From 2813f94124c2ba14f1e4a51001e3898b0e0c32aa Mon Sep 17 00:00:00 2001
From: Damian Mooyman <damian@silverstripe.com>
Date: Fri, 30 Oct 2015 16:26:14 +1300
Subject: [PATCH] BUG Ensure that filters on any fixed field are scoped to the
 base data table Fixes #4700

---
 core/ClassInfo.php           | 18 +++++++++++-------
 tests/core/ClassInfoTest.php | 10 ++++++++++
 tests/model/DataListTest.php |  5 +++++
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/core/ClassInfo.php b/core/ClassInfo.php
index af166f77a..5d7672d3f 100644
--- a/core/ClassInfo.php
+++ b/core/ClassInfo.php
@@ -307,16 +307,20 @@ class ClassInfo {
 
 		//normalise class name
 		$candidateClass = self::class_name($candidateClass);
-
 		$exists = self::exists($candidateClass);
 
-		while($candidateClass && $candidateClass != 'DataObject' && $exists) {
-			if(DataObject::has_own_table($candidateClass)) {
-				$inst = singleton($candidateClass);
+		// Short circuit for fixed fields
+		$fixed = DataObject::config()->fixed_fields;
+		if($exists && isset($fixed[$fieldName])) {
+			return self::baseDataClass($candidateClass);
+		}
 
-				if($inst->hasOwnTableDatabaseField($fieldName)) {
-					break;
-				}
+		// Find regular field
+		while($candidateClass && $candidateClass != 'DataObject' && $exists) {
+			if( DataObject::has_own_table($candidateClass)
+				&& DataObject::has_own_table_database_field($candidateClass, $fieldName)
+			) {
+				break;
 			}
 
 			$candidateClass = get_parent_class($candidateClass);
diff --git a/tests/core/ClassInfoTest.php b/tests/core/ClassInfoTest.php
index 923564fcc..fd437f41e 100644
--- a/tests/core/ClassInfoTest.php
+++ b/tests/core/ClassInfoTest.php
@@ -197,6 +197,16 @@ class ClassInfoTest extends SapphireTest {
 		$this->assertNull(
 			ClassInfo::table_for_object_field(null, null)
 		);
+
+		// Test fixed fields
+		$this->assertEquals(
+			'ClassInfoTest_BaseDataClass',
+			ClassInfo::table_for_object_field('ClassInfoTest_HasFields', 'ID')
+		);
+		$this->assertEquals(
+			'ClassInfoTest_BaseDataClass',
+			ClassInfo::table_for_object_field('ClassInfoTest_NoFields', 'Created')
+		);
 	}
 }
 
diff --git a/tests/model/DataListTest.php b/tests/model/DataListTest.php
index b894daebc..7d7b453bc 100755
--- a/tests/model/DataListTest.php
+++ b/tests/model/DataListTest.php
@@ -400,6 +400,11 @@ class DataListTest extends SapphireTest {
 		// byID() returns a DataObject, rather than a DataList
 		$this->assertInstanceOf('DataObjectTest_Team', $team);
 		$this->assertEquals('Team 2', $team->Title);
+
+		// Assert that filtering on ID searches by the base table, not the child table field
+		$query = DataObjectTest_SubTeam::get()->filter('ID', 4)->sql($parameters);
+		$this->assertContains('WHERE ("DataObjectTest_Team"."ID" = ?)', $query);
+		$this->assertNotContains('WHERE ("DataObjectTest_SubTeam"."ID" = ?)', $query);
 	}
 
 	/**