FIX Ensure all fixed fields are added

src/ORM/DataQuery.php

@@ -207,7 +207,11 @@ class DataQuery
             $queriedColumns = $this->queriedColumns;
         }
         if ($queriedColumns) {
-            $queriedColumns = array_merge($queriedColumns, ['Created', 'LastEdited', 'ClassName']);
+            // Add fixed fields to the query
+            // ID is a special case and gets added separately later
+            $fixedFields = DataObject::config()->uninherited('fixed_fields');
+            unset($fixedFields['ID']);
+            $queriedColumns = array_merge($queriedColumns, array_keys($fixedFields));
         }
         $query = clone $this->query;
 

tests/php/ORM/DataQueryFixedFieldsTest.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace SilverStripe\ORM\Tests;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\ORM\DataObject;
+use SilverStripe\ORM\DataQuery;
+
+class DataQueryFixedFieldsTest extends SapphireTest
+{
+    protected static $fixture_file = 'DataQueryFixedFieldsTest.yml';
+
+    protected static $extra_dataobjects = [
+        DataQueryTest\ObjectA::class,
+    ];
+
+    public static function setUpBeforeClass(): void
+    {
+        parent::setUpBeforeClass();
+        DataObject::config()->merge('fixed_fields', ['ExtraFixedField' => 'Varchar']);
+        static::tempDB()->resetDBSchema(static::$extra_dataobjects);
+    }
+
+    public function testDataQueryHasFixedFields()
+    {
+        $dataQuery = new DataQuery(DataQueryTest\ObjectA::class);
+        $dataQuery->setQueriedColumns(['Name']);
+        $this->assertSame(['This is the field'], $dataQuery->execute()->column('ExtraFixedField'));
+    }
+}

tests/php/ORM/DataQueryFixedFieldsTest.yml

@@ -0,0 +1,4 @@
+SilverStripe\ORM\Tests\DataQueryTest\ObjectA:
+  query1:
+    Name: 'Only one object'
+    ExtraFixedField: 'This is the field'