Fix replying to a commit discussion displayed in the context of an MR

2 files changed, 7 insertions, 1 deletions

diff --git a/app/helpers/notes_helper.rb b/app/helpers/notes_helper.rb
index 375110b77e2..3d4802290b5 100644
--- a/app/helpers/notes_helper.rb
+++ b/app/helpers/notes_helper.rb
@@ -50,7 +50,7 @@ module NotesHelper
   def link_to_reply_discussion(discussion, line_type = nil)
     return unless current_user
 
-    data = { discussion_id: discussion.id, line_type: line_type }
+    data = { discussion_id: discussion.reply_id, line_type: line_type }
 
     button_tag 'Reply...', class: 'btn btn-text-field js-discussion-reply-button',
                            data: data, title: 'Add a reply'
diff --git a/app/models/discussion.rb b/app/models/discussion.rb
index 9b32d573387..d1cec7613af 100644
--- a/app/models/discussion.rb
+++ b/app/models/discussion.rb
@@ -85,6 +85,12 @@ class Discussion
     first_note.discussion_id(context_noteable)
   end
 
+  def reply_id
+    # To reply to this discussion, we need the actual discussion_id from the database,
+    # not the potentially overwritten one based on the noteable.
+    first_note.discussion_id
+  end
+
   alias_method :to_param, :id
 
   def diff_discussion?