MDL-37206 preload course format renderer in course/view.php

Also fixed bug with hardcoded default 'weeks' format

course/view.php

@@ -117,15 +117,25 @@
     }
     add_to_log($course->id, 'course', $loglabel, "view.php?". $logparam, $infoid);
 
-    $course->format = clean_param($course->format, PARAM_ALPHA);
-    if (!file_exists($CFG->dirroot.'/course/format/'.$course->format.'/format.php')) {
-        $course->format = 'weeks';  // Default format is weeks
-    }
+    // Fix course format if it is no longer installed
+    $course->format = course_get_format($course)->get_format();
 
     $PAGE->set_pagelayout('course');
     $PAGE->set_pagetype('course-view-' . $course->format);
     $PAGE->set_other_editing_capability('moodle/course:manageactivities');
 
+    // Preload course format renderer before output starts.
+    // This is a little hacky but necessary since
+    // format.php is not included until after output starts
+    if (file_exists($CFG->dirroot.'/course/format/'.$course->format.'/renderer.php')) {
+        require_once($CFG->dirroot.'/course/format/'.$course->format.'/renderer.php');
+        if (class_exists('format_'.$course->format.'_renderer')) {
+            // call get_renderer only if renderer is defined in format plugin
+            // otherwise an exception would be thrown
+            $PAGE->get_renderer('format_'. $course->format);
+        }
+    }
+
     if ($reset_user_allowed_editing) {
         // ugly hack
         unset($PAGE->_user_allowed_editing);