From 9c3e3a904be73b0d78aab6ba8a63d4dbb0862b72 Mon Sep 17 00:00:00 2001
From: Peter <peter@moodle.com>
Date: Mon, 17 Jun 2019 11:57:02 +0800
Subject: [PATCH] MDL-65469 mod_forum: Use the formchange checker initializer

---
 mod/forum/post.php | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/mod/forum/post.php b/mod/forum/post.php
index ec2fa052275..0cf58cd62de 100644
--- a/mod/forum/post.php
+++ b/mod/forum/post.php
@@ -35,6 +35,8 @@ $name    = optional_param('name', '', PARAM_CLEAN);
 $confirm = optional_param('confirm', 0, PARAM_INT);
 $groupid = optional_param('groupid', null, PARAM_INT);
 $subject = optional_param('subject', '', PARAM_TEXT);
+
+// Values posted via the inpage reply form.
 $prefilledpost = optional_param('post', '', PARAM_TEXT);
 $prefilledpostformat = optional_param('postformat', FORMAT_MOODLE, PARAM_INT);
 $prefilledprivatereply = optional_param('privatereply', false, PARAM_BOOL);
@@ -778,6 +780,25 @@ $mformpost->set_data(
     (isset($discussion->id) ? array('discussion' => $discussion->id) : array())
 );
 
+// If we are being redirected via a no_submit_button press OR if the message is being prefilled.
+// then set the initial 'dirty' state.
+// - A prefilled post will exist when being redirected from the inpage reply form.
+// - A no_submit_button press occurs when being redirected from the inpage add new discussion post form.
+$dirty = $prefilledpost ? true : false;
+if ($mformpost->no_submit_button_pressed()) {
+    $data = $mformpost->get_submitted_data();
+
+    // If a no submit button has been pressed but the default values haven't been then reset the form change.
+    if (!$dirty && !empty(trim($data->message['text']))) {
+        $dirty = true;
+    }
+
+    if (!$dirty && !empty(trim($data->message['message']))) {
+        $dirty = true;
+    }
+}
+$mformpost->set_initial_dirty_state($dirty);
+
 if ($mformpost->is_cancelled()) {
     if (!isset($discussion->id) || $forum->type === 'single') {
         // Single forums don't have a discussion page.