Remove the unused and dangerous ShareClient mtest option. #2225
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Pull Request Overview
This PR removes the unused and potentially problematic ShareClient mtest option. The feature allowed sharing a single mongo.Client across all subtests, but this interfered with built-in event and command capture capabilities, potentially causing flaky or incorrectly passing tests.
- Removed the
ShareClient()option method from the Options API - Removed the
shareClientfield and all related logic from the test runner - Simplified client lifecycle management by ensuring each subtest always gets its own client
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| internal/integration/mtest/options.go | Removed the ShareClient() method that configured client sharing behavior |
| internal/integration/mtest/mongotest.go | Removed shareClient field, eliminated client sharing logic in test setup and teardown, and simplified client creation flow |
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API Change ReportNo changes found! |
🧪 Performance ResultsCommit SHA: 8e0de1aThe following benchmark tests for version 68f17d3752bc1f0007acc5f4 had statistically significant changes (i.e., |z-score| > 1.96):
For a comprehensive view of all microbenchmark results for this PR's commit, please check out the Evergreen perf task for this patch. |
matthewdale added review-priority-low 
qingyang-hu approved these changes Oct 17, 2025
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Summary
Remove the unused
ShareClientmtest option.Background & Motivation
If
ShareClient=trueis set, mtest will share the samemongo.Clientacross all subtests. There are a number of mtest capabilities, like built-in event capture and command capture that do not work correctly if a shared client is used across multiple subtests, which could lead to difficult to diagnose flaky tests or tests that succeed when they should not. That feature is completely unused, so remove it.