Summary

The spec tests for change streams don't cover any case using the updateLookup option.  This was discovered accidentally in the Rust driver when a doc example failed to run due to a mismapped field name; the tests should cover it to prevent other drivers from doing the same.

Motivation

Who is the affected end user?

Application developers.

How does this affect the end user?

Depending on language and driver behavior, if this bug exists in other drivers it could cause the field to be ignored or cause watch calls to fail.

How likely is it that this problem or use case will occur?

Unlikely; field naming conventions are well-established.

If the problem does occur, what are the consequences and how severe are they?

Missing update data or a call failure, depending on driver implementation.  Not severe; failure in either case will be obvious and non-destructive.

Is this issue urgent?

No.

Is this ticket required by a downstream team?

No.

Is this ticket only for tests?

Yes.