From 5990158a6fc3d8f053b293a32fc427d3bfa2d2b4 Mon Sep 17 00:00:00 2001
From: Tim Hunt <T.J.Hunt@open.ac.uk>
Date: Mon, 23 May 2022 17:46:12 +0100
Subject: [PATCH] MDL-74752 qtypes gapselect & ddwtos: implement regrading
 hooks

---
 .../gapselect/lang/en/qtype_gapselect.php     |  2 ++
 question/type/gapselect/questionbase.php      | 19 ++++++++++++
 .../type/gapselect/tests/question_test.php    | 30 +++++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/question/type/gapselect/lang/en/qtype_gapselect.php b/question/type/gapselect/lang/en/qtype_gapselect.php
index 81b74549728..9d3647adb1c 100644
--- a/question/type/gapselect/lang/en/qtype_gapselect.php
+++ b/question/type/gapselect/lang/en/qtype_gapselect.php
@@ -45,6 +45,8 @@ $string['privacy:metadata'] = 'Select missing words question type plugin allows
 $string['privacy:preference:defaultmark'] = 'The default mark set for a given question.';
 $string['privacy:preference:penalty'] = 'The penalty for each incorrect try when questions are run using the \'Interactive with multiple tries\' or \'Adaptive mode\' behaviour.';
 $string['privacy:preference:shuffleanswers'] = 'Whether the answers should be automatically shuffled.';
+$string['regradeissuenumchoiceschanged'] = 'The number of choices in group {$a} changed.';
+$string['regradeissuenumgroupsschanged'] = 'The number of groups of choices has changed.';
 $string['shuffle'] = 'Shuffle';
 $string['tagsnotallowed'] = '{$a->tag} is not allowed. (Only {$a->allowed} are permitted.)';
 $string['tagsnotallowedatall'] = '{$a->tag} is not allowed. (No HTML is allowed here.)';
diff --git a/question/type/gapselect/questionbase.php b/question/type/gapselect/questionbase.php
index 0a93eb4561f..10595d011c1 100644
--- a/question/type/gapselect/questionbase.php
+++ b/question/type/gapselect/questionbase.php
@@ -112,6 +112,25 @@ abstract class qtype_gapselect_question_base extends question_graded_automatical
         }
     }
 
+    public function validate_can_regrade_with_other_version(question_definition $otherversion): ?string {
+        $basemessage = parent::validate_can_regrade_with_other_version($otherversion);
+        if ($basemessage) {
+            return $basemessage;
+        }
+
+        if (count($this->choices) != count($otherversion->choices)) {
+            return get_string('regradeissuenumgroupsschanged', 'qtype_gapselect');
+        }
+
+        foreach ($this->choices as $group => $choices) {
+            if (count($this->choices[$group]) != count($otherversion->choices[$group])) {
+                return get_string('regradeissuenumchoiceschanged', 'qtype_gapselect', $group);
+            }
+        }
+
+        return null;
+    }
+
     public function get_question_summary() {
         $question = $this->html_to_text($this->questiontext, $this->questiontextformat);
         $groups = array();
diff --git a/question/type/gapselect/tests/question_test.php b/question/type/gapselect/tests/question_test.php
index 450e3008c01..5aef925f250 100644
--- a/question/type/gapselect/tests/question_test.php
+++ b/question/type/gapselect/tests/question_test.php
@@ -34,6 +34,8 @@ require_once($CFG->dirroot . '/question/type/gapselect/tests/helper.php');
  * @package   qtype_gapselect
  * @copyright 2012 The Open University
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @covers \qtype_gapselect_question_base
+ * @covers \qtype_gapselect_question
  */
 class question_test extends \basic_testcase {
 
@@ -258,4 +260,32 @@ class question_test extends \basic_testcase {
         $options = $question->get_question_definition_for_external_rendering($qa, $displayoptions);
         $this->assertEquals(1, $options['shufflechoices']);
     }
+
+    public function test_validate_can_regrade_with_other_version_ok() {
+        $question = \test_question_maker::make_question('gapselect');
+
+        $newquestion = clone($question);
+
+        $this->assertNull($newquestion->validate_can_regrade_with_other_version($question));
+    }
+
+    public function test_validate_can_regrade_with_other_version_bad_groups() {
+        $question = \test_question_maker::make_question('gapselect');
+
+        $newquestion = clone($question);
+        unset($newquestion->choices[3]);
+
+        $this->assertEquals(get_string('regradeissuenumgroupsschanged', 'qtype_gapselect'),
+                $newquestion->validate_can_regrade_with_other_version($question));
+    }
+
+    public function test_validate_can_regrade_with_other_version_bad_choices() {
+        $question = \test_question_maker::make_question('gapselect');
+
+        $newquestion = clone($question);
+        unset($newquestion->choices[2][2]);
+
+        $this->assertEquals(get_string('regradeissuenumchoiceschanged', 'qtype_gapselect', 2),
+                $newquestion->validate_can_regrade_with_other_version($question));
+    }
 }