From e72fc9e3d0f35a1d43f55f83f9919f67d72fb7cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sam=20Minn=C3=A9e?= <sam@silverstripe.com>
Date: Thu, 25 Oct 2018 11:42:45 +1300
Subject: [PATCH 1/2] FIX DataObject singleton creation (#8516)

Ensure DataObject instances are aware they are singletons so functions like populateDefaults() can be skipped. (fixes #4878)

Correctly applies https://github.com/silverstripe/silverstripe-framework/pull/7850 to the 4.x line
This has already been fixed in 3.x
---
 src/Core/Injector/Injector.php   |  9 +++++++
 tests/php/ORM/DataObjectTest.php | 45 ++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/src/Core/Injector/Injector.php b/src/Core/Injector/Injector.php
index 6b0885132..6cf980cbf 100644
--- a/src/Core/Injector/Injector.php
+++ b/src/Core/Injector/Injector.php
@@ -13,6 +13,7 @@ use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Environment;
 use SilverStripe\Dev\Deprecation;
+use SilverStripe\ORM\DataObject;
 
 /**
  * A simple injection manager that manages creating objects and injecting
@@ -581,6 +582,14 @@ class Injector implements ContainerInterface
             $constructorParams = $spec['constructor'];
         }
 
+        // If we're dealing with a DataObject singleton without specific constructor params, pass through Singleton
+        // flag as second argument
+        if ((!$type || $type !== self::PROTOTYPE)
+            && empty($constructorParams)
+            && is_subclass_of($class, DataObject::class)) {
+            $constructorParams = array(null, true);
+        }
+
         $factory = isset($spec['factory']) ? $this->get($spec['factory']) : $this->getObjectCreator();
         $object = $factory->create($class, $constructorParams);
 
diff --git a/tests/php/ORM/DataObjectTest.php b/tests/php/ORM/DataObjectTest.php
index 55c2ea659..3a2158c4c 100644
--- a/tests/php/ORM/DataObjectTest.php
+++ b/tests/php/ORM/DataObjectTest.php
@@ -66,6 +66,51 @@ class DataObjectTest extends SapphireTest
         );
     }
 
+    /**
+     * @dataProvider provideSingletons
+     */
+    public function testSingleton($inst, $defaultValue, $altDefaultValue)
+    {
+        $inst = $inst();
+        // Test that populateDefaults() isn't called on singletons
+        // which can lead to SQL errors during build, and endless loops
+        if ($defaultValue) {
+            $this->assertEquals($defaultValue, $inst->MyFieldWithDefault);
+        } else {
+            $this->assertEmpty($inst->MyFieldWithDefault);
+        }
+
+        if ($altDefaultValue) {
+            $this->assertEquals($altDefaultValue, $inst->MyFieldWithAltDefault);
+        } else {
+            $this->assertEmpty($inst->MyFieldWithAltDefault);
+        }
+    }
+
+    public function provideSingletons()
+    {
+        // because PHPUnit evalutes test providers *before* setUp methods
+        // any extensions added in the setUp methods won't be available
+        // we must return closures to generate the arguments at run time
+        return array(
+            'create() static method' => array(function () {
+                return DataObjectTest\Fixture::create();
+            }, 'Default Value', 'Default Value'),
+            'New object creation' => array(function () {
+                return new DataObjectTest\Fixture();
+            }, 'Default Value', 'Default Value'),
+            'singleton() function' => array(function () {
+                return singleton(DataObjectTest\Fixture::class);
+            }, null, null),
+            'singleton() static method' => array(function () {
+                return DataObjectTest\Fixture::singleton();
+            }, null, null),
+            'Manual constructor args' => array(function () {
+                return new DataObjectTest\Fixture(null, true);
+            }, null, null),
+        );
+    }
+
     public function testDb()
     {
         $schema = DataObject::getSchema();

From 46e4c19070688df74757bd9a44dc2f0b2fdcd6a9 Mon Sep 17 00:00:00 2001
From: Maxime Rainville <maxime@silverstripe.com>
Date: Thu, 1 Nov 2018 22:38:26 +1300
Subject: [PATCH 2/2] MINOR Add a reference to SS_Object in .upgrade.yml to
 allow upgrade from SS3.7

---
 .upgrade.yml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.upgrade.yml b/.upgrade.yml
index e4e2c392a..33d42e81e 100644
--- a/.upgrade.yml
+++ b/.upgrade.yml
@@ -958,6 +958,9 @@ warnings:
     'Object':
       message: 'Replaced with traits'
       url: 'https://docs.silverstripe.org/en/4/changelogs/4.0.0#object-replace'
+    'SS_Object':
+      message: 'Replaced with traits'
+      url: 'https://docs.silverstripe.org/en/4/changelogs/4.0.0#object-replace'
     'SS_Log':
       message: 'Replaced with a PSR-3 logger'
       url: 'https://docs.silverstripe.org/en/4/changelogs/4.0.0#psr3-logging'