From f2de39162dc1f197de2fcf8e2c8e2947acdb3754 Mon Sep 17 00:00:00 2001
From: Andrew Aitken-Fincham <andrew.aitken-fincham@lendingworks.co.uk>
Date: Mon, 15 Oct 2018 14:27:09 +0100
Subject: [PATCH] API Allow dataobject get_one without passing a class

add class validation early in get_one()
---
 src/ORM/DataObject.php           | 20 +++++++++++++++-----
 tests/php/ORM/DataObjectTest.php |  6 ++++++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/ORM/DataObject.php b/src/ORM/DataObject.php
index b236b253c..8e3480e90 100644
--- a/src/ORM/DataObject.php
+++ b/src/ORM/DataObject.php
@@ -3399,24 +3399,34 @@ class DataObject extends ViewableData implements DataObjectInterface, i18nEntity
      * $member = DataObject::get_one('Member', [ '"FirstName"' => 'John' ]);
      * </code>
      *
-     * @param string $callerClass The class of objects to be returned
+     * @param string|null $callerClass The class of objects to be returned. Defaults to the class that calls the method
+     * e.g. MyObject::get_one() will return a MyObject
      * @param string|array $filter A filter to be inserted into the WHERE clause.
      * @param boolean $cache Use caching
-     * @param string $orderby A sort expression to be inserted into the ORDER BY clause.
+     * @param string $orderBy A sort expression to be inserted into the ORDER BY clause.
      *
      * @return DataObject|null The first item matching the query
      */
-    public static function get_one($callerClass, $filter = "", $cache = true, $orderby = "")
+    public static function get_one($callerClass = null, $filter = "", $cache = true, $orderBy = "")
     {
+        if ($callerClass === null) {
+            $callerClass = static::class;
+        }
+
+        // Validate class
+        if ($callerClass === self::class) {
+            throw new InvalidArgumentException('DataObject::get_one() cannot query non-subclass DataObject directly');
+        }
+
         /** @var DataObject $singleton */
         $singleton = singleton($callerClass);
 
-        $cacheComponents = [$filter, $orderby, $singleton->getUniqueKeyComponents()];
+        $cacheComponents = [$filter, $orderBy, $singleton->getUniqueKeyComponents()];
         $cacheKey = md5(serialize($cacheComponents));
 
         $item = null;
         if (!$cache || !isset(self::$_cache_get_one[$callerClass][$cacheKey])) {
-            $dl = DataObject::get($callerClass)->where($filter)->sort($orderby);
+            $dl = DataObject::get($callerClass)->where($filter)->sort($orderBy);
             $item = $dl->first();
 
             if ($cache) {
diff --git a/tests/php/ORM/DataObjectTest.php b/tests/php/ORM/DataObjectTest.php
index 9ec9e1629..04787f883 100644
--- a/tests/php/ORM/DataObjectTest.php
+++ b/tests/php/ORM/DataObjectTest.php
@@ -436,6 +436,12 @@ class DataObjectTest extends SapphireTest
         $this->assertEquals('Bob', $comment->Name);
         $comment = DataObject::get_one(DataObjectTest\TeamComment::class, '', true, '"Name" DESC');
         $this->assertEquals('Phil', $comment->Name);
+
+        // Test get_one() without passing classname
+        $this->assertEquals(
+            DataObjectTest\TeamComment::get_one(),
+            DataObject::get_one(DataObjectTest\TeamComment::class)
+        );
     }
 
     public function testGetByIDCallerClass()