Use Case

As a Node driver engineer,
I want to prevent users from providing sessions from one mongo client to another,
So that we can prevent undefined behavior for our users.

User Impact

• Breaking Change Users passing sessions started on other clients will now have errors thrown from operations

Dependencies

• None

Unknowns

• should we throw an error if the user provides a session from one client to another? or should we silently create an implicit session?
  • errors will make it incompatible with existing code but that's why we are putting this out in a major version
• best way to identify client? - instanceof is brittle, we can generate a unique id and/or use a symbol property; needs to account for legacy client usage
  • what other identifier is there?
  • what problems are there with checking referential equality?

Acceptance Criteria

Implementation Requirements

• when an explicit session is provided to a driver helper, do not attach the session to the operation if it originates from a different mongo client instance
• Check client reference on session against reference passed to executeOperation

Testing Requirements

• Implement prose test 5 from the sessions spec
• Consider additional unit tests for specific error scenarios if prose test is unable to include the correct coverage (message/error type)

Documentation Requirements

• Update startSession API documentation to mention this requirement

Follow Up Requirements

• None