test: fix race condition in watch mode tests #61615

mcollina · 2026-02-01T14:47:30Z

Summary

Fixes race condition in watch mode tests that caused intermittent failures.

Problem

The watch mode tests using runInBackground() had a race condition where the stdout "Failed running" message could arrive before stderr was fully collected, causing assertions on stderr content to fail with empty strings.

Solution

When "Failed running" is detected in stdout and stderr is empty, wait for the stderr 'data' event before resolving the promise. This is an event-driven approach rather than timing-based.

Verification

test-watch-mode-restart-esm-loading-error.mjs: 200 runs, 0 failures
test-watch-mode.mjs: 50 runs, 0 failures

Refs: nodejs/reliability#1450

codecov · 2026-02-01T17:53:26Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.74%. Comparing base (27a7bbc) to head (19b861d).
⚠️ Report is 21 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61615      +/-   ##
==========================================
- Coverage   89.76%   89.74%   -0.03%     
==========================================
  Files         673      674       +1     
  Lines      203945   204193     +248     
  Branches    39191    39266      +75     
==========================================
+ Hits       183076   183257     +181     
- Misses      13198    13244      +46     
- Partials     7671     7692      +21

see 41 files with indirect coverage changes

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nodejs-github-bot · 2026-02-01T19:59:28Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71158/

nodejs-github-bot · 2026-02-02T09:38:50Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71163/

The watch mode tests using runInBackground() had a race condition where stdout "Failed running" message could arrive before stderr was fully collected, causing assertions on stderr content to fail with empty strings. Fix by waiting for stderr 'data' event if stderr is empty when "Failed running" is detected. This is an event-driven approach rather than timing-based. Refs: nodejs/reliability#1450

mcollina · 2026-02-02T18:36:46Z

@lpinca @MoLow I need another approval

github-actions · 2026-02-02T18:45:43Z

Failed to start CI

   ⚠  Commits were pushed since the last approving review:
   ⚠  - test: fix race condition in watch mode tests
   ✘  Refusing to run CI on potentially unsafe PR

https://github.com/nodejs/node/actions/runs/21602719238

nodejs-github-bot · 2026-02-02T23:05:21Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71175/

nodejs-github-bot · 2026-02-03T15:03:41Z

Commit Queue failed

- Loading data for nodejs/node/pull/61615
✔  Done loading data for nodejs/node/pull/61615
----------------------------------- PR info ------------------------------------
Title      test: fix race condition in watch mode tests (#61615)
Author     Matteo Collina <matteo.collina@gmail.com> (@mcollina)
Branch     mcollina:fix-flaky-test-watch-mode-restart-esm-loading-error -> nodejs:main
Labels     test, author ready
Commits    1
 - test: fix race condition in watch mode tests
Committers 1
 - Matteo Collina <hello@matteocollina.com>
PR-URL: https://github.com/nodejs/node/pull/61615
Refs: https://github.com/nodejs/reliability/issues/1450
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/61615
Refs: https://github.com/nodejs/reliability/issues/1450
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Sun, 01 Feb 2026 14:47:30 GMT
   ✔  Approvals: 2
   ✔  - Moshe Atlow (@MoLow): https://github.com/nodejs/node/pull/61615#pullrequestreview-3741347346
   ✔  - Luigi Pinca (@lpinca): https://github.com/nodejs/node/pull/61615#pullrequestreview-3738286904
   ✘  Last GitHub CI failed
   ℹ  Last Full PR CI on 2026-02-02T23:05:21Z: https://ci.nodejs.org/job/node-test-pull-request/71175/
- Querying data for job/node-test-pull-request/71175/
✔  Build data downloaded
- Querying failures of job/node-test-commit/85254/
✔  Data downloaded
   ✘  1 failure(s) on the last Jenkins CI run
--------------------------------------------------------------------------------
   ✔  Aborted `git node land` session in /home/runner/work/node/node/.ncu

https://github.com/nodejs/node/actions/runs/21635375308

nodejs-github-bot · 2026-02-03T15:08:05Z

CI: https://ci.nodejs.org/job/node-test-pull-request/71180/

nodejs-github-bot · 2026-02-03T15:46:34Z

Landed in 232dffe

The watch mode tests using runInBackground() had a race condition where stdout "Failed running" message could arrive before stderr was fully collected, causing assertions on stderr content to fail with empty strings. Fix by waiting for stderr 'data' event if stderr is empty when "Failed running" is detected. This is an event-driven approach rather than timing-based. Refs: nodejs/reliability#1450 PR-URL: #61615 Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [node](https://nodejs.org) ([source](https://github.com/nodejs/node)) | patch | `25.6.0` → `25.6.1` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>nodejs/node (node)</summary> ### [`v25.6.1`](https://github.com/nodejs/node/releases/tag/v25.6.1): 2026-02-10, Version 25.6.1 (Current), @aduh95 [Compare Source](nodejs/node@v25.6.0...v25.6.1) ##### Notable Changes - \[[`47df4328d7`](nodejs/node@47df4328d7)] - **build,deps**: replace `cjs-module-lexer` with `merve` (Yagiz Nizipli) [#61456](nodejs/node#61456) ##### Commits - \[[`47df4328d7`](nodejs/node@47df4328d7)] - **build,deps**: replace cjs-module-lexer with merve (Yagiz Nizipli) [#61456](nodejs/node#61456) - \[[`a727054503`](nodejs/node@a727054503)] - **deps**: upgrade npm to 11.9.0 (npm team) [#61685](nodejs/node#61685) - \[[`c78c49ed6b`](nodejs/node@c78c49ed6b)] - **deps**: update amaro to 1.1.7 (Node.js GitHub Bot) [#61730](nodejs/node#61730) - \[[`4790816d9b`](nodejs/node@4790816d9b)] - **deps**: update minimatch to 10.1.2 (Node.js GitHub Bot) [#61732](nodejs/node#61732) - \[[`8c71740e8a`](nodejs/node@8c71740e8a)] - **deps**: update undici to 7.21.0 (Node.js GitHub Bot) [#61683](nodejs/node#61683) - \[[`e559ef6ab1`](nodejs/node@e559ef6ab1)] - **deps**: update googletest to [`56efe39`](nodejs/node@56efe39) (Node.js GitHub Bot) [#61605](nodejs/node#61605) - \[[`300de2bb5a`](nodejs/node@300de2bb5a)] - **deps**: update amaro to 1.1.6 (Node.js GitHub Bot) [#61603](nodejs/node#61603) - \[[`e71e9505ef`](nodejs/node@e71e9505ef)] - **dns**: fix Windows SRV ECONNREFUSED by adjusting c-ares fallback detection (notvivek12) [#61453](nodejs/node#61453) - \[[`439b816bc7`](nodejs/node@439b816bc7)] - **doc**: clarify EventEmitter error handling in threat model (Matteo Collina) [#61701](nodejs/node#61701) - \[[`c1c6641f23`](nodejs/node@c1c6641f23)] - **doc**: mention default option for test runner env (Steven) [#61659](nodejs/node#61659) - \[[`41ec451f98`](nodejs/node@41ec451f98)] - **doc**: fix --inspect security warning section (Tim Perry) [#61675](nodejs/node#61675) - \[[`bb90ef2356`](nodejs/node@bb90ef2356)] - **doc**: document `url.format(urlString)` as deprecated under DEP0169 (René) [#61644](nodejs/node#61644) - \[[`513df82e6f`](nodejs/node@513df82e6f)] - **doc**: update to Visual Studio 2026 manual install (Mike McCready) [#61655](nodejs/node#61655) - \[[`9409d30736`](nodejs/node@9409d30736)] - **doc**: deprecation add more codemod (Augustin Mauroy) [#61642](nodejs/node#61642) - \[[`75a7a67151`](nodejs/node@75a7a67151)] - **doc**: fix grammatical error in README.md (ayj8201) [#61653](nodejs/node#61653) - \[[`821e59e884`](nodejs/node@821e59e884)] - **doc**: correct tools README Boxstarter link (Mike McCready) [#61638](nodejs/node#61638) - \[[`4998f539a0`](nodejs/node@4998f539a0)] - **doc**: update `server.dropMaxConnection` link (YuSheng Chen) [#61584](nodejs/node#61584) - \[[`9383ac4ab7`](nodejs/node@9383ac4ab7)] - **http**: implement slab allocation for HTTP header parsing (Mert Can Altin) [#61375](nodejs/node#61375) - \[[`e90eb1d561`](nodejs/node@e90eb1d561)] - **meta**: persist sccache daemon until end of build workflows (René) [#61639](nodejs/node#61639) - \[[`ade36ac367`](nodejs/node@ade36ac367)] - **meta**: bump github/codeql-action from 4.31.9 to 4.32.0 (dependabot\[bot]) [#61622](nodejs/node#61622) - \[[`26638bd67f`](nodejs/node@26638bd67f)] - **meta**: bump step-security/harden-runner from 2.14.0 to 2.14.1 (dependabot\[bot]) [#61621](nodejs/node#61621) - \[[`eaa9a96cb6`](nodejs/node@eaa9a96cb6)] - **meta**: bump actions/setup-python from 6.1.0 to 6.2.0 (dependabot\[bot]) [#61627](nodejs/node#61627) - \[[`fd98187828`](nodejs/node@fd98187828)] - **meta**: bump cachix/cachix-action (dependabot\[bot]) [#61626](nodejs/node#61626) - \[[`820c1d021c`](nodejs/node@820c1d021c)] - **meta**: bump actions/setup-node from 6.1.0 to 6.2.0 (dependabot\[bot]) [#61625](nodejs/node#61625) - \[[`72a4136bd5`](nodejs/node@72a4136bd5)] - **meta**: bump actions/cache from 5.0.1 to 5.0.3 (dependabot\[bot]) [#61624](nodejs/node#61624) - \[[`e3ef6cb3bc`](nodejs/node@e3ef6cb3bc)] - **meta**: bump peter-evans/create-pull-request from 8.0.0 to 8.1.0 (dependabot\[bot]) [#61623](nodejs/node#61623) - \[[`020a836202`](nodejs/node@020a836202)] - **meta**: bump actions/stale from 10.1.0 to 10.1.1 (dependabot\[bot]) [#61620](nodejs/node#61620) - \[[`0df72f07c8`](nodejs/node@0df72f07c8)] - **meta**: bump actions/checkout from 6.0.1 to 6.0.2 (dependabot\[bot]) [#61619](nodejs/node#61619) - \[[`d147c08b83`](nodejs/node@d147c08b83)] - **module**: do not invoke resolve hooks twice for imported cjs (Joyee Cheung) [#61529](nodejs/node#61529) - \[[`a2843f8556`](nodejs/node@a2843f8556)] - **net**: defer synchronous destroy calls in internalConnect (RajeshKumar11) [#61658](nodejs/node#61658) - \[[`7fb7030781`](nodejs/node@7fb7030781)] - **repl**: fix flaky test-repl-programmatic-history (Matteo Collina) [#61614](nodejs/node#61614) - \[[`d4c9b5cf5b`](nodejs/node@d4c9b5cf5b)] - **sqlite**: avoid extra copy for large text binds (Ali Hassan) [#61580](nodejs/node#61580) - \[[`aa1b3661d9`](nodejs/node@aa1b3661d9)] - **sqlite**: use DictionaryTemplate for run() result (Mert Can Altin) [#61432](nodejs/node#61432) - \[[`9c8ad7e881`](nodejs/node@9c8ad7e881)] - **src**: elide heap allocation in structured clone implementation (Anna Henningsen) [#61703](nodejs/node#61703) - \[[`c4ecfef93d`](nodejs/node@c4ecfef93d)] - **src**: use simdutf for one-byte string UTF-8 write in stringBytes (Mert Can Altin) [#61696](nodejs/node#61696) - \[[`28905b9734`](nodejs/node@28905b9734)] - **src**: consolidate C++ ReadFileSync/WriteFileSync utilities (Joyee Cheung) [#61662](nodejs/node#61662) - \[[`e90cec2f69`](nodejs/node@e90cec2f69)] - **test**: restraint version replacement pattern in snapshots (Chengzhong Wu) [#61748](nodejs/node#61748) - \[[`adce20c0a1`](nodejs/node@adce20c0a1)] - **test**: print stack immediately avoiding GC interleaving (Chengzhong Wu) [#61699](nodejs/node#61699) - \[[`7643bc8999`](nodejs/node@7643bc8999)] - **test**: fix case-insensitive path matching on Windows (Matteo Collina) [#61682](nodejs/node#61682) - \[[`23d1ecf66f`](nodejs/node@23d1ecf66f)] - **test**: fix flaky test-performance-eventloopdelay (Matteo Collina) [#61629](nodejs/node#61629) - \[[`99012a88ed`](nodejs/node@99012a88ed)] - **test**: remove duplicate wpt tests (Filip Skokan) [#61617](nodejs/node#61617) - \[[`a8b32b8ce1`](nodejs/node@a8b32b8ce1)] - **test**: fix race condition in watch mode tests (Matteo Collina) [#61615](nodejs/node#61615) - \[[`086a5a5a25`](nodejs/node@086a5a5a25)] - **test**: update WPT for url to [`e3c46fd`](nodejs/node@e3c46fdf55) (Node.js GitHub Bot) [#61602](nodejs/node#61602) - \[[`f0574fd419`](nodejs/node@f0574fd419)] - **test**: use the skipIfNoWatch() utility function (Luigi Pinca) [#61531](nodejs/node#61531) - \[[`b064ddc221`](nodejs/node@b064ddc221)] - **test**: unify assertSnapshot common patterns (Chengzhong Wu) [#61590](nodejs/node#61590) - \[[`17122e521b`](nodejs/node@17122e521b)] - **test\_runner**: fix test enqueue when test file has syntax error (Edy Silva) [#61573](nodejs/node#61573) - \[[`bad3f02dd9`](nodejs/node@bad3f02dd9)] - **tools**: enforce removal of `lts-watch-*` labels on release proposals (Antoine du Hamel) [#61672](nodejs/node#61672) - \[[`a8f33fd6bd`](nodejs/node@a8f33fd6bd)] - **tools**: use ubuntu-slim runner in meta GitHub Actions (Tierney Cyren) [#61663](nodejs/node#61663) - \[[`c843e447ca`](nodejs/node@c843e447ca)] - **tools**: test `--shared-merve` in `test-shared` workflow (Antoine du Hamel) [#61649](nodejs/node#61649) - \[[`2fedc03f96`](nodejs/node@2fedc03f96)] - **tools**: update OpenSSL to 3.5.5 in `test-shared` (Antoine du Hamel) [#61551](nodejs/node#61551) - \[[`1c1db94670`](nodejs/node@1c1db94670)] - **tools,win**: upgrade install additional tools to Visual Studio 2026 (Mike McCready) [#61562](nodejs/node#61562) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Enabled. ♻ **Rebasing**: Whenever MR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

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sxa mentioned this pull request Feb 4, 2026

Validate testing on AIX 7.3 #61660

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2026-02-10, Version 25.6.1 (Current) #61739

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