MDL-11398 - Random questions sometimes ended up with names different …

…from the cateogry they were actually picking from. Also, the same random questoin could be used in more than one quiz, in which case editing that question would change two quizzes unexpectedly. The fix is:

* Don't let the user set the name for random questions.
* Instead force the name to be "Random (catname)" (localised) whever the question is created or saved.
* When a category is renamed, rename all the random questions in it.
* Remove the restriction that Jamie seems to have added in 1.9 that was preventing the category of random questions from being edited.

mod/quiz/edit.php

@@ -184,40 +184,31 @@ function module_specific_controls($totalnumber, $recurse, $category, $cmid){
         $catcontext = get_context_instance_by_id($category->contextid);
         require_capability('moodle/question:useall', $catcontext);
         $category->name = addslashes($category->name);
-        // find existing random questions in this category
-        $random = RANDOM;
-        if ($existingquestions = get_records_select('question', "qtype = '$random' AND category = '$category->id'")) {
-            // now remove the ones that are already used in this quiz
-            if ($questionids = explode(',', $quiz->questions)) {
-                foreach ($questionids as $questionid) {
-                    unset($existingquestions[$questionid]);
-                }
-            }
-            // now take as many of these as needed
-            $i = 0;
-            while (($existingquestion = array_pop($existingquestions)) and ($i < $randomcount)) {
-                if ($existingquestion->questiontext == $recurse) {
-                    // this question has the right recurse property, so use it
-                    quiz_add_quiz_question($existingquestion->id, $quiz);
-                    $i++;
-                }
+        // Find existing random questions in this category that are not used by any quiz.
+        if ($existingquestions = get_records_sql(
+                "SELECT * FROM " . $CFG->prefix . "question q
+                WHERE qtype = '" . RANDOM . "'
+                    AND category = $category->id
+                    AND " . sql_compare_text('questiontext') . " = '$recurse'
+                    AND NOT EXISTS (SELECT * FROM " . $CFG->prefix . "quiz_question_instances WHERE question = q.id)
+                ORDER BY id")) {
+            // Take as many of these as needed.
+            while (($existingquestion = array_shift($existingquestions)) and $randomcount > 0) {
+                quiz_add_quiz_question($existingquestion->id, $quiz);
+                $randomcount--;
             }
-            $randomcreate = $randomcount - $i; // the number of additional random questions needed.
-        } else {
-            $randomcreate = $randomcount;
         }
 
-        if ($randomcreate > 0) {
-
-            $form->name = get_string('random', 'quiz') .' ('. $category->name .')';
-            $form->category = "$category->id,$category->contextid";
+        // If more are needed, create them.
+        if ($randomcount > 0) {
             $form->questiontext = $recurse; // we use the questiontext field to store the info
                                             // on whether to include questions in subcategories
             $form->questiontextformat = 0;
             $form->image = '';
             $form->defaultgrade = 1;
             $form->hidden = 1;
-            for ($i=0; $i<$randomcreate; $i++) {
+            for ($i = 0; $i < $randomcount; $i++) {
+                $form->category = "$category->id,$category->contextid";
                 $form->stamp = make_unique_id_code();  // Set the unique code (not to be changed)
                 $question = new stdClass;
                 $question->qtype = RANDOM;

question/category_class.php

@@ -417,6 +417,14 @@ function update_category($updateid, $newparent, $newname, $newinfo) {
         $cat->info = $newinfo;
         //never move category where it is the default
         if (1 != count_records_sql("SELECT count(*) FROM {$CFG->prefix}question_categories c1, {$CFG->prefix}question_categories c2 WHERE c2.id = $updateid AND c1.contextid = c2.contextid")){
+            // If the question name has changed, rename any random questions in that category.
+            if ($oldcat->name != $cat->name) {
+                $randomqname = $QTYPES[RANDOM]->question_name($cat);
+                set_field('question', 'name', $randomqname, 'category', $cat->id, 'qtype', RANDOM);
+                // Ignore errors here. It is not a big deal if the questions are not renamed.
+            }
+
+            // Then update the category itself.
             if ($oldcat->contextid == $tocontextid){ // not moving contexts
                 $cat->parent = $parentid;
                 if (!update_record("question_categories", $cat)) {

question/type/questiontype.php

@@ -272,13 +272,10 @@ function save_question($question, $form, $course) {
         if (!empty($question->id)) { // Question already exists
             if (isset($form->categorymoveto)){
                 question_require_capability_on($question, 'move');
-                list($question->categorymoveto, $movetocontextid) = explode(',', $form->categorymoveto);
+                list($question->category, $movetocontextid) = explode(',', $form->categorymoveto);
                 //don't need to test add permission of category we are moving question to.
                 //Only categories that we have permission to add
                 //a question to will get through the form cleaning code for the select box.
-                if (isset($question->qtype) && $question->qtype != RANDOM){
-                    $question->category = $question->categorymoveto;
-                }
             }
             // keep existing unique stamp code
             $question->stamp = get_field('question', 'stamp', 'id', $question->id);

question/type/random/edit_random_form.php

@@ -34,11 +34,6 @@ function definition() {
         $mform->addElement('questioncategory', 'category', get_string('category', 'quiz'), 
                 array('contexts' => $this->contexts->having_cap('moodle/question:useall')));
 
-        $mform->addElement('text', 'name', get_string('questionname', 'quiz'),
-                array('size' => 50));
-        $mform->setType('name', PARAM_TEXT);
-        $mform->addRule('name', null, 'required', null, 'client');
-
         $mform->addElement('advcheckbox', 'questiontext', get_string("recurse", "quiz"), null, null, array(0, 1));
 
         // Standard fields at the end of the form.
@@ -77,13 +72,6 @@ function definition() {
         $mform->closeHeaderBefore('buttonar');
     }
 
-    function set_data($question) {
-        if (empty($question->name)) {
-            $question->name = get_string("random", "quiz");
-        }
-        parent::set_data($question);
-    }
-
     function qtype() {
         return 'random';
     }

question/type/random/questiontype.php

@@ -37,6 +37,32 @@ function get_question_options(&$question) {
         return true;
     }
 
+    /**
+     * Random questions always get a question name that is Random (cateogryname).
+     * This function is a centralised place to calculate that, given the category.
+     */
+    function question_name($category) {
+        return get_string('random', 'quiz') .' ('. $category->name .')';
+    }
+
+    function save_question($question, $form, $course) {
+        // If the category is changing, set things up as default_questiontype::save_question expects.
+        list($formcategory, $unused) = explode(',', $form->category);
+        if (isset($question->id) && $formcategory != $question->category) {
+            $form->categorymoveto = $form->category;
+        }
+        $form->name = '';
+        $question = parent::save_question($question, $form, $course);
+        if (!$category = get_record('question_categories', 'id', $question->category)) {
+            error('Could retrieve question category');
+        }
+        $question->name = $this->question_name($category);
+        if (!set_field('question', 'name', $question->name, 'id', $question->id)) {
+            error('Could not update random question name');
+        }
+        return $question;
+    }
+
     function save_question_options($question) {
         // No options, but we set the parent field to the question's own id.
         // Setting the parent field has the effect of hiding this question in