Use IdentityMap middleware to flush map on each request.

2 files changed, 15 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/identity_map.rb b/activerecord/lib/active_record/identity_map.rb
index 9f95685816..0062682555 100644
--- a/activerecord/lib/active_record/identity_map.rb
+++ b/activerecord/lib/active_record/identity_map.rb
@@ -95,5 +95,17 @@ module ActiveRecord
         ActiveRecord::IdentityMap
       end
     end
+
+    class Middleware
+      def initialize(app)
+        @app = app
+      end
+
+      def call(env)
+        @app.call(env)
+      ensure
+        ActiveRecord::IdentityMap.clear
+      end
+    end
   end
 end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index dfe255ad7c..5d0424a543 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -22,6 +22,9 @@ module ActiveRecord
     config.app_middleware.insert_after "::ActionDispatch::Callbacks",
       "ActiveRecord::ConnectionAdapters::ConnectionManagement"
 
+    config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+      "ActiveRecord::IdentityMap::Middleware"
+
     rake_tasks do
       load "active_record/railties/databases.rake"
     end