[0.9.12] Need to add handle the invalid request

Need to add handle the invalid request
The bug report below shows the necessary cases

begin
  require 'bundler/inline'
  require 'bundler'
rescue LoadError => e
  STDERR.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true, ui: ENV['SILENT'] ? Bundler::UI::Silent.new : Bundler::UI::Shell.new) do
  source 'https://rubygems.org'

  gem 'rails', require: false
  gem 'sqlite3', platform: :mri
  gem 'byebug'

  gem 'activerecord-jdbcsqlite3-adapter',
      git: 'https://github.com/jruby/activerecord-jdbc-adapter',
      platform: :jruby

  if ENV['JSONAPI_RESOURCES_PATH']
    gem 'jsonapi-resources', path: ENV['JSONAPI_RESOURCES_PATH'], require: false
  else
    gem 'jsonapi-resources', git: 'https://github.com/cerebris/jsonapi-resources', require: false
  end

end

# prepare active_record database
require 'active_record'

class NullLogger < Logger
  def initialize(*_args) end

  def add(*_args, &_block) end
end

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = ENV['SILENT'] ? NullLogger.new : Logger.new(STDOUT)
ActiveRecord::Migration.verbose = !ENV['SILENT']

ActiveRecord::Schema.define do
  # Add your schema here
  create_table :authors, force: true do |t|
    t.string :name
  end

  create_table :books, force: true do |t|
    t.string :text
    t.references :author
  end
end

# create models
class Author < ActiveRecord::Base
  has_many :books
end

class Comment < ActiveRecord::Base
  belongs_to :author
end

# prepare rails app
require 'action_controller/railtie'
# require 'action_view/railtie'
require 'jsonapi-resources'

class ApplicationController < ActionController::Base
end

# prepare jsonapi resources and controllers
class AuthorsController < ApplicationController
  include JSONAPI::ActsAsResourceController
end

class BooksController < ApplicationController
  include JSONAPI::ActsAsResourceController
end

class AuthorResource < JSONAPI::Resource
  attribute :name
  has_many :books, polymorphic: true, class_name: 'Book'
end

class BookResource < JSONAPI::Resource
  attribute :text
end

class TestApp < Rails::Application
  config.root = File.dirname(__FILE__)
  config.logger = ENV['SILENT'] ? NullLogger.new : Logger.new(STDOUT)
  Rails.logger = config.logger

  secrets.secret_token = 'secret_token'
  secrets.secret_key_base = 'secret_key_base'

  config.eager_load = false
end

Rails.application.configure do
  config.hosts << 'example.org'
end

# initialize app
Rails.application.initialize!

JSONAPI.configure do |config|
  config.json_key_format = :underscored_key
  config.route_format = :underscored_key
end

# draw routes
Rails.application.routes.draw do
  jsonapi_resources :authors, only: [:show, :update]
end

# prepare tests
require 'minitest/autorun'
require 'rack/test'

# Replace this with the code necessary to make your test fail.
class BugTest < Minitest::Test
  include Rack::Test::Methods

  def json_api_headers
    { 'Accept' => JSONAPI::MEDIA_TYPE, 'CONTENT_TYPE' => JSONAPI::MEDIA_TYPE }
  end

  def test_relationships_as_array
    author = Author.create!
    json_request = {
      data: {
        id: author.id.to_s,
        type: 'authors',
        relationships: []
      }
    }
    patch "/authors/#{author.id}", json_request.to_json, json_api_headers
    assert last_response.bad_request?
  end

  def test_relationships_as_nil
    author = Author.create!
    json_request = {
      data: {
        id: author.id.to_s,
        type: 'authors',
        relationships: nil
      }
    }
    patch "/authors/#{author.id}", json_request.to_json, json_api_headers
    assert last_response.bad_request?
  end

  def test_attributes_as_nil
    author = Author.create!
    json_request = {
      data: {
        id: author.id.to_s,
        type: 'authors',
        attributes: nil
      }
    }
    patch "/authors/#{author.id}", json_request.to_json, json_api_headers
    assert last_response.bad_request?
  end

  def test_relationship_name_in_attributes
    author = Author.create!
    json_request = {
      data: {
        id: author.id.to_s,
        type: 'authors',
        attributes: {
          books: []
        }
      }
    }
    patch "/authors/#{author.id}", json_request.to_json, json_api_headers
    assert last_response.bad_request?
  end

  private

  def app
    Rails.application
  end
end

Solution:
Need update method verify_permitted_params

jsonapi-resources/lib/jsonapi/request_parser.rb

Line 583 in dc96280

def verify_permitted_params(params, allowed_fields)

def verify_permitted_params(params, allowed_fields)
  formatted_allowed_fields = allowed_fields.collect { |field| format_key(field).to_sym }
  params_not_allowed = []

  params.each do |key, value|
    case key.to_s
    when 'relationships'
    raise JSONAPI::Exceptions::TypeMismatch.new(nil) unless value.is_a?(ActionController::Parameters) # ADDED THIS LINE

      value.keys.each do |links_key|
        unless formatted_allowed_fields.include?(links_key.to_sym)
          if JSONAPI.configuration.raise_if_parameters_not_allowed
            fail JSONAPI::Exceptions::ParameterNotAllowed.new(links_key)
          else
            params_not_allowed.push(links_key)
            value.delete links_key
          end
        end
      end
    when 'attributes'
    raise JSONAPI::Exceptions::TypeMismatch.new(nil) unless value.is_a?(ActionController::Parameters) # ADDED THIS LINE
    
    attributes = formatted_allowed_fields - resource_klass._relationships.keys # ADDED THIS LINE
      value.each do |attr_key, attr_value|
        unless formatted_allowed_fields.include?(attr_key.to_sym)
          if JSONAPI.configuration.raise_if_parameters_not_allowed
            fail JSONAPI::Exceptions::ParameterNotAllowed.new(attr_key)
          else
            params_not_allowed.push(attr_key)
            value.delete attr_key
          end
        end
      end
    when 'type'
    when 'id'
      unless formatted_allowed_fields.include?(:id)
        if JSONAPI.configuration.raise_if_parameters_not_allowed
          fail JSONAPI::Exceptions::ParameterNotAllowed.new(:id)
        else
          params_not_allowed.push(:id)
          params.delete :id
        end
      end
    else
      if JSONAPI.configuration.raise_if_parameters_not_allowed
        fail JSONAPI::Exceptions::ParameterNotAllowed.new(key)
      else
        params_not_allowed.push(key)
        params.delete key
      end
    end
  end

  if params_not_allowed.length > 0
    params_not_allowed_warnings = params_not_allowed.map do |param|
      JSONAPI::Warning.new(code: JSONAPI::PARAM_NOT_ALLOWED,
                           title: 'Param not allowed',
                           detail: "#{param} is not allowed.")
    end
    self.warnings.concat(params_not_allowed_warnings)
  end
end