Simplify ActiveModel::ErrorSerializer

We're only running CI for Rails 6.1+ now, and we can now rely on a
stable API for ActiveModel::Errors.

Author: mamhoff

lib/jsonapi/active_model_error_serializer.rb

@@ -12,35 +12,15 @@ class ActiveModelErrorSerializer < ErrorSerializer
     end
 
     attribute :code do |object|
-      _, error_hash = object
-      code = error_hash[:error] unless error_hash[:error].is_a?(Hash)
-      code ||= error_hash[:message] || :invalid
-      # `parameterize` separator arguments are different on Rails 4 vs 5...
-      code.to_s.delete("''").parameterize.tr('-', '_')
+      object.type.to_s.delete("''").parameterize.tr('-', '_')
     end
 
-    attribute :detail do |object, params|
-      error_key, error_hash = object
-      errors_object = params[:model].errors
-
-      # Rails 4 provides just the message.
-      if error_hash[:error].present? && error_hash[:error].is_a?(Hash)
-        message = errors_object.generate_message(
-          error_key, nil, error_hash[:error]
-        )
-      elsif error_hash[:error].present?
-        message = errors_object.generate_message(
-          error_key, error_hash[:error], error_hash
-        )
-      else
-        message = error_hash[:message]
-      end
-
-      errors_object.full_message(error_key, message)
+    attribute :detail do |object, _params|
+      object.full_message
     end
 
     attribute :source do |object, params|
-      error_key, _ = object
+      error_key = object.attribute
       model_serializer = params[:model_serializer]
       attrs = (model_serializer.attributes_to_serialize || {}).keys
       rels = (model_serializer.relationships_to_serialize || {}).keys

lib/jsonapi/rails.rb

@@ -46,7 +46,6 @@ def self.add_errors_renderer!
           JSONAPI::ErrorSerializer.new(resource, options)
         ) unless resource.is_a?(ActiveModel::Errors)
 
-        errors = []
         model = resource.instance_variable_get(:@base)
 
         if respond_to?(:jsonapi_serializer_class, true)
@@ -55,31 +54,9 @@ def self.add_errors_renderer!
           model_serializer = JSONAPI::Rails.serializer_class(model, false)
         end
 
-        details = {}
-        if ::Rails.gem_version >= Gem::Version.new('6.1')
-          resource.each do |error|
-            attr = error.attribute
-            details[attr] ||= []
-            details[attr] << error.detail.merge(message: error.message)
-          end
-        elsif resource.respond_to?(:details)
-          details = resource.details
-        else
-          details = resource.messages
-        end
-
-        details.each do |error_key, error_hashes|
-          error_hashes.each do |error_hash|
-            # Rails 4 provides just the message.
-            error_hash = { message: error_hash } unless error_hash.is_a?(Hash)
-
-            errors << [ error_key, error_hash ]
-          end
-        end
-
         JSONAPI::Rails.serializer_to_json(
           JSONAPI::ActiveModelErrorSerializer.new(
-            errors, params: { model: model, model_serializer: model_serializer }
+            resource.errors, params: { model: model, model_serializer: model_serializer }
           )
         )
       end