class Doorkeeper::OAuth::AuthorizationCodeRequest

def validate_params
  @missing_param =
    if grant&.uses_pkce? && code_verifier.blank?
      :code_verifier
    elsif !confidential? && Doorkeeper.config.force_pkce? && code_verifier.blank?
      :code_verifier
    elsif redirect_uri.blank?
      :redirect_uri
    end
  @missing_param.nil?
end