Merge branch 'MDL-76649_400' of https://github.com/timhunt/moodle int…

…o MOODLE_400_STABLE

lib/moodlelib.php

@@ -9280,6 +9280,25 @@ function mtrace($string, $eol="\n", $sleep=0) {
     }
 }
 
+/**
+ * Helper to {@see mtrace()} an exception or throwable, including all relevant information.
+ *
+ * @param Throwable $e the error to ouptput.
+ */
+function mtrace_exception(Throwable $e): void {
+    $info = get_exception_info($e);
+
+    $message = $info->message;
+    if ($info->debuginfo) {
+        $message .= "\n\n" . $info->debuginfo;
+    }
+    if ($info->backtrace) {
+        $message .= "\n\n" . format_backtrace($info->backtrace, true);
+    }
+
+    mtrace($message);
+}
+
 /**
  * Replace 1 or more slashes or backslashes to 1 slash
  *

lib/setuplib.php

@@ -499,11 +499,12 @@ function print_error($errorcode, $module = 'error', $link = '', $a = null, $debu
 
 /**
  * Returns detailed information about specified exception.
- * @param exception $ex
- * @return object
+ *
+ * @param Throwable $ex any sort of exception or throwable.
+ * @return stdClass standardised info to display. Fields are clear if you look at the end of this function.
  */
-function get_exception_info($ex) {
-    global $CFG, $DB, $SESSION;
+function get_exception_info($ex): stdClass {
+    global $CFG;
 
     if ($ex instanceof moodle_exception) {
         $errorcode = $ex->errorcode;

lib/upgrade.txt

@@ -1,7 +1,12 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
+=== 4.0.6 ===
+
+* There is a new helper function mtrace_exception to help with reporting exceptions you have caught in scheduled tasks.
+
 === 4.0.5 ===
+
 * For plugins that override secondary navigation, the namespace for the custom secondary navigation class has
   changed. It was (for example) mod_mymodule\local\views\secondary but is now
   mod_mymodule\navigation\views\secondary. The old location will continue to work, but will be deprecated in 4.1.

mod/quiz/report/statistics/classes/task/recalculate.php

@@ -36,21 +36,33 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class recalculate extends \core\task\scheduled_task {
+    /** @var int the maximum length of time one instance of this task will run. */
+    const TIME_LIMIT = 3600;
 
-    public function get_name() {
+    public function get_name(): string {
         return get_string('recalculatetask', 'quiz_statistics');
     }
 
-    public function execute() {
+    public function execute(): void {
         global $DB;
+        $stoptime = time() + self::TIME_LIMIT;
+        $dateformat = get_string('strftimedatetimeshortaccurate', 'core_langconfig');
+
         // TODO: MDL-75197, add quizid in quiz_statistics so that it is simpler to find quizzes for stats calculation.
         // Only calculate stats for quizzes which have recently finished attempt.
         $sql = "
-            SELECT qa.quiz, MAX(qa.timefinish) as timefinish
+            SELECT q.id AS quizid,
+                   q.name AS quizname,
+                   c.id AS courseid,
+                   c.shortname AS courseshortname,
+                   MAX(qa.timefinish) AS mostrecentattempttime,
+                   COUNT(1) AS numberofattempts
               FROM {quiz_attempts} qa
+              JOIN {quiz} q ON q.id = qa.quiz
+              JOIN {course} c ON c.id = q.course
              WHERE qa.preview = 0
                AND qa.state = :quizstatefinished
-          GROUP BY qa.quiz
+          GROUP BY q.id, q.name, c.id, c.shortname
         ";
 
         $params = [
@@ -59,30 +71,50 @@ public function execute() {
 
         $latestattempts = $DB->get_records_sql($sql, $params);
 
+        $anyexception = null;
         foreach ($latestattempts as $attempt) {
-            $quizobj = quiz::create($attempt->quiz);
+            if (time() >= $stoptime) {
+                mtrace("This task has been running for more than " .
+                        format_time(self::TIME_LIMIT) . " so stopping this execution.");
+                break;
+            }
+
+            mtrace("  Examining quiz '$attempt->quizname' ($attempt->quizid) in course " .
+                    "$attempt->courseshortname ($attempt->courseid) with most recent attempt at " .
+                    userdate($attempt->mostrecentattempttime, $dateformat) . ".");
+            $quizobj = quiz::create($attempt->quizid);
             $quiz = $quizobj->get_quiz();
             // Hash code for question stats option in question bank.
             $qubaids = quiz_statistics_qubaids_condition($quiz->id, new \core\dml\sql_join(), $quiz->grademethod);
 
             // Check if there is any existing question stats, and it has been calculated after latest quiz attempt.
-            $records = $DB->get_records_select(
-                'quiz_statistics',
-                'hashcode = :hashcode AND timemodified > :timefinish',
-                [
-                    'hashcode' => $qubaids->get_hash_code(),
-                    'timefinish' => $attempt->timefinish
-                ]
-            );
-
-            if (empty($records)) {
+            $lateststatstime = $DB->get_field('quiz_statistics', 'COALESCE(MAX(timemodified), 0)',
+                    ['hashcode' => $qubaids->get_hash_code()]);
+
+            if ($lateststatstime >= $attempt->mostrecentattempttime) {
+                mtrace("    Statistics already calculated at " . userdate($lateststatstime, $dateformat) .
+                        " so nothing to do for this quiz.");
+                continue;
+            }
+
+            mtrace("    Calculating statistics for $attempt->numberofattempts attempts, starting at " .
+                    userdate(time(), $dateformat) . " ...");
+            try {
                 $report = new quiz_statistics_report();
-                // Clear old cache.
                 $report->clear_cached_data($qubaids);
-                // Calculate new stats.
                 $report->calculate_questions_stats_for_question_bank($quiz->id);
+                mtrace("    Calculations completed at " . userdate(time(), $dateformat) . ".");
+
+            } catch (\Throwable $e) {
+                // We don't want an exception from one quiz to stop processing of other quizzes.
+                mtrace_exception($e);
+                $anyexception = $e;
             }
         }
-        return true;
+
+        if ($anyexception) {
+            // If there was any error, ensure the task fails.
+            throw $anyexception;
+        }
     }
 }