[GH-8471] undeprecate partials completly

UPGRADE.md

@@ -8,10 +8,12 @@ change in behavior.
 
 Progress on this is tracked at https://github.com/doctrine/orm/issues/11624 .
 
-## PARTIAL DQL syntax is undeprecated for non-object hydration
+## PARTIAL DQL syntax is undeprecated 
 
-Use of the PARTIAL keyword is not deprecated anymore in DQL when used with a hydrator
-that is not creating entities, such as the ArrayHydrator.
+Use of the PARTIAL keyword is not deprecated anymore in DQL, because we will be
+able to support PARTIAL objects with PHP 8.4 Lazy Objects and
+Symfony/VarExporter in a better way. When we decided to remove this feature
+these two abstractions did not exist yet.
 
 ## Deprecate `\Doctrine\ORM\Query\Parser::setCustomOutputTreeWalker()`
 

src/Query/Parser.php

@@ -1852,14 +1852,6 @@ public function JoinAssociationDeclaration()
      */
     public function PartialObjectExpression()
     {
-        if ($this->query->getHydrationMode() === Query::HYDRATE_OBJECT) {
-            Deprecation::trigger(
-                'doctrine/orm',
-                'https://github.com/doctrine/orm/issues/8471',
-                'PARTIAL syntax in DQL is deprecated for object hydration.'
-            );
-        }
-
         $this->match(TokenType::T_PARTIAL);
 
         $partialFieldSet = [];

src/UnitOfWork.php

@@ -2920,15 +2920,6 @@ private function newInstance(ClassMetadata $class)
      */
     public function createEntity($className, array $data, &$hints = [])
     {
-        if (isset($hints[SqlWalker::HINT_PARTIAL])) {
-            Deprecation::trigger(
-                'doctrine/orm',
-                'https://github.com/doctrine/orm/issues/8471',
-                'Partial Objects are deprecated for object hydration (here entity %s)',
-                $className
-            );
-        }
-
         $class = $this->em->getClassMetadata($className);
 
         $id     = $this->identifierFlattener->flattenIdentifier($class, $data);