warn if node is not launched with 'NODE_ENV=production'

lib/env.js

@@ -72,6 +72,8 @@ module.exports.create = function (config) {
         NO_SANDBOX: NO_SANDBOX,
         httpSafePort: httpSafePort,
 
+        NODE_ENV: process.env.NODE_ENV,
+
         shouldUpdateNode: !isRecentVersion(),
 
         version: Package.version,

server.js

@@ -332,6 +332,9 @@ nThen(function (w) {
                 currentVersion: process.version,
             });
         }
+        if (Env.NODE_ENV !== 'production') {
+            Env.Log.warn("NODE_ENV", `If this server is running in a production context then it is recommended that you set NODE_ENV=production to prevent Expressjs from responding with stack traces when it catches an error.`);
+        }
 
         if (Env.OFFLINE_MODE) { return; }
         if (Env.websocketPath) { return; }