Several JS test libraries currently duplicate an inline check to detect whether the current test is running in a multiversion suite. The canonical form lives inside jsTestOptions() in the mongo shell, where it is used only locally to gate OTEL tracing:

const isMultiversion =
    TestData.useRandomBinVersionsWithinReplicaSet || TestData.mixedBinVersions || TestData.mongosBinVersion;

The same idea is re-implemented (with slightly different flag sets) across several libraries:

• ReplSetTest dbHash comparison — checks useRandomBinVersionsWithinReplicaSet, mongosBinVersion, multiversionBinVersion, mixedBinVersions
• catalog list operations consistency validator — checks useRandomBinVersionsWithinReplicaSet, multiversionBinVersion
• raw operation utils — same flags as above
• shard transition util — only checks useRandomBinVersionsWithinReplicaSet

The closest thing to a reusable helper today is the private _clusterVersionInfo() method on ShardingTest, which returns {{

}} but is not exposed outside the class.

Proposal

Add a single exported helper (e.g. isMultiversionSuite()) in a shared lib such as jstests/libs/ — or expose the existing computation from the mongo shell — and replace the inline checks in the files listed above. This would:

1. Give tests one canonical way to detect multiversion execution.
2. Eliminate the inconsistency where some callers include multiversionBinVersion / mongosBinVersion and others do not.
3. Make future additions to the set of multiversion flags a single-site change.