1 files changed, 9 insertions, 0 deletions
diff --git a/railties/lib/rails/commands/server.rb b/railties/lib/rails/commands/server.rb
index 9ef64da3ef..a684129353 100644
--- a/railties/lib/rails/commands/server.rb
+++ b/railties/lib/rails/commands/server.rb
@@ -87,6 +87,15 @@ module Rails
       middlewares = []
       middlewares << [Rails::Rack::Debugger]  if options[:debugger]
       middlewares << [::Rack::ContentLength]
+
+      # FIXME: add Rack::Lock in the case people are using webrick.
+      # This is to remain backwards compatible for those who are
+      # running webrick in production. We should consider removing this
+      # in development.
+      if server.name == 'Rack::Handler::WEBrick'
+        middlewares << [::Rack::Lock]
+      end
+
       Hash.new(middlewares)
     end