Subjects make sense for new discussions only, not in replies.

classes/post/post_control.php

@@ -265,12 +265,6 @@ private function build_prepost_reply(int $replypostid): void {
             throw new moodle_exception('activityiscurrentlyhidden');
         }
 
-        // Append 'RE: ' to the discussions subject.
-        $strre = get_string('re', 'moodleoverflow');
-        if (!(str_starts_with($this->prepost->subject, $strre))) {
-            $this->prepost->subject = $strre . ' ' . $this->prepost->subject;
-        }
-
         // Unset where the user is coming from.
         // Allows to calculate the correct return url later.
         unset($SESSION->fromdiscussion);

classes/post_form.php

@@ -51,11 +51,13 @@ public function definition() {
         // Fill in the data depending on page params later using set_data.
         $modform->addElement('header', 'general', '');
 
-        // The subject.
-        $modform->addElement('text', 'subject', get_string('subject', 'moodleoverflow'), 'size="48"');
-        $modform->setType('subject', PARAM_TEXT);
-        $modform->addRule('subject', get_string('required'), 'required', null, 'client');
-        $modform->addRule('subject', get_string('maximumchars', '', 255), 'maxlength', 255, 'client');
+        // Show the subject only when this is a new post.
+        if (empty($post->parentid)) {
+            $modform->addElement('text', 'subject', get_string('subject', 'moodleoverflow'), 'size="48"');
+            $modform->setType('subject', PARAM_TEXT);
+            $modform->addRule('subject', get_string('required'), 'required', null, 'client');
+            $modform->addRule('subject', get_string('maximumchars', '', 255), 'maxlength', 255, 'client');
+        }
 
         // The message.
         $modform->addElement(
@@ -125,7 +127,8 @@ public function validation($data, $files) {
         if (empty($data['message']['text'])) {
             $errors['message'] = get_string('erroremptymessage', 'moodleoverflow');
         }
-        if (empty($data['subject'])) {
+        // Subject must not be empty when creating a new discussion only.
+        if (empty($data['subject']) && empty($this->_customdata['post']->parentid)) {
             $errors['subject'] = get_string('erroremptysubject', 'moodleoverflow');
         }
 

tests/behat/delete_file.feature

@@ -22,7 +22,6 @@ Feature: Delete attachments
     And I follow "Forum post 1"
     And I click on "Answer" "link"
     And I set the following fields to these values:
-      | Subject | A reply post |
       | Message | This is the message of the answer post |
     And I upload "mod/moodleoverflow/tests/fixtures/NH.jpg" file to "Attachment" filemanager
     And I press "Post to forum"

tests/behat/delete_post.feature

@@ -27,4 +27,4 @@ Feature: Teachers and students can delete posts
     And I log out
     And I navigate as "student1" to "Course 1" "Moodleoverflow 1" "Discussion 1"
     And I try to delete moodleoverflow post "Answer from student"
-    Then I should see "You are not allowed to delete this post because it already has replies."
+    Then I should see "You are not allowed to delete this post because it already has replies."

tests/behat/limitedanswer.feature

@@ -27,7 +27,6 @@ Feature: Moodleoverflows can start in a limited answer mode, where answers from
     And I click on "Answer" "text"
     Then I should see "Your reply"
     And I set the following fields to these values:
-      | Subject | Re: Forum post 1 |
       | Message | This is the answer message |
     And I press "Post to forum"
     Then I should "" see the elements:

tests/behat/reply_post.feature

@@ -9,4 +9,6 @@ Feature: Replying to posts in a moodleoverflow
     When I click on "#moodleoverflow_showpost" "css_element"
     Then I should see "Message from teacher"
     When I click on "#moodleoverflow_showpost" "css_element"
-    Then I should not see "Message from teacher"
+    Then I should not see "Message from teacher"
+    And I should not see "Subject"
+    And I should see "Message"

tests/behat/track_read_posts.feature

@@ -80,4 +80,3 @@ Feature: A teacher can set one of 3 possible options for tracking read moodleove
     When I click on "Mark all posts as read" "link"
     And I am on "Course 1" course homepage
     Then I should not see "2 unread post"
-