Fix wrong syntax for replaceRoot stage

CHANGELOG-1.6.md

@@ -4,6 +4,11 @@ CHANGELOG for 1.6.x
 This changelog references the relevant changes (bug and security fixes) done
 in 1.6.x patch versions.
 
+1.6.4 (2019-07-10)
+------------------
+
+ * [#333](https://github.com/doctrine/mongodb/pull/333): Fix wrong syntax for replaceRoot stage
+
 1.6.3 (2018-07-20)
 ------------------
 

lib/Doctrine/MongoDB/Aggregation/Stage/ReplaceRoot.php

@@ -4,6 +4,7 @@
 
 use Doctrine\MongoDB\Aggregation\Builder;
 use Doctrine\MongoDB\Aggregation\Expr;
+use function is_array;
 
 /**
  * Fluent interface for adding a $replaceRoot stage to an aggregation pipeline.
@@ -35,8 +36,12 @@ public function __construct(Builder $builder, $expression = null)
      */
     public function getExpression()
     {
+        $expression = $this->expression !== null ? $this->convertExpression($this->expression) : $this->expr->getExpression();
+
         return [
-            '$replaceRoot' => $this->expression !== null ? $this->convertExpression($this->expression) : $this->expr->getExpression()
+            '$replaceRoot' => [
+                'newRoot' => is_array($expression) ? (object) $expression : $expression,
+            ],
         ];
     }
 

tests/Doctrine/MongoDB/Tests/Aggregation/Stage/ReplaceRootTest.php

@@ -17,7 +17,16 @@ public function testReplaceRootStage()
             ->field('product')
             ->multiply('$field', 5);
 
-        $this->assertSame(['$replaceRoot' => ['product' => ['$multiply' => ['$field', 5]]]], $replaceRootStage->getExpression());
+        $this->assertEquals(
+            [
+                '$replaceRoot' => [
+                    'newRoot' => (object) [
+                        'product' => ['$multiply' => ['$field', 5]],
+                    ],
+                ],
+            ],
+            $replaceRootStage->getExpression()
+        );
     }
 
     public function testReplaceRootFromBuilder()
@@ -28,14 +37,34 @@ public function testReplaceRootFromBuilder()
                 ->field('product')
                 ->multiply('$field', 5);
 
-        $this->assertSame([['$replaceRoot' => ['product' => ['$multiply' => ['$field', 5]]]]], $builder->getPipeline());
+        $this->assertEquals(
+            [
+                [
+                    '$replaceRoot' => [
+                        'newRoot' => (object) [
+                            'product' => ['$multiply' => ['$field', 5]],
+                        ],
+                    ],
+                ],
+            ],
+            $builder->getPipeline()
+        );
     }
 
     public function testReplaceWithEmbeddedDocument()
     {
         $builder = $this->getTestAggregationBuilder();
         $builder->replaceRoot('$some.embedded.document');
 
-        $this->assertSame([['$replaceRoot' => '$some.embedded.document']], $builder->getPipeline());
+        $this->assertEquals(
+            [
+                [
+                    '$replaceRoot' => [
+                        'newRoot' => '$some.embedded.document'
+                    ]
+                ]
+            ],
+            $builder->getPipeline()
+        );
     }
 }