From f533f30d3b3838f80bddd406d8c2b8411198b408 Mon Sep 17 00:00:00 2001
From: Paul Holden <paulh@moodle.com>
Date: Wed, 7 Sep 2022 16:53:06 +0100
Subject: [PATCH] MDL-29421 forms: return formatted frozen content for editor
 element.

This was partly addressed in 82d491ca, however formatted content and
embedded images were rendered incorrectly.
---
 public/course/edit_form.php                   |  2 -
 .../grade/grading/form/rubric/edit_form.php   |  3 +-
 public/lib/form/editor.php                    | 41 +++++++++++++-
 public/lib/form/tests/editor_test.php         | 54 +++++++++++++++++++
 4 files changed, 94 insertions(+), 6 deletions(-)
 create mode 100644 public/lib/form/tests/editor_test.php

diff --git a/public/course/edit_form.php b/public/course/edit_form.php
index 81679feb48b..4b33c3cacb0 100644
--- a/public/course/edit_form.php
+++ b/public/course/edit_form.php
@@ -217,8 +217,6 @@ class course_edit_form extends moodleform {
         }
 
         if (!empty($course->id) and !has_capability('moodle/course:changesummary', $coursecontext)) {
-            // Remove the description header it does not contain anything any more.
-            $mform->removeElement('descriptionhdr');
             $mform->hardFreeze($summaryfields);
         }
 
diff --git a/public/grade/grading/form/rubric/edit_form.php b/public/grade/grading/form/rubric/edit_form.php
index 5ba5c9fd238..07da99e39e9 100644
--- a/public/grade/grading/form/rubric/edit_form.php
+++ b/public/grade/grading/form/rubric/edit_form.php
@@ -177,9 +177,8 @@ class gradingform_rubric_editrubric extends moodleform {
         }
 
         // freeze form elements and pass the values in hidden fields
-        // TODO MDL-29421 description_editor does not freeze the normal way, uncomment below when fixed
         $form = $this->_form;
-        foreach (array('rubric', 'name'/*, 'description_editor'*/) as $fieldname) {
+        foreach (['rubric', 'name', 'description_editor'] as $fieldname) {
             $el =& $form->getElement($fieldname);
             $el->freeze();
             $el->setPersistantFreeze(true);
diff --git a/public/lib/form/editor.php b/public/lib/form/editor.php
index 8b178997322..5b85e8e0c43 100644
--- a/public/lib/form/editor.php
+++ b/public/lib/form/editor.php
@@ -41,7 +41,6 @@ require_once('templatable_form_element.php');
  * @category  form
  * @copyright 2009 Petr Skoda {@link http://skodak.org}
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- * @todo      MDL-29421 element Freezing
  * @todo      MDL-29426 ajax format conversion
  */
 class MoodleQuickForm_editor extends HTML_QuickForm_element implements templatable {
@@ -495,13 +494,51 @@ class MoodleQuickForm_editor extends HTML_QuickForm_element implements templatab
         return $context;
     }
 
+    /**
+     * Used by getFrozenHtml() to pass the element's value if _persistantFreeze is on
+     *
+     * @return string
+     */
+    public function _getPersistantData() {
+        if (!$this->_persistantFreeze) {
+            return '';
+        } else {
+            $id = $this->getAttribute('id');
+            if (isset($id)) {
+                // Id of persistant input is different then the actual input.
+                $id = ['id' => $id . '_persistant'];
+            } else {
+                $id = [];
+            }
+
+            $str = '';
+            foreach ($this->getValue() as $key => $value) {
+                $str .= html_writer::empty_tag('input', [
+                    'type' => 'hidden',
+                    'name' => $this->getName() . "[{$key}]",
+                    'value' => $value,
+                ] + $id);
+            }
+            return $str;
+        }
+    }
+
     /**
      * Returns the formatted value. The return from parent class is not acceptable.
      *
      * @return string
      */
     public function getFrozenHtml(): string {
-        return format_text($this->get_text(), $this->getFormat()) . $this->_getPersistantData();
+        global $CFG;
+
+        ['text' => $text, 'format' => $format] = $this->getValue();
+
+        // In post-formatted content, draftfiles are never expected to exist. However, in this case we do need to show
+        // embedded draft files, because they are expected to exist in the editor element.
+        $content = format_text($text, $format, ['context' => $this->_options['context'], 'overflowdiv' => true]);
+        $content = str_replace("\"$CFG->wwwroot/brokenfile.php#", "\"$CFG->wwwroot/draftfile.php", $content);
+
+        return $content . $this->_getPersistantData();
     }
 
     /**
diff --git a/public/lib/form/tests/editor_test.php b/public/lib/form/tests/editor_test.php
new file mode 100644
index 00000000000..3805118006e
--- /dev/null
+++ b/public/lib/form/tests/editor_test.php
@@ -0,0 +1,54 @@
+<?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 core_form;
+
+use advanced_testcase;
+use MoodleQuickForm_editor;
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once("{$CFG->libdir}/form/editor.php");
+
+/**
+ * Tests for the editor form element
+ *
+ * @package    core_form
+ * @covers     \MoodleQuickForm_editor
+ * @copyright  2026 Paul Holden <paulh@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+final class editor_test extends advanced_testcase {
+    /**
+     * Test retrieving frozen HTML
+     */
+    public function test_get_frozen_html(): void {
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        // Ensure "URL" filter is active.
+        filter_set_global_state('urltolink', TEXTFILTER_ON);
+
+        $element = new MoodleQuickForm_editor('description_editor', 'Description');
+        $element->setValue(['text' => 'http://example.com', 'format' => FORMAT_HTML]);
+
+        $this->assertStringContainsString(
+            '<a href="http://example.com" class="_blanktarget">http://example.com</a>',
+            $element->getFrozenHtml(),
+        );
+    }
+}