SPM-1930 will permit sharding with collation.

Queries which specify (a superset of) the shard key in equalities (e.g., sharded on

, query of

) can normally be targeted to a single shard. However, if the query collation does not match the sharding collation, this is not possible.

Prior to the fix for SERVER-94315 QueryPlannerParams::fillOutPlannerParamsForExpressQuery erroneously cleared INCLUDE_SHARD_FILTER in this case, leading to a query executing on multiple nodes, but with no shard filtering, leading to potential duplicate results from orphans.

At the time of SERVER-94315, prior to SPM-1930, the only possible sharding collation was simple. Once SPM-1930 changes this, QueryPlannerParams::fillOutPlannerParamsForExpressQuery must be updated to reflect this.