From 157db89dbfdab0b542ba2c31f098d791657d02ef Mon Sep 17 00:00:00 2001
From: Mike Cochrane <mikec@mikenz.geek.nz>
Date: Thu, 14 Dec 2017 14:17:30 +1300
Subject: [PATCH] Bugfix: Don't assume all forms have a URLSegment field

---
 src/Extension/SiteTreeSubsites.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Extension/SiteTreeSubsites.php b/src/Extension/SiteTreeSubsites.php
index da23847..e12c01e 100644
--- a/src/Extension/SiteTreeSubsites.php
+++ b/src/Extension/SiteTreeSubsites.php
@@ -154,7 +154,9 @@ class SiteTreeSubsites extends DataExtension
             }
 
             $urlsegment = $fields->dataFieldByName('URLSegment');
-            $urlsegment->setURLPrefix($baseLink);
+            if ($urlsegment) {
+                $urlsegment->setURLPrefix($baseLink);
+            }
         }
     }