MDL-80099 quiz: Replace quiz_structure_modified callback with hook

This adds a new structure_modified hook to mod_quiz, deprecating the
quiz_stucture_modified class callback used in
recompute_quiz_sumgrades(). The callback will be removed in Moodle 4.8.

The quiz_statsitics plugin which used this callback now defines a hook
callback instead.

mod/quiz/classes/grade_calculator.php

@@ -18,6 +18,7 @@ namespace mod_quiz;
 
 use coding_exception;
 use mod_quiz\event\quiz_grade_updated;
+use mod_quiz\hook\structure_modified;
 use question_engine_data_mapper;
 use stdClass;
 
@@ -92,10 +93,14 @@ class grade_calculator {
             self::update_quiz_maximum_grade(0);
         }
 
+        // This class callback is deprecated, and will be removed in Moodle 4.8 (MDL-80327).
+        // Use the structure_modified hook instead.
         $callbackclasses = \core_component::get_plugin_list_with_class('quiz', 'quiz_structure_modified');
         foreach ($callbackclasses as $callbackclass) {
-            component_class_callback($callbackclass, 'callback', [$quiz->id]);
+            component_class_callback($callbackclass, 'callback', [$quiz->id], null, true);
         }
+
+        \core\hook\manager::get_instance()->dispatch(new structure_modified($this->quizobj->get_structure()));
     }
 
     /**

mod/quiz/classes/hook/structure_modified.php

@@ -0,0 +1,51 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+namespace mod_quiz\hook;
+
+use core\attribute;
+use mod_quiz\structure;
+
+/**
+ * The quiz structure has been modified
+ *
+ * @package   mod_quiz
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+#[attribute\label('The quiz structure has been modified')]
+#[attribute\tags('quiz', 'structure')]
+#[attribute\hook\replaces_callbacks('quiz_structure_modified::callback')]
+class structure_modified {
+    /**
+     * Create a new hook with the modified structure.
+     *
+     * @param structure $structure The new structure.
+     */
+    public function __construct(
+        protected structure $structure
+    ) {
+    }
+
+    /**
+     * Returns the new structure of the quiz.
+     *
+     * @return structure The structure object.
+     */
+    public function get_structure(): structure {
+        return $this->structure;
+    }
+}

mod/quiz/report/statistics/classes/hook_callbacks.php

@@ -13,34 +13,31 @@
 //
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
-
 namespace quiz_statistics;
 
 use core\dml\sql_join;
+use mod_quiz\hook\structure_modified;
 
 /**
- * Clear the statistics cache when the quiz structure is modified.
+ * Hook callbacks
  *
  * @package   quiz_statistics
  * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
  * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class quiz_structure_modified {
+class hook_callbacks {
     /**
-     * Clear the statistics cache.
+     * Clear the statistics cache for the quiz where the structure was modified.
      *
-     * @param int $quizid The quiz to clear the cache for.
+     * @param structure_modified $hook The structure_modified hook containing the new structure.
      * @return void
      */
-    public static function callback(int $quizid): void {
-        global $DB, $CFG;
+    public static function quiz_structure_modified(structure_modified $hook) {
+        global $CFG;
         require_once($CFG->dirroot . '/mod/quiz/report/statistics/statisticslib.php');
         require_once($CFG->dirroot . '/mod/quiz/report/statistics/report.php');
-        $quiz = $DB->get_record('quiz', ['id' => $quizid]);
-        if (!$quiz) {
-            throw new \coding_exception('Could not find quiz with ID ' . $quizid . '.');
-        }
+        $quiz = $hook->get_structure()->get_quiz();
         $qubaids = quiz_statistics_qubaids_condition(
             $quiz->id,
             new sql_join(),

mod/quiz/report/statistics/db/hooks.php

@@ -0,0 +1,32 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+/**
+ * Hook callback definitions for quiz_statistics
+ *
+ * @package   quiz_statistics
+ * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
+ * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+defined('MOODLE_INTERNAL') || die();
+
+$callbacks = [
+    [
+        'hook' => mod_quiz\hook\structure_modified::class,
+        'callback' => quiz_statistics\hook_callbacks::class . '::quiz_structure_modified',
+        'priority' => 500,
+    ],
+];