Use Case

As a... Node.js driver user
I want... MongoClient.connect() to throw regardless of configuration if the host does not exist
So that... I can rely on the error to inform my application of the incorrect configuration

User Experience

• What is the desired/expected outcome for the user once this ticket is implemented?
  • The MongoClient.connect function reliably identifies if a host is unable to be connected to

Dependencies

• Compass & Data Explorer connection latency improvements

Risks/Unknowns

• What could go wrong while implementing this change? (e.g., performance, inadvertent behavioral changes in adjacent functionality, existing tech debt, etc)
  • It is a change in behavior, auth-less use is going to run a checkOut when it didn't previously, but now that we've removed "ping" already we will only be running a handshake and populating the pool by 1 so the next operation can use the work done in that step.
  • Additionally, the __skipPingOnConnect flag is still used to bypass the checkOut when we're calling connect for a command (auto-connect) so we don't perform a double checkout.
• Is there an opportunity for better cross-driver alignment or testing in this area?
  • connect is specific to Node
• Is there an opportunity to improve existing documentation on this subject?
  • The connect method should clarify what it represents to succeed or fail in ts-doc

Acceptance Criteria

Implementation Requirements

• Remove the requirement for credentials to run the checkOut "test" for connectivity
• Move the server selection step into the __skipPingOnConnect condition so we don't perform a server selection when auto-connecting (since we will server select for the command)

Testing Requirements

• Verify LB=true and noauth throws if the host does not exist
  • Note: we don't need the topology for this since it is a failure case
• Check that server selection is not doubled for auto-connect

Documentation Requirements

• API Docs on connect

Follow Up Requirements

• None
• if node behavior differs/will differ from other drivers, confirm with dbx devs what standard to aim for and what plan, if any, exists to reconcile the diverging behavior moving forward