Return false in production environments

CHANGELOG.md

@@ -1,5 +1,9 @@
 **Please note that Webpacker 3.1.0 and 3.1.1 has some serious bugs so please consider using either 3.0.2 or 3.2.0**
 
+## [Unreleased]
+
+- Disable dev server running? check if no dev server config is present in that environment [#1179](https://github.com/rails/webpacker/pull/1179)
+
 ## [3.2.0] - 2017-12-16
 
 ### To upgrade:

lib/webpacker/dev_server.rb

@@ -10,8 +10,12 @@ def initialize(webpacker)
   end
 
   def running?
-    Socket.tcp(host, port, connect_timeout: connect_timeout).close
-    true
+    if config.dev_server.present?
+      Socket.tcp(host, port, connect_timeout: connect_timeout).close
+      true
+    else
+      false
+    end
   rescue
     false
   end

test/dev_server_test.rb

@@ -1,6 +1,13 @@
 require "test_helper"
 
 class DevServerTest < Webpacker::Test
+  def test_running?
+    with_node_env("production") do
+      reloaded_config
+      refute Webpacker.dev_server.running?
+    end
+  end
+
   def test_host
     with_node_env("development") do
       reloaded_config