Remove partial syntax in DQL

It is no longer possible to use the "PARTIAL" keyword in a DQL query, or
to artificially build an AST with a partial object expression. It is
still possible to use the result set mapping API to build partial
objects.

UPGRADE.md

@@ -1,5 +1,12 @@
 # Upgrade to 3.0
 
+## BC BREAK: Partial objects are removed
+
+- The `PARTIAL` keyword no longer exists.
+- `Doctrine\ORM\Query\AST\PartialObjectExpression`is removed.
+- `Doctrine\ORM\Query\SqlWalker::HINT_PARTIAL` and
+  `Doctrine\ORM\Query::HINT_FORCE_PARTIAL_LOAD` are removed.
+
 ## BC BREAK: `Doctrine\ORM\Persister\Entity\EntityPersister::executeInserts()` return type changed to `void`
 
 Implementors should adapt to the new signature, and should call

docs/en/reference/dql-doctrine-query-language.rst

@@ -518,33 +518,6 @@ when the DQL is switched to an arbitrary join.
     - HAVING is applied to the results of a query after
       aggregation (GROUP BY)
 
-
-Partial Object Syntax
-^^^^^^^^^^^^^^^^^^^^^
-
-By default when you run a DQL query in Doctrine and select only a
-subset of the fields for a given entity, you do not receive objects
-back. Instead, you receive only arrays as a flat rectangular result
-set, similar to how you would if you were just using SQL directly
-and joining some data.
-
-If you want to select partial objects you can use the ``partial``
-DQL keyword:
-
-.. code-block:: php
-
-    <?php
-    $query = $em->createQuery('SELECT partial u.{id, username} FROM CmsUser u');
-    $users = $query->getResult(); // array of partially loaded CmsUser objects
-
-You use the partial syntax when joining as well:
-
-.. code-block:: php
-
-    <?php
-    $query = $em->createQuery('SELECT partial u.{id, username}, partial a.{id, name} FROM CmsUser u JOIN u.articles a');
-    $users = $query->getResult(); // array of partially loaded CmsUser objects
-
 "NEW" Operator Syntax
 ^^^^^^^^^^^^^^^^^^^^^
 
@@ -1417,15 +1390,6 @@ exist mostly internal query hints that are not be consumed in
 userland. However the following few hints are to be used in
 userland:
 
-
--  ``Query::HINT_FORCE_PARTIAL_LOAD`` - Allows to hydrate objects
-   although not all their columns are fetched. This query hint can be
-   used to handle memory consumption problems with large result-sets
-   that contain char or binary data. Doctrine has no way of implicitly
-   reloading this data. Partially loaded objects have to be passed to
-   ``EntityManager::refresh()`` if they are to be reloaded fully from
-   the database. This query hint is deprecated and will be removed
-   in the future (\ `Details <https://github.com/doctrine/orm/issues/8471>`_)
 -  ``Query::HINT_REFRESH`` - This query is used internally by
    ``EntityManager::refresh()`` and can be used in userland as well.
    If you specify this hint and a query returns the data for an entity
@@ -1678,10 +1642,8 @@ Select Expressions
 
 .. code-block:: php
 
-    SelectExpression        ::= (IdentificationVariable | ScalarExpression | AggregateExpression | FunctionDeclaration | PartialObjectExpression | "(" Subselect ")" | CaseExpression | NewObjectExpression) [["AS"] ["HIDDEN"] AliasResultVariable]
+    SelectExpression        ::= (IdentificationVariable | ScalarExpression | AggregateExpression | FunctionDeclaration | "(" Subselect ")" | CaseExpression | NewObjectExpression) [["AS"] ["HIDDEN"] AliasResultVariable]
     SimpleSelectExpression  ::= (StateFieldPathExpression | IdentificationVariable | FunctionDeclaration | AggregateExpression | "(" Subselect ")" | ScalarExpression) [["AS"] AliasResultVariable]
-    PartialObjectExpression ::= "PARTIAL" IdentificationVariable "." PartialFieldSet
-    PartialFieldSet         ::= "{" SimpleStateField {"," SimpleStateField}* "}"
     NewObjectExpression     ::= "NEW" AbstractSchemaName "(" NewObjectArg {"," NewObjectArg}* ")"
     NewObjectArg            ::= ScalarExpression | "(" Subselect ")"
 

lib/Doctrine/ORM/Cache/DefaultQueryCache.php

@@ -16,7 +16,6 @@
 use Doctrine\ORM\PersistentCollection;
 use Doctrine\ORM\Query;
 use Doctrine\ORM\Query\ResultSetMapping;
-use Doctrine\ORM\Query\SqlWalker;
 use Doctrine\ORM\UnitOfWork;
 
 use function array_map;
@@ -211,10 +210,6 @@ public function put(QueryCacheKey $key, ResultSetMapping $rsm, mixed $result, ar
             throw FeatureNotImplemented::nonSelectStatements();
         }
 
-        if (($hints[SqlWalker::HINT_PARTIAL] ?? false) === true || ($hints[Query::HINT_FORCE_PARTIAL_LOAD] ?? false) === true) {
-            throw FeatureNotImplemented::partialEntities();
-        }
-
         if (! ($key->cacheMode & Cache::MODE_PUT)) {
             return false;
         }

lib/Doctrine/ORM/Cache/Exception/FeatureNotImplemented.php

@@ -20,9 +20,4 @@ public static function nonSelectStatements(): self
     {
         return new self('Second-level cache query supports only select statements.');
     }
-
-    public static function partialEntities(): self
-    {
-        return new self('Second level cache does not support partial entities.');
-    }
 }

lib/Doctrine/ORM/Query.php

@@ -68,14 +68,6 @@ final class Query extends AbstractQuery
      */
     public const HINT_REFRESH_ENTITY = 'doctrine.refresh.entity';
 
-    /**
-     * The forcePartialLoad query hint forces a particular query to return
-     * partial objects.
-     *
-     * @todo Rename: HINT_OPTIMIZE
-     */
-    public const HINT_FORCE_PARTIAL_LOAD = 'doctrine.forcePartialLoad';
-
     /**
      * The includeMetaColumns query hint causes meta columns like foreign keys and
      * discriminator columns to be selected and returned as part of the query result.