Introduce Resource.retrieve_records

Allows the processor to retrieve records without further filtering,
which will have taken place earlier in the `find_fragments` and
`find_related_fragments`. This fixes issues where `records` has been
overridden and interferes with getting included
records (and already filtered by the find fragment step).

Author: lgebhardt

lib/jsonapi/processor.rb

@@ -578,14 +578,10 @@ def populate_resource_set(resource_set, serializer, find_options)
 
         # fill in the missed resources, it there are any
         unless missed_ids.empty?
-          filters = {resource_klass._primary_key => missed_ids}
-          find_opts = {
-              context: context,
-              fields: find_options[:fields] }
+          missed_records = resource_klass.retrieve_records(missed_ids, find_options)
+          missed_resources = resource_klass.resources_for(missed_records, context)
 
-          found_resources = resource_klass.find(filters, find_opts)
-
-          found_resources.each do |resource|
+          missed_resources.each do |resource|
             relationship_data = resource_set[resource_klass][resource.id][:relationships]
 
             if resource_klass.caching?

lib/jsonapi/resource.rb

@@ -732,6 +732,10 @@ def records(options = {})
         _model_class.all
       end
 
+      def retrieve_records(ids, options = {})
+        _model_class.where(_primary_key => ids)
+      end
+
       def resources_for(records, context)
         records.collect do |record|
           resource_for(record, context)

test/fixtures/active_record.rb

@@ -1450,6 +1450,10 @@ def find_records_by_keys(keys, options = {})
       end
       breeds
     end
+
+    def retrieve_records(ids, options = {})
+      find_records_by_keys(ids, options)
+    end
   end
 end