MDL-78902 quiz restore: fix restore of 3.x backups with random questions

... where the random questions come from the quiz module context.

Co-authored-by: Tim Hunt <[email protected]>

backup/moodle2/restore_stepslib.php

@@ -5440,6 +5440,25 @@ class restore_move_module_questions_categories extends restore_execution_step {
                     ];
                     $params += $categoryidparams;
                     $DB->execute($sqlupdate, $params);
+
+                    // As explained in {@see restore_quiz_activity_structure_step::process_quiz_question_legacy_instance()}
+                    // question_set_references relating to random questions restored from old backups,
+                    // which pick from context_module question_categores, will have been restored with the wrong questioncontextid.
+                    // So, now, we need to find those, and updated the questioncontextid.
+                    // We can only find them by picking apart the filter conditions, and seeign which categories they refer to.
+
+                    // We need to check all the question_set_references belonging to this context_module.
+                    $references = $DB->get_records('question_set_references', ['usingcontextid' => $newcontext->newitemid]);
+                    foreach ($references as $reference) {
+                        $filtercondition = json_decode($reference->filtercondition);
+                        if (!empty($filtercondition->questioncategoryid) &&
+                                in_array($filtercondition->questioncategoryid, $categoryids)) {
+                            // This is one of ours, update the questionscontextid.
+                            $DB->set_field('question_set_references',
+                                'questionscontextid', $newcontext->newitemid,
+                                ['id' => $reference->id]);
+                        }
+                    }
                 }
 
                 // Now set the parent id for the question categories that were in the top category in the course context
@@ -6245,6 +6264,11 @@ trait restore_question_set_reference_data_trait {
 
         if ($context = $this->get_mappingid('context', $data->questionscontextid)) {
             $data->questionscontextid = $context;
+        } else {
+            $this->log('question_set_reference with old id ' . $data->id .
+                ' referenced question context ' . $data->questionscontextid .
+                ' which was not included in the backup. Therefore, this has been ' .
+                ' restored with the old questionscontextid.', backup::LOG_WARNING);
         }
 
         $filtercondition['cat'] = implode(',', [

mod/quiz/backup/moodle2/restore_quiz_stepslib.php

@@ -349,12 +349,17 @@ class restore_quiz_activity_structure_step extends restore_questions_activity_st
 
         if ($question->qtype === 'random') {
             // Set reference data.
-            $questionsetreference = new \stdClass();
+            $questionsetreference = new stdClass();
             $questionsetreference->usingcontextid = context_module::instance(get_coursemodule_from_instance(
                 "quiz", $module->id, $module->course)->id)->id;
             $questionsetreference->component = 'mod_quiz';
             $questionsetreference->questionarea = 'slot';
             $questionsetreference->itemid = $data->id;
+            // If, in the orginal quiz that was backed up, this random question was pointing to a
+            // category in the quiz question bank, then (for reasons explained in {@see restore_move_module_questions_categories})
+            // right now, $question->questioncontextid will incorrectly point to the course contextid.
+            // This will get fixed up later in restore_move_module_questions_categories
+            // as part of moving the question categories to the right place.
             $questionsetreference->questionscontextid = $question->questioncontextid;
             $filtercondition = new stdClass();
             $filtercondition->questioncategoryid = $question->category;

mod/quiz/tests/backup/restore_39_test.php

@@ -0,0 +1,81 @@
+<?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\backup;
+
+use advanced_testcase;
+use backup;
+use restore_controller;
+
+/**
+ * Test restoring 3.9 backups including random questions.
+ *
+ * @package   mod_quiz
+ * @copyright 2024 Tomo Tsuyuki <[email protected]>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @covers    \restore_move_module_questions_categories
+ */
+final class restore_39_test extends advanced_testcase {
+
+    public function test_restore_random_question_39(): void {
+        global $DB, $USER;
+
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        // The example Moodle 3.9 backup file used in this test is an activity-level backup of a quiz.
+        // So, the backup contains just the quiz-level question bank which contains:
+        // | - Question category: Top
+        // |   - Question category: Default for Test MDL-78902 quiz
+        // |     - Question: Test MDL-78902 T/F question
+        // |     - Question: Random (Default for Test MDL-78902 quiz)
+        // The quiz itself contains 1 question, the random question.
+        // So, during the restore, the quiz_slot needs to be updated to use a question_set_reference.
+        $backupfile = 'moodle_39_quiz_with_random_question_from_mod_context';
+
+        // Extract backup file.
+        $backupid = $backupfile;
+        $backuppath = make_backup_temp_directory($backupid);
+        get_file_packer('application/vnd.moodle.backup')->extract_to_pathname(
+            __DIR__ . "/../fixtures/$backupfile.mbz", $backuppath);
+
+        // Restore the quiz activity in the backup from Moodle 3.9 to a new course.
+        $coursecat = self::getDataGenerator()->create_category();
+        $course = self::getDataGenerator()->create_course(['category' => $coursecat->id]);
+        $rc = new restore_controller($backupid, $course->id, backup::INTERACTIVE_NO,
+            backup::MODE_GENERAL, $USER->id, backup::TARGET_EXISTING_ADDING);
+        $this->assertTrue($rc->execute_precheck());
+        $rc->execute_plan();
+        $rc->destroy();
+
+        // Get information about the quiz activity and confirm the references are correct.
+        $modinfo = get_fast_modinfo($course->id);
+        $quizzes = array_values($modinfo->get_instances_of('quiz'));
+        // Get contextid for the restored quiz activity.
+        $contextid = $quizzes[0]->context->id;
+        $qcats = $DB->get_records('question_categories', ['contextid' => $contextid], 'parent');
+        // Confirm there are 2 question categories for the restored quiz activity.
+        $this->assertEquals(['top', 'Default for Test MDL-78902 quiz'], array_column($qcats, 'name'));
+        // Get question_set_references records for the restored quiz activity.
+        $references = $DB->get_records('question_set_references', ['usingcontextid' => $contextid]);
+        foreach ($references as $reference) {
+            $filtercondition = json_decode($reference->filtercondition);
+            // Confirm the questionscontextid is set correctly, which is from filter question category id.
+            $this->assertEquals($reference->questionscontextid,
+                $qcats[$filtercondition->questioncategoryid]->contextid);
+        }
+    }
+}