From 311fd62d9527a47586d90a6f4e2c80922d15d44f Mon Sep 17 00:00:00 2001
From: Robbie Averill <robbie@silverstripe.com>
Date: Fri, 19 Oct 2018 18:11:15 +0200
Subject: [PATCH 1/2] FIX getExtensionInstance can return null, add a case to
 handle that

---
 src/Core/Extensible.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Core/Extensible.php b/src/Core/Extensible.php
index de40620b6..b29dda32e 100644
--- a/src/Core/Extensible.php
+++ b/src/Core/Extensible.php
@@ -135,6 +135,10 @@ trait Extensible
                 $this->addCallbackMethod($method, function ($inst, $args) use ($method, $extensionClass) {
                     /** @var Extensible $inst */
                     $extension = $inst->getExtensionInstance($extensionClass);
+                    if (!$extension) {
+                        return null;
+                    }
+
                     try {
                         $extension->setOwner($inst);
                         return call_user_func_array([$extension, $method], $args);

From 7f6f5c9ec9352172f37f8980d823e85c1c39062a Mon Sep 17 00:00:00 2001
From: Robbie Averill <robbie@silverstripe.com>
Date: Sat, 20 Oct 2018 13:59:03 +0200
Subject: [PATCH 2/2] FIX Flush extra methods cache on DataObjects after each
 unit test class has finished

---
 src/Dev/State/ExtensionTestState.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Dev/State/ExtensionTestState.php b/src/Dev/State/ExtensionTestState.php
index ea0859915..2cfedddbd 100644
--- a/src/Dev/State/ExtensionTestState.php
+++ b/src/Dev/State/ExtensionTestState.php
@@ -85,5 +85,6 @@ class ExtensionTestState implements TestState
 
     public function tearDownOnce($class)
     {
+        DataObject::flush_extra_methods_cache();
     }
 }