🚨 Breaking Changes

• Don't lookup config file from ancestor directories  -  by @hi-ogawa, Codex and Hiroshi Ogawa in https://github.com/vitest-dev/vitest/issues/10428 (945d9)
• Inline @vitest/runner package, do not publish it anymore  -  by @sheremet-va in https://github.com/vitest-dev/vitest/issues/10511 (6d6e4)
• Allow mutating happy-dom/jsdom window object  -  by @hi-ogawa, Hiroshi Ogawa and Codex in https://github.com/vitest-dev/vitest/issues/10373 (206e8)
• Expose concurrencyId/workerId on TestModule's diagnostics, make id 1-based  -  by @sheremet-va in https://github.com/vitest-dev/vitest/issues/10516 (bdd98)
• browser: Require sessionId for orchestrator html request  -  by @hi-ogawa, Hiroshi Ogawa and Codex in https://github.com/vitest-dev/vitest/issues/10522 (79b7d)
• coverage: Allow thresholds.perFile to accept an object  -  by @vladlenskiy and @AriPerkkio in https://github.com/vitest-dev/vitest/issues/10190 (13b78)

   🚀 Features

• browser: Display nested mark trace in UI  -  by @hi-ogawa, Hiroshi Ogawa and Codex in https://github.com/vitest-dev/vitest/issues/10437 (86ffc)
• cli: Add --repeats CLI option  -  by @todor-a in https://github.com/vitest-dev/vitest/issues/10504 (ee48b)
• coverage: thresholds.autoUpdate to receive previous threshold as argument  -  by @wouterkroes in https://github.com/vitest-dev/vitest/issues/10495 (04f81)

   🐞 Bug Fixes

• Fix mixed stdout/stderr log timestamps in onUserConsoleLog  -  by @Copilot, Hiroshi Ogawa, @hi-ogawa and @sheremet-va in https://github.com/vitest-dev/vitest/issues/10308 (62756)
• Fix importOriginal with optimizer and query import  -  by @davidhwilliams, David Harris, @hi-ogawa, Hiroshi Ogawa and Codex in https://github.com/vitest-dev/vitest/issues/10469 (6a3bb)
• Correct transform time calculation in merged report  -  by @potatomatoooo and @hi-ogawa in https://github.com/vitest-dev/vitest/issues/10570 and https://github.com/vitest-dev/vitest/issues/10578 (b7897)
• browser:
  • Wait for orchestrator readiness before resolving browser sessions  -  by @soconnor-seeq in https://github.com/vitest-dev/vitest/issues/10397 (fe5ed)
  • Wait for iframe tester readiness before preparing  -  by @soconnor-seeq in https://github.com/vitest-dev/vitest/issues/10497 (f2655)
  • Encode iframeId in tester iframe URL  -  by @Pduhard, Pduhard and Claude Opus 4.8 (1M context) in https://github.com/vitest-dev/vitest/issues/10520 and https://github.com/vitest-dev/vitest/issues/10521 (c8bf1)
• coverage:
  • Avoid matching sibling project roots  -  by @innoprej, Shin JaeHee and @AriPerkkio in https://github.com/vitest-dev/vitest/issues/10311 (e30dd)
• mocker:
  • Hoist vi.mock() for vite-plus/test imports  -  by @Brooooooklyn and Claude Opus 4.8 (1M context) in https://github.com/vitest-dev/vitest/issues/10489 (88376)
• pool:
  • Prevent test run hang on worker crash  -  by @jaxalo and @AriPerkkio in https://github.com/vitest-dev/vitest/issues/10543 (40878)
• vitest:
  • Strip non-serializable functions from inline diff config  -  by @DucMinhNe in https://github.com/vitest-dev/vitest/issues/10573 (5b81a)

    View changes on GitHub