NEW Add extension point to DataObject->hydrate()

src/ORM/DataObject.php

@@ -462,13 +462,29 @@ private function hydrate(array $record, bool $mustHaveID)
             static::class,
             DataObjectSchema::INCLUDE_CLASS | DataObjectSchema::DB_ONLY
         );
+
         foreach ($fields as $field => $fieldSpec) {
             $fieldClass = strtok($fieldSpec, ".");
             if (!array_key_exists($field, $record)) {
                 $this->record[$field . '_Lazy'] = $fieldClass;
             }
         }
 
+        // Extension point to hydrate additional fields into this object during construction.
+        // Return an array of field names => raw values from your augmentHydrateFields extension method.
+        $extendedAdditionalFields = $this->extend('augmentHydrateFields');
+        foreach ($extendedAdditionalFields as $additionalFields) {
+            foreach ($additionalFields as $field => $value) {
+                $this->record[$field] = $value;
+
+                // If a corresponding lazy-load field exists, remove it as the value has been provided
+                $lazyName = $field . '_Lazy';
+                if (array_key_exists($lazyName, $this->record)) {
+                    unset($this->record[$lazyName]);
+                }
+            }
+        }
+
         $this->original = $this->record;
         $this->changed = [];
         $this->changeForced = false;

tests/php/ORM/DataObjectTest.php

@@ -19,6 +19,7 @@
 use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\Tests\DataObjectTest\Company;
 use SilverStripe\ORM\Tests\DataObjectTest\Player;
+use SilverStripe\ORM\Tests\DataObjectTest\Team;
 use SilverStripe\ORM\Tests\DataObjectTest\TreeNode;
 use SilverStripe\Security\Member;
 use SilverStripe\View\ViewableData;
@@ -211,6 +212,31 @@ public function testConstructAcceptsValues()
         $this->assertSame(5, $player->ID);
     }
 
+    /**
+     * @see SilverStripe\ORM\Tests\DataObjectTest\Team_Extension
+     */
+    public function testConstructHydratesAugmentedValues()
+    {
+        // When creating a DataObject from singleton, DataObject::hydrate() isn't called
+        $team = new Team([], DataObject::CREATE_SINGLETON);
+        $this->assertNull($team->CustomHydratedField);
+
+        // Similarly, when hydrating by creating a DataObject from nothing, hydrate() isn't called
+        $team2 = new Team([]);
+        $id = $team2->write();
+        $this->assertNull($team2->CustomHydratedField);
+
+        // However when rebuilding an object from the database, it is and we can expect our extension to execute
+        /** @var Team $team3 */
+        $team3 = Team::get()->byID($id);
+        $this->assertTrue($team3->CustomHydratedField);
+
+        // Also when rebuilding an object in memory, hydrate() is called and our extension should execute
+        /** @var Team $team4 */
+        $team4 = $team->newClassInstance(Team::class);
+        $this->assertTrue($team4->CustomHydratedField);
+    }
+
     public function testValidObjectsForBaseFields()
     {
         $obj = new DataObjectTest\ValidatedObject();

tests/php/ORM/DataObjectTest/Team.php

@@ -12,6 +12,7 @@
  * @property string DatabaseField
  * @property array SalaryCap
  * @property string FoundationYear
+ * @property bool CustomHydratedField
  * @method Player Captain()
  * @method Player Founder()
  * @method Player HasOneRelationship()

tests/php/ORM/DataObjectTest/Team_Extension.php

@@ -23,4 +23,11 @@ public function getExtendedDynamicField()
     {
         return "extended dynamic field";
     }
+
+    public function augmentHydrateFields()
+    {
+        return [
+            'CustomHydratedField' => true,
+        ];
+    }
 }