gitlab-org--gitlab-foss/app/models/individual_note_discussion.rb

# A discussion to wrap a single `Note` note on the root of an issue, merge request,
# commit, or snippet, that is not displayed as a discussion.
#
# A discussion of this type is never resolvable.
class IndividualNoteDiscussion < Discussion
  def self.note_class
    Note
  end

  def individual_note?
    true
  end

  def reply_attributes
    super.tap { |attrs| attrs.delete(:discussion_id) }
  end
end