From 4744aa6920c73a9a244e5b5b12dbc630b0a35282 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Bajto=C5=A1?= <miroslav@strongloop.com>
Date: Mon, 15 Dec 2014 08:14:26 +0100
Subject: [PATCH] server-app: make _sortLayersByPhase stable

Fix the phase-sorting algorithm to use a stable sorting algorithm,
since the built-in `Array.prototype.sort` is not stable.
---
 lib/server-app.js |  3 ++-
 package.json      |  1 +
 test/app.test.js  | 20 ++++++++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/server-app.js b/lib/server-app.js
index 7788dd9e..13f993a8 100644
--- a/lib/server-app.js
+++ b/lib/server-app.js
@@ -3,6 +3,7 @@ var express = require('express');
 var merge = require('util')._extend;
 var mergePhaseNameLists = require('loopback-phase').mergePhaseNameLists;
 var debug = require('debug')('loopback:app');
+var stableSortInPlace = require('stable').inplace;
 
 var BUILTIN_MIDDLEWARE = { builtin: true };
 
@@ -214,7 +215,7 @@ proto._sortLayersByPhase = function() {
   });
 
   var router = this._router;
-  router.stack.sort(compareLayers);
+  stableSortInPlace(router.stack, compareLayers);
 
   function compareLayers(left, right) {
     var leftPhase = left.phase;
diff --git a/package.json b/package.json
index bae83f44..ad3ef774 100644
--- a/package.json
+++ b/package.json
@@ -46,6 +46,7 @@
     "nodemailer": "~1.3.0",
     "nodemailer-stub-transport": "~0.1.4",
     "serve-favicon": "^2.1.6",
+    "stable": "^0.1.5",
     "strong-remoting": "^2.4.0",
     "uid2": "0.0.3",
     "underscore.string": "~2.3.3"
diff --git a/test/app.test.js b/test/app.test.js
index 978773ac..18f326c4 100644
--- a/test/app.test.js
+++ b/test/app.test.js
@@ -239,6 +239,26 @@ describe('app', function() {
       });
     });
 
+    it('preserves order of middleware in the same phase', function(done) {
+      // while we are discouraging developers from depending on
+      // the registration order of middleware in the same phase,
+      // we must preserve the order for compatibility with `app.use`
+      // and `app.route`.
+
+      // we need at least 9 elements to expose non-stability
+      // of the built-in sort function
+      var numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+      numbers.forEach(function(n) {
+        app.middleware('routes', namedHandler(n));
+      });
+
+      executeMiddlewareHandlers(app, function(err) {
+        if (err) return done;
+        expect(steps).to.eql(numbers);
+        done();
+      });
+    });
+
     it('correctly mounts express apps', function(done) {
       var data;
       var mountWasEmitted;