Merge pull request #28057 from eugeneius/clear_active_connections

Clear active connections after initialization

activerecord/lib/active_record/railtie.rb

@@ -166,5 +166,13 @@ class Railtie < Rails::Railtie # :nodoc:
       path = app.paths["db"].first
       config.watchable_files.concat ["#{path}/schema.rb", "#{path}/structure.sql"]
     end
+
+    initializer "active_record.clear_active_connections" do
+      config.after_initialize do
+        ActiveSupport.on_load(:active_record) do
+          clear_active_connections!
+        end
+      end
+    end
   end
 end

railties/test/application/initializers/frameworks_test.rb

@@ -262,5 +262,13 @@ def show
         Rails.env = orig_rails_env if orig_rails_env
       end
     end
+
+    test "connections checked out during initialization are returned to the pool" do
+      app_file "config/initializers/active_record.rb", <<-RUBY
+        ActiveRecord::Base.connection
+      RUBY
+      require "#{app_path}/config/environment"
+      assert !ActiveRecord::Base.connection_pool.active_connection?
+    end
   end
 end