Bulk ops are usually created with mongoc_collection_create_bulk_operation and the bulk's 's client, database, and collection fields are set automatically. But if the bulk op is created with mongoc_bulk_operation_new, these fields must be set explicitly.

If a bulk operation with a NULL client, database, or collection is executed it fails, but it should still initialize "reply" before returning false. Currently it does not initialize "reply" until it has checked these three fields.