As a special case, when transforming a find into an aggregation for a query on a view, the singleBatch option will be dropped if specified when the limit is exactly 1. This allows queries that specify {limit: 1, singleBatch: true} to be sent against a view; without this, the aggregation system would reject the transformed command.

This allows some driver implementations of find_one() to work with views.

Original Description

Drivers that implement the CRUD specification may send the singleBatch option to implement methods like find_one() (for example, PyMongo does this).

This works for the find command, but the aggregation command does not support it. This makes it impossible to perform a find_one on a view namespace, as it translates all query operations into aggregations.