Add Rails 8.1 compatibility improvements

This commit addresses several Rails 8.1 compatibility issues:

1. **CSV gem dependency**: Added 'csv' gem to Gemfile for Rails 8.1+
   (removed from standard library). Required by acts_as_resource_controller.rb.

2. **HTTP status code compatibility**: Updated :unprocessable_entity to
   use conditional :unprocessable_content for Rails 8.0+ to avoid deprecation
   warnings while maintaining backward compatibility with earlier Rails versions.
   - Added unprocessable_status helper in JSONAPI::Exceptions::Error
   - Updated ValidationErrors and SaveFailed exceptions
   - Updated test assertions in controller_test.rb and test helpers

3. **Database adapter improvements**: Simplified db_true helper in
   join_manager_test.rb to use ActiveRecord::Base.connection.quoted_true
   for database-agnostic boolean value handling.

These changes maintain full backward compatibility with Rails 6.1, 7.0,
and 7.1 while preparing for Rails 8.0+.

Based on upstream PR: https://github.com/cerebris/jsonapi-resources/pull/1485

Co-Authored-By: Cassie Simpson <simps614@umn.edu>

Author: takaokouji

Gemfile

@@ -28,6 +28,7 @@ when 'master'
   gem 'arel', { git: 'https://github.com/rails/arel.git' }
 when 'default'
   gem 'railties', '>= 6.0'
+  gem 'csv'  # Required by Rails 8.1+ (removed from standard library)
 else
   gem 'railties', "~> #{version}"
 end

lib/jsonapi/exceptions.rb

@@ -18,6 +18,18 @@ def errors
         raise NotImplementedError, "Subclass of Error must implement errors method"
         # :nocov:
       end
+
+      private
+
+      # Rails 8.0+ deprecated :unprocessable_entity in favor of :unprocessable_content
+      # This helper maintains backward compatibility with earlier Rails versions
+      def unprocessable_status
+        if Rails::VERSION::MAJOR >= 8
+          :unprocessable_content
+        else
+          :unprocessable_entity
+        end
+      end
     end
 
     class Errors < Error
@@ -498,7 +510,7 @@ def errors
 
       def json_api_error(attr_key, message)
         create_error_object(code: JSONAPI::VALIDATION_ERROR,
-                            status: :unprocessable_entity,
+                            status: unprocessable_status,
                             title: message,
                             detail: detail(attr_key, message),
                             source: { pointer: pointer(attr_key) },
@@ -532,7 +544,7 @@ def general_error?(attr_key)
     class SaveFailed < Error
       def errors
         [create_error_object(code: JSONAPI::SAVE_FAILED,
-                             status: :unprocessable_entity,
+                             status: unprocessable_status,
                              title: I18n.translate('jsonapi-resources.exceptions.save_failed.title',
                                                    default: 'Save failed or was cancelled'),
                              detail: I18n.translate('jsonapi-resources.exceptions.save_failed.detail',

test/controllers/controller_test.rb

@@ -761,7 +761,7 @@ def test_create_link_to_missing_object
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
     # TODO: check if this validation is working
     assert_match /author - can't be blank/, response.body
     assert_nil response.location
@@ -864,7 +864,7 @@ def test_create_with_invalid_data
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
 
     assert_equal "/data/relationships/author", json_response['errors'][0]['source']['pointer']
     assert_equal "can't be blank", json_response['errors'][0]['title']
@@ -2019,7 +2019,7 @@ def test_delete_with_validation_error_base
 
     assert_equal "can't destroy me", json_response['errors'][0]['title']
     assert_equal "/data", json_response['errors'][0]['source']['pointer']
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
   end
 
   def test_delete_with_validation_error_attr
@@ -2028,7 +2028,7 @@ def test_delete_with_validation_error_attr
 
     assert_equal "is locked", json_response['errors'][0]['title']
     assert_equal "/data/attributes/title", json_response['errors'][0]['source']['pointer']
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
   end
 
   def test_delete_single
@@ -2631,7 +2631,7 @@ def test_create_validations_missing_attribute
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
     assert_equal 2, json_response['errors'].size
     assert_equal JSONAPI::VALIDATION_ERROR, json_response['errors'][0]['code']
     assert_equal JSONAPI::VALIDATION_ERROR, json_response['errors'][1]['code']
@@ -2653,7 +2653,7 @@ def test_update_validations_missing_attribute
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
     assert_equal 1, json_response['errors'].size
     assert_equal JSONAPI::VALIDATION_ERROR, json_response['errors'][0]['code']
     assert_match /name - can't be blank/, response.body
@@ -3183,7 +3183,7 @@ def test_create_with_invalid_data
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
 
     assert_equal "/data/attributes/spouse-name", json_response['errors'][0]['source']['pointer']
     assert_equal "can't be blank", json_response['errors'][0]['title']
@@ -3781,7 +3781,7 @@ def test_save_model_callbacks_fail
         }
       }
 
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
     assert_match /Save failed or was cancelled/, json_response['errors'][0]['detail']
   end
 end
@@ -4079,7 +4079,7 @@ def test_delete_with_validation_error_base_on_resource
 
     assert_equal "can't destroy me", json_response['errors'][0]['title']
     assert_equal "/data/attributes/base", json_response['errors'][0]['source']['pointer']
-    assert_response :unprocessable_entity
+    assert_response unprocessable_status
   end
 end
 

test/helpers/functional_helpers.rb

@@ -55,5 +55,15 @@ module FunctionalHelpers
     def json_response
       JSON.parse(@response.body)
     end
+
+    # Rails 8.0+ deprecated :unprocessable_entity in favor of :unprocessable_content
+    # This helper maintains backward compatibility in tests
+    def unprocessable_status
+      if Rails::VERSION::MAJOR >= 8
+        :unprocessable_content
+      else
+        :unprocessable_entity
+      end
+    end
   end
 end

test/test_helper.rb

@@ -585,6 +585,16 @@ def assert_jsonapi_response(expected_status, msg = nil)
     assert_equal expected_status, status, msg
   end
 
+  # Rails 8.0+ deprecated :unprocessable_entity in favor of :unprocessable_content
+  # This helper maintains backward compatibility in tests
+  def unprocessable_status
+    if Rails::VERSION::MAJOR >= 8
+      :unprocessable_content
+    else
+      :unprocessable_entity
+    end
+  end
+
   def assert_jsonapi_get(url, msg = "GET response must be 200")
     get url, headers: { 'Accept' => JSONAPI::MEDIA_TYPE }
     assert_jsonapi_response 200, msg

test/unit/active_relation_resource_finder/join_manager_test.rb

@@ -4,19 +4,7 @@
 class JoinTreeTest < ActiveSupport::TestCase
 
   def db_true
-    case ActiveRecord::Base.connection.adapter_name
-      when 'SQLite'
-        if Rails::VERSION::MAJOR >= 8 && Rails::VERSION::MINOR >= 1
-          # Rails 8.1+ SQLite uses TRUE instead of 1
-          "TRUE"
-        elsif Rails::VERSION::MAJOR >= 6 || (Rails::VERSION::MAJOR >= 5 && ActiveRecord::VERSION::MINOR >= 2)
-          "1"
-        else
-          "'t'"
-        end
-      when 'PostgreSQL'
-        'TRUE'
-    end
+    ActiveRecord::Base.connection.quoted_true
   end
 
   def test_no_added_joins