Summary

The Evergreen task change_streams_sharded_collections_passthrough does not exist, and hasn't
since the SERVER-84424 "Reorganize change_streams resmoke tasks" refactor (commit
2007e7a5a259, Dec 2023). The resmoke suite itself is intact and runnable locally
(buildscripts/resmoke.py run --suites=change_streams_sharded_collections_passthrough), but no
Evergreen variant schedules it.

History

Three sibling tasks existed together in etc/evergreen.yml since the repo's first Evergreen
config in 2021:

• change_streams_sharded_collections_passthrough
• change_streams_whole_db_sharded_collections_passthrough
• change_streams_whole_cluster_sharded_collections_passthrough

All three were dropped in the same commit during the Dec 2023 reorg. The whole_db and
whole_cluster tasks were later restored, incidentally, as a side effect of unrelated disagg
work in SERVER-124429/SERVER-124494 (April 2025). change_streams_sharded_collections_passthrough
was never restored.

Why this matters

This suite is the only scheduled combination that would run collection-level ($changeStream on
a single collection) watch mode against a multi-shard cluster on a same-version binary set.
change_streams_per_shard_cursor_passthrough uses only 1 shard, and
change_streams_whole_db_sharded_collections_passthrough/..._whole_cluster_sharded_collections_passthrough
force a different watch mode entirely. Today, the only place this topology is exercised in CI is as
a side effect: the multiversion generator (change_streams_sharded_collections_multiversion_gen)
uses this suite as a template, hand-copied into the
{{change_streams_sharded_collections_passthrough_last_

_new_old_old_new}} mapping
files. Any bug specific to this topology can currently only surface as a multiversion BF, which
misdirects triage toward binary-version differences even when the root cause has nothing to do with
version skew (see SERVER-134932).

Ask

Restore change_streams_sharded_collections_passthrough as a scheduled Evergreen task, following
the same pattern used to re-add change_streams_whole_db_sharded_collections_passthrough/
change_streams_whole_cluster_sharded_collections_passthrough in
tasks/resmoke/server_divisions/query/tasks.yml.

Related

• SERVER-134932: a test-correctness bug in this exact topology that this coverage gap let ship silently
• BF-46332: the multiversion BF that surfaced it