[2.0] Fix querying fields in reference structures

lib/Doctrine/ODM/MongoDB/Persisters/DocumentPersister.php

@@ -1237,7 +1237,15 @@ private function prepareQueryElement($fieldName, $value = null, $class = null, $
                 ? $this->dm->getClassMetadata($targetMapping['targetDocument'])
                 : null;
 
-            $fieldNames = $this->prepareQueryElement($nextObjectProperty, $value, $nextTargetClass, $prepareValue);
+            if (empty($targetMapping['reference'])) {
+                $fieldNames = $this->prepareQueryElement($nextObjectProperty, $value, $nextTargetClass, $prepareValue);
+            } else {
+                // No recursive processing for references as most probably somebody is querying DBRef or alike
+                if ($nextObjectProperty[0] !== '$' && in_array($targetMapping['storeAs'], [ClassMetadata::REFERENCE_STORE_AS_DB_REF_WITH_DB, ClassMetadata::REFERENCE_STORE_AS_DB_REF])) {
+                    $nextObjectProperty = '$' . $nextObjectProperty;
+                }
+                $fieldNames = [[$nextObjectProperty, $value]];
+            }
 
             return array_map(function ($preparedTuple) use ($fieldName) {
                 list($key, $value) = $preparedTuple;

tests/Doctrine/ODM/MongoDB/Tests/Functional/QueryTest.php

@@ -8,12 +8,15 @@
 use Documents\Article;
 use Documents\CmsComment;
 use Documents\Group;
+use Documents\IndirectlyReferencedUser;
 use Documents\Phonenumber;
+use Documents\ReferenceUser;
 use Documents\User;
 use MongoDB\BSON\ObjectId;
 use MongoDB\BSON\UTCDateTime;
 use function array_values;
 use function get_class;
+use function iterator_to_array;
 use function strtotime;
 
 class QueryTest extends BaseTest
@@ -366,6 +369,35 @@ public function testQueryReferences()
         $this->assertSame($user, $user2);
     }
 
+    public function testNestedQueryReference()
+    {
+        $referencedUser = new User();
+        $referencedUser->setUsername('boo');
+        $phonenumber = new Phonenumber('6155139185');
+        $referencedUser->addPhonenumber($phonenumber);
+
+        $indirectlyReferencedUser = new IndirectlyReferencedUser();
+        $indirectlyReferencedUser->user = $referencedUser;
+
+        $user = new ReferenceUser();
+        $user->indirectlyReferencedUsers[] = $indirectlyReferencedUser;
+
+        $this->dm->persist($referencedUser);
+        $this->dm->persist($user);
+        $this->dm->flush();
+
+        $qb = $this->dm->createQueryBuilder('Documents\ReferenceUser');
+
+        $referencedUsersQuery = $qb
+            ->field('indirectlyReferencedUsers.user.id')->equals(new ObjectId($referencedUser->getId()))
+            ->getQuery();
+
+        $referencedUsers = iterator_to_array($referencedUsersQuery->execute(), false);
+
+        $this->assertCount(1, $referencedUsers);
+        $this->assertSame($user, $referencedUsers[0]);
+    }
+
     public function testQueryWhereIn()
     {
         $qb = $this->dm->createQueryBuilder(User::class);

tests/Doctrine/ODM/MongoDB/Tests/QueryTest.php

@@ -299,8 +299,22 @@ public function testQueryWithMultipleEmbeddedDocumentsAndReference()
         $query = $qb->getQuery();
         $debug = $query->debug('query');
 
-        $this->assertArrayHasKey('eO.eO.e1.eO.eP.pO._id', $debug);
-        $this->assertEquals($identifier, $debug['eO.eO.e1.eO.eP.pO._id']);
+        $this->assertArrayHasKey('eO.eO.e1.eO.eP.pO.$id', $debug);
+        $this->assertEquals($identifier, $debug['eO.eO.e1.eO.eP.pO.$id']);
+    }
+
+    public function testQueryWithMultipleEmbeddedDocumentsAndReferenceUsingDollarSign()
+    {
+        $identifier = new ObjectId();
+
+        $qb = $this->dm->createQueryBuilder(__NAMESPACE__ . '\EmbedTest')
+            ->find()
+            ->field('embeddedOne.embeddedOne.embeddedMany.embeddedOne.pet.owner.$id')->equals((string) $identifier);
+        $query = $qb->getQuery();
+        $debug = $query->debug('query');
+
+        $this->assertArrayHasKey('eO.eO.e1.eO.eP.pO.$id', $debug);
+        $this->assertEquals($identifier, $debug['eO.eO.e1.eO.eP.pO.$id']);
     }
 
     public function testSelectVsSingleCollectionInheritance()

tests/Documents/IndirectlyReferencedUser.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Documents;
+
+use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
+
+/**
+ * @ODM\EmbeddedDocument
+ */
+class IndirectlyReferencedUser
+{
+    /**
+     * @var User
+     *
+     * @ODM\ReferenceOne(targetDocument="Documents\User", storeAs="ref")
+     */
+    public $user;
+}

tests/Documents/ReferenceUser.php

@@ -72,6 +72,13 @@ class ReferenceUser
      */
     public $referencedUsers = [];
 
+    /**
+     * @ODM\EmbedMany(targetDocument="Documents\IndirectlyReferencedUser")
+     *
+     * @var IndirectlyReferencedUser[]
+     */
+    public $indirectlyReferencedUsers = [];
+
     /**
      * @ODM\Field(type="string")
      *