Fixed a potential bug that would have hit if one quiz would have had …

…two random questions for the same category, one of which was set to recurse into subcategories and the other not.

At the same time this improves performance because no longer all the potential questions are loaded from the database but only their ids.

mod/quiz/questiontypes/random/questiontype.php

@@ -42,7 +42,7 @@ function create_session_and_responses(&$question, &$state, $cmoptions, $attempt)
             $cmoptions->questionsinuse = $attempt->layout;
         }
 
-        if (!isset($this->catrandoms[$question->category])) {
+        if (!isset($this->catrandoms[$question->category][$question->questiontext])) {
             // Need to fetch random questions from category $question->category"
             // (Note: $this refers to the questiontype, not the question.)
             global $CFG;
@@ -53,23 +53,22 @@ function create_session_and_responses(&$question, &$state, $cmoptions, $attempt)
             } else {
                 $categorylist = $question->category;
             }
-            $this->catrandoms[$question->category] = get_records_sql
-                    ("SELECT * FROM {$CFG->prefix}quiz_questions
+            $catrandoms = get_records_sql
+                    ("SELECT id,id FROM {$CFG->prefix}quiz_questions
                        WHERE category IN ($categorylist)
                          AND parent = '0'
                          AND id NOT IN ($cmoptions->questionsinuse)
                          AND qtype NOT IN ($excludedtypes)");
-            $this->catrandoms[$question->category] =
-                  draw_rand_array($this->catrandoms[$question->category],
-                            count($this->catrandoms[$question->category])); // from bug 1889
+            $this->catrandoms[$question->category][$question->questiontext] =
+                  draw_rand_array(catrandoms, count($catrandoms)); // from bug 1889
         }
 
         while ($wrappedquestion =
-                array_pop($this->catrandoms[$question->category])) {
+                array_pop($this->catrandoms[$question->category][$question->questiontext])) {
             if (!ereg("(^|,)$wrappedquestion->id(,|$)", $cmoptions->questionsinuse)) {
                 /// $randomquestion is not in use and will therefore be used
                 /// as the randomquestion here...
-
+                $wrappedquestion = get_record('quiz_questions', 'id', $wrappedquestion->id);
                 global $QUIZ_QTYPES;
                 $QUIZ_QTYPES[$wrappedquestion->qtype]
                  ->get_question_options($wrappedquestion);