Fix issue with through associations

Fix #163

lib/chrono_model.rb

@@ -69,6 +69,10 @@ def chrono?
   prepend ChronoModel::Patches::Preloader::Association
 end
 
+ActiveRecord::Associations::Preloader::ThroughAssociation.instance_eval do
+  prepend ChronoModel::Patches::Preloader::ThroughAssociation
+end
+
 if defined?(Rails::DBConsole)
   Rails::DBConsole.instance_eval do
     if Rails.version < '6.1'

lib/chrono_model/patches/preloader.rb

@@ -75,6 +75,22 @@ def build_scope
           return scope
         end
       end
+
+      module ThroughAssociation
+        # Builds the preloader scope taking into account a potential
+        # +as_of_time+ passed down the call chain starting at the
+        # end user invocation.
+        #
+        def through_scope
+          scope = super
+
+          if preload_scope.try(:as_of_time)
+            scope = scope.as_of(preload_scope.as_of_time)
+          end
+
+          scope
+        end
+      end
     end
 
   end

spec/chrono_model/time_machine/as_of_spec.rb

@@ -143,6 +143,8 @@
       it { expect(Foo.as_of($t.foo.ts[0]).includes(:bars, :sub_bars).first.sub_bars.first).to be nil }
       it { expect(Foo.as_of($t.foo.ts[1]).includes(:bars, :sub_bars).first.sub_bars.first).to be nil }
 
+      it { expect(Foo.as_of($t.bar.ts[0]).includes(:sub_bars).first.bars.first.sub_bars.first).to be nil }
+
       it { expect(Foo.as_of($t.subbar.ts[0]).includes(:bars, :sub_bars).first.sub_bars.first.name).to eq 'sub-bar' }
       it { expect(Foo.as_of($t.subbar.ts[1]).includes(:bars, :sub_bars).first.sub_bars.first.name).to eq 'bar sub-bar' }
       it { expect(Foo.as_of($t.subbar.ts[2]).includes(:bars, :sub_bars).first.sub_bars.first.name).to eq 'sub-bar sub-bar' }