```ruby
# frozen_string_literal: true
class Course::Assessment::Submission::Answer::Programming::AnnotationsController < \
  Course::Assessment::Submission::Answer::Programming::Controller

  include Course::Discussion::PostsConcern

  def create
    @annotation.class.transaction do
      @post.title = @assessment.title
      if super && @annotation.save
        send_created_notification(@post)
      else
        render status: :bad_request
      end
    end
  end

  private

  def annotation_params
    params.require(:annotation).permit(:line)
  end

  def line_param
    line = params[:line]
    line ||= params.key?(:annotation) && annotation_params[:line]
    line
  end

  def discussion_topic
    @annotation.discussion_topic
  end

  def create_topic_subscription
    @discussion_topic.ensure_subscribed_by(current_user)
    # Ensure the student who wrote the code gets notified when someone comments on his code
    @discussion_topic.ensure_subscribed_by(@answer.submission.creator)

    # Ensure all group managers get a notification when someone adds a programming annotation
    # to the answer.
    answer_course_user = @answer.submission.course_user
    answer_course_user.my_managers.each do |manager|
      @discussion_topic.ensure_subscribed_by(manager.user)
    end
  end

  def send_created_notification(post)
    if current_course_user && !current_course_user.phantom?
      post.topic.actable.notify(post)
    end
  end
end
```

Modify controller action to only return status 400
user
```ruby
# frozen_string_literal: true
class Course::Assessment::Submission::Answer::Programming::AnnotationsController < \
  Course::Assessment::Submission::Answer::Programming::Controller

  include Course::Discussion::PostsConcern

  def create
    @annotation.class.transaction do
      @post.title = @assessment.title
      if super && @annotation.save
        send_created_notification(@post)
      else
        head :bad_request
      end
    end
  end

  private

  def annotation_params
    params.require(:annotation).permit(:line)
  end

  def line_param
    line = params[:line]
    line ||= params.key?(:annotation) && annotation_params[:line]
    line
  end

  def discussion_topic
    @annotation.discussion_topic
  end

  def create_topic_subscription
    @discussion_topic.ensure_subscribed_by(current_user)
    # Ensure the student who wrote the code gets notified when someone comments on his code
    @discussion_topic.ensure_subscribed_by(@answer.submission.creator)

    # Ensure all group managers get a notification when someone adds a programming annotation
    # to the answer.
    answer_course_user = @answer.submission.course_user
    answer_course_user.my_managers.each do |manager|
      @discussion_topic.ensure_subscribed_by(manager.user)
    end
  end

  def send_created_notification(post)
    if current_course_user && !current_course_user.phantom?
      post.topic.actable.notify(post)
    end
  end
end
```
assistant