From 071aad4815bae1d584f50a982f68ec9ace2cecfd Mon Sep 17 00:00:00 2001
From: Frederic Junod <frederic.junod@camptocamp.com>
Date: Wed, 18 Nov 2015 11:30:10 +0100
Subject: [PATCH] Check ol.source.UrlTile#urls property for null value

Fixes #4446
---
 src/ol/source/tilearcgisrestsource.js     |  2 +-
 src/ol/source/tilewmssource.js            | 10 ++++++----
 test/spec/ol/source/tilewmssource.test.js | 10 ++++++++++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/ol/source/tilearcgisrestsource.js b/src/ol/source/tilearcgisrestsource.js
index bd37a418d6..47ec86fd0f 100644
--- a/src/ol/source/tilearcgisrestsource.js
+++ b/src/ol/source/tilearcgisrestsource.js
@@ -91,7 +91,7 @@ ol.source.TileArcGISRest.prototype.getRequestUrl_ =
         pixelRatio, projection, params) {
 
   var urls = this.urls;
-  if (urls.length === 0) {
+  if (!urls) {
     return undefined;
   }
 
diff --git a/src/ol/source/tilewmssource.js b/src/ol/source/tilewmssource.js
index f17caee76a..47b66b23ac 100644
--- a/src/ol/source/tilewmssource.js
+++ b/src/ol/source/tilewmssource.js
@@ -212,7 +212,7 @@ ol.source.TileWMS.prototype.getRequestUrl_ =
         pixelRatio, projection, params) {
 
   var urls = this.urls;
-  if (urls.length === 0) {
+  if (!urls) {
     return undefined;
   }
 
@@ -298,9 +298,11 @@ ol.source.TileWMS.prototype.resetCoordKeyPrefix_ = function() {
   var i = 0;
   var res = [];
 
-  var j, jj;
-  for (j = 0, jj = this.urls.length; j < jj; ++j) {
-    res[i++] = this.urls[j];
+  if (this.urls) {
+    var j, jj;
+    for (j = 0, jj = this.urls.length; j < jj; ++j) {
+      res[i++] = this.urls[j];
+    }
   }
 
   var key;
diff --git a/test/spec/ol/source/tilewmssource.test.js b/test/spec/ol/source/tilewmssource.test.js
index 8fcc0ac64e..d5de725a24 100644
--- a/test/spec/ol/source/tilewmssource.test.js
+++ b/test/spec/ol/source/tilewmssource.test.js
@@ -13,6 +13,16 @@ describe('ol.source.TileWMS', function() {
     };
   });
 
+  describe('constructor', function() {
+    it('can be constructed without url or urls params', function() {
+      var source = new ol.source.TileWMS({
+        projection: 'EPSG:3857',
+        tileGrid: ol.tilegrid.createXYZ({maxZoom: 6})
+      });
+      expect(source).to.be.an(ol.source.TileWMS);
+    });
+  });
+
   describe('#getTile', function() {
 
     it('returns a tile with the expected URL', function() {