Aggregation problem with 'cursor' option

[kalyashka]

What steps will reproduce the problem?

$collection->aggregate($pipeline, ['cursor' => ['batchSize' => 100]]);

What's expected?

Aggregation result

What do you get instead?

yii\base\ErrorException: Undefined index: result in .../vendor/yiisoft/yii2-mongodb/Command.php:734

Additional info

When aggregating with a large number of documents, mongodb produces an error "exception: aggregation result exceeds maximum document size (16MB)". In the mongodb manual, it is recommended that you use a cursor or temporary collection.
As I understand, yii2-mongodb uses a query variant, in which all results are returned as a single document. If this document large enough, mongodb will fail with BSON limit. When setting the 'cursor' option, mongodb returns the documents as an array (cursor). The element 'result' is missing in the results
I propose to enable the 'cursor' option by default and treat the result as a cursor.

Q	A
Yii version	2.0.12
Yii MongoDB version	2.1.4
MongoDB server version	v3.4.8-rc1
PHP version	7.1.1
Operating system	Linux Mint

[klimov-paul]

Resolved by commit 9395f07