Summary

CDRIVER-4255 added assertions for client and pool parameters throughout libmongoc, which subtly broke the PHP driver's use of bulk operations.

The PHP driver allows construction of a BulkWrite object independent of a client. This uses mongoc_bulk_operation_new instead of mongoc_collection_create_bulk_operation_with_opts. Applications then append insert, update, and delete operations to this object. At execution time, the BulkWrite object is passed to a client method (e.g. Manager::executeBulkWrite()), which calls mongoc_bulk_operation_set_client to assign the appropriate client.

The problematic addition in CDRIVER-4255 was adding assertions to mongoc-opts.c.template.