feat: return 200 for Bounce collection VersionError

[mantariksh]

Problem

Email notifications arrive at our /emailnotifications endpoint asynchronously, and processing them involves retrieving documents from the Bounce collection. This means that multiple server instances sometimes attempt to access and modify the same Bounce document concurrently, resulting in Mongoose throwing VersionErrors. These errors are caught and HTTP 400 is returned, sometimes resulting in false HTTP 400 alarms.

Solution

Check if the error is a VersionError, and return 200 if it is. The idea here is that we accept the risk of VersionErrors as a limitation of our system, and return an OK response since the error is on our end.

Other improvements

Tests for the Bounce and Verification controllers were updated with hardcoded numbers for HTTP status codes instead of using the http-status-codes package.

[liangyuanruo]

lgtm, but i thought we liked http status code enums