fix: Re-use resource class for remote sideloads to avoid memory leak (#421)

Author: PChambino

lib/graphiti.rb

@@ -137,7 +137,6 @@ def self.setup!
 require "graphiti/request_validator"
 require "graphiti/request_validators/validator"
 require "graphiti/request_validators/update_validator"
-require "graphiti/query"
 require "graphiti/scope"
 require "graphiti/deserializer"
 require "graphiti/renderer"
@@ -176,6 +175,7 @@ def self.setup!
 require "graphiti/extensions/boolean_attribute"
 require "graphiti/extensions/temp_id"
 require "graphiti/serializer"
+require "graphiti/query"
 require "graphiti/debugger"
 
 if defined?(ActiveRecord)

lib/graphiti/query.rb

@@ -76,11 +76,14 @@ def sideload_hash
       end
     end
 
+    class RemoteSideloadResource < ::Graphiti::Resource
+      self.remote = "_remote_sideload_".freeze
+      self.abstract_class = true # exclude from schema
+    end
+
     def resource_for_sideload(sideload)
       if @resource.remote?
-        Class.new(Graphiti::Resource) {
-          self.remote = "_remote_sideload_"
-        }.new
+        RemoteSideloadResource.new
       else
         sideload.resource
       end

spec/query_spec.rb

@@ -11,6 +11,7 @@
   before do
     employee_resource.has_many :positions,
       resource: position_resource
+    employee_resource.belongs_to :remote, remote: true
     position_resource.belongs_to :department,
       resource: department_resource
     employee_resource.attribute :name, :string
@@ -986,11 +987,29 @@
     end
 
     describe "sideloads" do
-      before { params[:include] = "positions" }
       subject(:sideloads) { instance.sideloads }
 
-      it "does not cascate the action" do
-        expect(sideloads.values.map(&:action)).to eq([:all])
+      context "when including an has_many resource" do
+        before { params[:include] = "positions" }
+
+        it "does not cascate the action" do
+          expect(sideloads.values.map(&:action)).to eq([:all])
+        end
+      end
+
+      context "when including a resource from a remote resource" do
+        before { params[:include] = "remote.resource" }
+
+        let(:sideloads_of_another_query) { described_class.new(resource, params).sideloads }
+
+        def resource_class_of_remote_sideload(sideloads)
+          sideloads.fetch(:remote).sideloads.fetch(:resource).resource.class
+        end
+
+        it "re-uses resource class across multiple queries (avoid memory leak)" do
+          expect(resource_class_of_remote_sideload(sideloads))
+            .to eq(resource_class_of_remote_sideload(sideloads_of_another_query))
+        end
       end
     end
   end