleform {
 
         $mform->addElement('header', 'settings', get_string('allocationsettings', 'workshop'));
 
-        switch ($workshop->cm->groupmode) {
+        $gmode = groups_get_activity_groupmode($workshop->cm, $workshop->courserecord);
+        switch ($gmode) {
         case NOGROUPS:
             $grouplabel = get_string('groupsnone', 'group');
             break;
diff --git a/mod/workshop/allocation/random/simpletest/testallocator.php b/mod/workshop/allocation/random/simpletest/testallocator.php
index 63e6a48e19f..c08f7b1f0b0 100644
--- a/mod/workshop/allocation/random/simpletest/testallocator.php
+++ b/mod/workshop/allocation/random/simpletest/testallocator.php
@@ -67,7 +67,7 @@ class workshop_allocation_random_test extends UnitTestCase {
     protected $allocator;
 
     public function setUp() {
-        $this->workshop     = new workshop((object)array('id' => 42), new stdClass());
+        $this->workshop     = new workshop((object)array('id' => 42), new stdClass(), new stdClass());
         $this->allocator    = new testable_workshop_random_allocator($this->workshop);
     }
 
diff --git a/mod/workshop/assessment.php b/mod/workshop/assessment.php
index 7968eec80f0..639fc8f2174 100644
--- a/mod/workshop/assessment.php
+++ b/mod/workshop/assessment.php
@@ -64,7 +64,7 @@ if ($preview = optional_param('preview', 0, PARAM_INT)) {
 
 require_login($course, false, $cm);
 
-$workshop = new workshop_api($workshop, $cm);
+$workshop = new workshop_api($workshop, $cm, $course);
 
 $context = $PAGE->context;
 
diff --git a/mod/workshop/editform.php b/mod/workshop/editform.php
index eabdbe9ade4..976b074c4db 100644
--- a/mod/workshop/editform.php
+++ b/mod/workshop/editform.php
@@ -48,7 +48,7 @@ if (!$workshop = $DB->get_record('workshop', array('id' => $cm->instance))) {
     print_error('err_invalidworkshopid', 'workshop');
 }
 
-$workshop = new workshop_api($workshop, $cm)l
+$workshop = new workshop_api($workshop, $cm, $course);
 
 // where should the user be sent after closing the editing form
 $returnurl  = "{$CFG->wwwroot}/mod/workshop/view.php?id={$cm->id}";
diff --git a/mod/workshop/lib.php b/mod/workshop/lib.php
index 3b719c258b2..9c8d0ebd0b3 100644
--- a/mod/workshop/lib.php
+++ b/mod/workshop/lib.php
@@ -50,25 +50,30 @@ define('WORKSHOP_COMPARISON_VERYHIGH',  4);     /* f = 5.00 */
 /**
  * The base class of workshop instances
  *
+ * It defines methods that are part of any activity module API and may be called by Moodle core.
  * The class just wraps the database record from the {workshop} table and adds some
  * methods that implement the compulsory activity module API.
- * For full-featured class see {@link workshop_api}.
+ * For full-featured workshop class see {@link workshop_api}.
  */
 class workshop {
 
-    /** course module record */
+    /** @var object course module record */
     public $cm;
 
+    /** @var object course record */
+    public $courserecord;
+
     /**
-     * Defines methods that are part of any activity module API and may be called by Moodle core
      *
      * Initializes the object using the data from DB. Makes deep copy of all $dbrecord properties.
+     * Please do not confuse $this->course (integer property from the database record) and
+     * $this->courserecord (object containing the whole course record).
      *
-     * @param object $instance  The instance data row from {workshop} table
-     * @param object $cm        Course module record
+     * @param object $instance     The instance data row from {workshop} table
+     * @param object $cm           Course module record
+     * @param object $courserecord Course record
      */
-    public function __construct(stdClass $instance, stdClass $cm) {
-
+    public function __construct(stdClass $instance, stdClass $cm, stdClass $courserecord) {
         foreach ($instance as $key => $val) {
             if (is_object($val) || (is_array($val))) {
                 // this should not happen if the $dbrecord is really just the record returned by $DB
@@ -78,6 +83,7 @@ class workshop {
             }
         }
         $this->cm = $cm;
+        $this->courserecord = $courserecord;
     }
 
     /**
@@ -114,6 +120,8 @@ function workshop_add_instance($data) {
     return workshop::add_instance($data);
 }
 
+// TODO convert following functions into workshop methods
+
 /**
  * Given an object containing all the necessary data,
  * (defined by the form in mod_form.php) this function
diff --git a/mod/workshop/locallib.php b/mod/workshop/locallib.php
index bdc3b1e69e0..e4dbec8e504 100644
--- a/mod/workshop/locallib.php
+++ b/mod/workshop/locallib.php
@@ -49,13 +49,13 @@ class workshop_api extends workshop {
     /**
      * Initialize the object using the data from DB
      *
-     * @param object $instance  The instance data row from {workshop} table
-     * @param object $md        Course module record
-     */
-    public function __construct($instance, $cm) {
-
-        parent::__construct($instance, $cm);
+     * @param object $instance     The instance data row from {workshop} table
+     * @param object $cm           Course module record
+     * @param object $courserecord Course record
+    public function __construct($instance, $cm, $courserecord) {
+        parent::__construct($instance, $cm, $courserecord);
     }
+     */
 
     /**
      * Fetches all users with the capability mod/workshop:submit in the current context
@@ -103,6 +103,9 @@ class workshop_api extends workshop {
 
         $authors    = $this->get_peer_authors($musthavesubmission);
         $gauthors   = array();  // grouped authors to be returned
+        if (empty($authors)) {
+            return $gauthors;
+        }
         if ($this->cm->groupmembersonly) {
             // Available for group members only - the workshop is available only
             // to users assigned to groups within the selected grouping, or to
@@ -174,6 +177,9 @@ class workshop_api extends workshop {
 
         $reviewers  = $this->get_peer_reviewers($musthavesubmission);
         $greviewers = array();  // grouped reviewers to be returned
+        if (empty($reviewers)) {
+            return $greviewers;
+        }
         if ($this->cm->groupmembersonly) {
             // Available for group members only - the workshop is available only
             // to users assigned to groups within the selected grouping, or to
diff --git a/mod/workshop/view.php b/mod/workshop/view.php
index 027cdeaff26..be43882fa87 100644
--- a/mod/workshop/view.php
+++ b/mod/workshop/view.php
@@ -42,7 +42,7 @@ if ($id) {
     $cm         = get_coursemodule_from_instance('workshop', $workshop->id, $course->id, false, MUST_EXIST);
 }
 
-$workshop = new workshop_api($workshop, $cm);
+$workshop = new workshop_api($workshop, $cm, $course);
 require_login($course, true, $cm);
 $context = $PAGE->context;