[dudaschar]

Description

connectMongoClient merged its result into the caller's clientOptions object. lodash merge() modifies its first argument, so nested options of the caller (for example authMechanismProperties) were changed during connect, and the OIDC callbacks of that connection ended up in them.

This was introduced in #628, which removed the { __skipPingOnConnect: true } object that used to be the merge target. Before that, options were merged into a fresh object.

Callers that keep and reuse their options across connections are affected. In mongosh this breaks keeps authentication state when resetting connection options (OIDC e2e), which fetches a token twice instead of once after bumping to this version of devtools-connect (mongodb-js/mongosh#2899). Compass is not affected, because it deep-clones the options before each call.

The merge now goes into a new object, and a test checks that the options passed in stay unchanged.

Open Questions

Checklist

• I have signed the Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)
• New tests and/or benchmarks are included
• Documentation is changed or added

[Copilot]

🟢 Approval recommended

No active review issues are reported for the change to preserve caller-owned connection options.

No open issues 🎉

What changed in this PR

Fixes a regression introduced in #628 where connectMongoClient mutated caller-owned options, allowing OIDC callbacks to persist across connections when options were reused.

Changes:

• Merges connection options into a fresh object instead of modifying the caller’s object.
• Adds a regression test confirming that OIDC callbacks reach the client while the original options remain unchanged.

File	Description
packages/​devtools-connect/​src/​connect.ts	Uses an empty object as the merge target to preserve caller-owned options.
packages/​devtools-connect/​src/​connect.spec.ts	Tests that merging OIDC callbacks leaves the supplied options unchanged.

_{Review effort: Balanced}

[coveralls]

Coverage is 80.513% — COMPASS-9694-client-mutation into main. No base build found for main.

[coveralls]

Coverage is 80.513% — COMPASS-9694-client-mutation into main. No base build found for main.