Use Case

As a... __ driver user
I want... commitTransaction to respect my configured write concern on its initial attempt
So that... the driver respects my replication requirements

User Experience

• Minor bug likely not noticed  by many users, but affects spec-compliance

Dependencies

• Required for NODE-3914

Risks/Unknowns

• Users may notice slight differences in replication behaviour when using transactions if their applications erroneously depended on this overriding behaviour.

Acceptance Criteria

Implementation Requirements

• Update ClientSession.commitTransaction to only override user's configured write concern on retry

Testing Requirements

• Add unit test verifying that commitTransaction respects configured writeConcern on initial attempt

Documentation Requirements

• None

Follow Up Requirements

• None