Replace Array.filter with Array.splice, to prevent the creation of a new...

lib/instrumentation/express.js

@@ -403,7 +403,13 @@ module.exports = function initialize(agent, express) {
   function removeInterceptor(app) {
     if (app.stack && app.stack.length) {
       // Remove our custom error handler.
-      app.stack = app.stack.filter(function cb_filter(m) { return m !== interceptor })
+      // Move backwards so the index is not affected by the splicing.
+      var i = app.stack.length - 1;
+      for (; i >= 0; i--) {
+        if (app.stack[i] === interceptor) {
+          app.stack.splice(i, 1);
+        }
+      }
     }
   }
 

package.json

@@ -80,6 +80,7 @@
     "connect": "*",
     "cover": "*",
     "express": "*",
+    "express-enrouten": "^1.1.1",
     "generic-pool": "*",
     "glob": "~3.2.9",
     "hapi": "*",

test/versioned/express4-ejs/express4-express-enrouten.tap.js

@@ -0,0 +1,43 @@
+/**
+ * This test checks for regressions on the route stack manipulation for Express apps.
+ */
+'use strict'
+
+var path    = require('path')
+    , test    = require('tap').test
+    , request = require('request')
+    , helper  = require('../../lib/agent_helper.js')
+
+
+test("Express 4 + express-enrouten compatibility test", function (t) {
+    t.plan(2)
+
+    var agent   = helper.instrumentMockedAgent()
+        , express = require('express')
+        , enrouten= require('express-enrouten')
+        , app     = express()
+        , server  = require('http').createServer(app)
+
+    app.use(enrouten({directory:'./fixtures'}));
+
+    this.tearDown(function cb_tearDown() {
+        server.close(function cb_close() {
+            helper.unloadAgent(agent)
+        })
+    })
+
+
+    //New Relic + express-enrouten used to have a bug, where any routes after the first one would be lost.
+    server.listen(8080, function () {
+        request.get('http://localhost:8080/',
+            function (error, res, body) {
+
+                t.equal(res.statusCode, 200, 'First Route loaded')
+            })
+
+        request.get('http://localhost:8080/foo',
+            function (error, res, body) {
+                t.equal(res.statusCode, 200, 'Second Route loaded')
+            })
+    })
+});

test/versioned/express4-ejs/fixtures/index.js

@@ -0,0 +1,19 @@
+/**
+ * Created by lmarkus on 11/24/14.
+ */
+var routes = function(router){
+
+    router.get('/',function(req,res){
+        res.send('kraken');
+        res.end();
+
+    });
+
+    router.get('/foo',function(req,res){
+        res.send('kraken-foo');
+        res.end();
+    })
+
+};
+
+module.exports = routes;