MDL-78902 backup: fix restore random question.

backup/moodle2/restore_stepslib.php

@@ -5388,6 +5388,7 @@ protected function define_execution() {
                 $top = question_get_top_category($newcontext->newitemid, true);
                 $oldtopid = 0;
                 $categoryids = [];
+                $questioncategories = [];
                 foreach ($modulecats as $modulecat) {
                     // Before 3.5, question categories could be created at top level.
                     // From 3.5 onwards, all question categories should be a child of a special category called the "top" category.
@@ -5396,14 +5397,22 @@ protected function define_execution() {
                         $oldtopid = $modulecat->newitemid;
                         $modulecat->newitemid = $top->id;
                     } else {
-                        $cat = new stdClass();
-                        $cat->id = $modulecat->newitemid;
-                        $cat->contextid = $newcontext->newitemid;
-                        if (empty($info->parent)) {
-                            $cat->parent = $top->id;
+                        $catid = $modulecat->newitemid;
+                        $cat = $DB->get_record('question_categories', ['id' => $catid]);
+                        if ($cat) {
+                            $oldcontextid = $cat->contextid;
+                            $cat->contextid = $newcontext->newitemid;
+                            if (empty($info->parent)) {
+                                $cat->parent = $top->id;
+                            }
+                            $DB->update_record('question_categories', $cat);
+                            $questioncategories[$catid] = [
+                                'id' => $catid,
+                                'oldcontextid' => $oldcontextid,
+                                'newcontextid' => $newcontext->newitemid,
+                            ];
                         }
-                        $DB->update_record('question_categories', $cat);
-                        $categoryids[] = (int)$cat->id;
+                        $categoryids[] = (int)$catid;
                     }
 
                     // And set new contextid (and maybe update newitemid) also in question_category mapping (will be
@@ -5434,6 +5443,19 @@ protected function define_execution() {
                     ];
                     $params += $categoryidparams;
                     $DB->execute($sqlupdate, $params);
+
+                    // Update questionscontextid in question_set_references.
+                    foreach ($questioncategories as $questioncategory) {
+                        $references = $DB->get_records('question_set_references', ['questionscontextid' => $oldcontextid]);
+                        foreach ($references as $reference) {
+                            $filtercondition = json_decode($reference->filtercondition);
+                            if (!empty($filtercondition->questioncategoryid)
+                                && $filtercondition->questioncategoryid == $questioncategory['id']) {
+                                $reference->questionscontextid = $questioncategory['newcontextid'];
+                                $DB->update_record('question_set_references', $reference);
+                            }
+                        }
+                    }
                 }
 
                 // Now set the parent id for the question categories that were in the top category in the course context

backup/moodle2/tests/behat/restore_random_question.feature

@@ -0,0 +1,19 @@
+@core @core_backup
+Feature: Restore random question
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category |
+      | Course 1 | C1        | 0        |
+
+  @javascript @_file_upload
+  Scenario: Restore the quiz from 3.9 containing random questions
+    Given I am on the "Course 1" "restore" page logged in as "admin"
+    And I press "Manage course backups"
+    And I upload "backup/moodle2/tests/fixtures/test_random_question_39.mbz" file to "Files" filemanager
+    And I press "Save changes"
+    And I restore "test_random_question_39.mbz" backup into "Course 1" course using this options:
+    When I am on the "Test MDL-78902 quiz" "mod_quiz > edit" page logged in as admin
+    Then I should see "See questions"
+    And I click on "See questions" "link"
+    Then I should see "Test MDL-78902 T/F question"