Proposal

Include the version of crypt_shared / mongocryptd in the error produced by libmongocrypt.

Background & Motivation

crypt_shared / mongocrypd produces an error on unrecognized MQL. A user connected to a new mongod / mongos server may expect new MQL to work, but get an error from crypt_shared / mongocrypd failing to process the command.

Example scenario (see mongocryptd-too-old.py for a working example):

• Use mongod 7.0 (supports $median)
• Use mongocryptd 6.0 (does not support $median)
• Gets error: Invalid $project :: caused by :: Unknown expression $median

Consider prepending the source of this error to the message, e.g. "mongocryptd 6.0.9". That may give users a hint that their crypt_shared / mongocryptd component is too old.

Quoting conversation with erwin.pe@mongodb.com:

during a sync with product, the topic of programmatically ensuring that the mongo_crypt_v1.so and mongocryptd versions are compatible with the version of mongod/s that the client is connected to came up for discussion. The main motivation is that there have been several instances where people got tripped up on having a mongocryptd/shared version that don't support the newer query expressions, but got no clear indication of the root cause of the issue.