ci(scripts): disable V8 Maglev for Windows test children#9131
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pabloerhard merged 2 commits intoJun 30, 2026
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Network-heavy specs intermittently abort with STATUS_STACK_BUFFER_OVERRUN (0xC0000409) on Windows: mocha-run-file forces process.exit() the moment mocha finishes, and that races V8's Maglev teardown while libuv still has in-flight sockets from the spec's real HTTP traffic. The child dies with no stderr and no crash report, so mocha-parallel-files only sees a non-zero exit and reports the file as crashed (e.g. inferred_proxy.spec.js, which is just whichever network spec lost the race that run). --no-maglev sidesteps the faulty tier and can only be passed as a CLI flag, not through NODE_OPTIONS, so the runner injects it into the spawned per-file node processes on win32. Refs: nodejs/node#62260
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Overall package sizeSelf size: 6.42 MB Dependency sizes| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 3.2.0 | 104.26 kB | 843.44 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | dc-polyfill | 0.1.11 | 25.74 kB | 25.74 kB |🤖 This report was automatically generated by heaviest-objects-in-the-universe |
🎉 All green!🧪 All tests passed 🎯 Code Coverage (details) 🔗 Commit SHA: 4540f29 | Docs | Datadog PR Page | Give us feedback! |
BenchmarksBenchmark execution time: 2026-06-29 15:19:38 Comparing candidate commit 4540f29 in PR branch Found 0 performance improvements and 0 performance regressions! Performance is the same for 2255 metrics, 31 unstable metrics.
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #9131 +/- ##
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+ Coverage 93.69% 93.71% +0.02%
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The Windows --no-maglev workaround was appended on every win32 child, but the top-level --maglev/--no-maglev toggle only exists from V8 11 (Node 20). On the supported Node 18 line (V8 10) the flag does not exist, so each spawned spec aborts with `bad option: --no-maglev` (exit 9) before mocha runs, breaking the parallel runner for Windows Node 18. Gate on the running V8 major, which the children inherit via the shared binary.
pabloerhard
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Jul 1, 2026
* ci(scripts): disable V8 Maglev for Windows test children Network-heavy specs intermittently abort with STATUS_STACK_BUFFER_OVERRUN (0xC0000409) on Windows: mocha-run-file forces process.exit() the moment mocha finishes, and that races V8's Maglev teardown while libuv still has in-flight sockets from the spec's real HTTP traffic. The child dies with no stderr and no crash report, so mocha-parallel-files only sees a non-zero exit and reports the file as crashed (e.g. inferred_proxy.spec.js, which is just whichever network spec lost the race that run). --no-maglev sidesteps the faulty tier and can only be passed as a CLI flag, not through NODE_OPTIONS, so the runner injects it into the spawned per-file node processes on win32. Refs: nodejs/node#62260 * ci(scripts): gate --no-maglev by V8 version The Windows --no-maglev workaround was appended on every win32 child, but the top-level --maglev/--no-maglev toggle only exists from V8 11 (Node 20). On the supported Node 18 line (V8 10) the flag does not exist, so each spawned spec aborts with `bad option: --no-maglev` (exit 9) before mocha runs, breaking the parallel runner for Windows Node 18. Gate on the running V8 major, which the children inherit via the shared binary.
rochdev
pushed a commit
that referenced
this pull request
Jul 2, 2026
* ci(scripts): disable V8 Maglev for Windows test children Network-heavy specs intermittently abort with STATUS_STACK_BUFFER_OVERRUN (0xC0000409) on Windows: mocha-run-file forces process.exit() the moment mocha finishes, and that races V8's Maglev teardown while libuv still has in-flight sockets from the spec's real HTTP traffic. The child dies with no stderr and no crash report, so mocha-parallel-files only sees a non-zero exit and reports the file as crashed (e.g. inferred_proxy.spec.js, which is just whichever network spec lost the race that run). --no-maglev sidesteps the faulty tier and can only be passed as a CLI flag, not through NODE_OPTIONS, so the runner injects it into the spawned per-file node processes on win32. Refs: nodejs/node#62260 * ci(scripts): gate --no-maglev by V8 version The Windows --no-maglev workaround was appended on every win32 child, but the top-level --maglev/--no-maglev toggle only exists from V8 11 (Node 20). On the supported Node 18 line (V8 10) the flag does not exist, so each spawned spec aborts with `bad option: --no-maglev` (exit 9) before mocha runs, breaking the parallel runner for Windows Node 18. Gate on the running V8 major, which the children inherit via the shared binary.
rochdev
pushed a commit
that referenced
this pull request
Jul 2, 2026
* ci(scripts): disable V8 Maglev for Windows test children Network-heavy specs intermittently abort with STATUS_STACK_BUFFER_OVERRUN (0xC0000409) on Windows: mocha-run-file forces process.exit() the moment mocha finishes, and that races V8's Maglev teardown while libuv still has in-flight sockets from the spec's real HTTP traffic. The child dies with no stderr and no crash report, so mocha-parallel-files only sees a non-zero exit and reports the file as crashed (e.g. inferred_proxy.spec.js, which is just whichever network spec lost the race that run). --no-maglev sidesteps the faulty tier and can only be passed as a CLI flag, not through NODE_OPTIONS, so the runner injects it into the spawned per-file node processes on win32. Refs: nodejs/node#62260 * ci(scripts): gate --no-maglev by V8 version The Windows --no-maglev workaround was appended on every win32 child, but the top-level --maglev/--no-maglev toggle only exists from V8 11 (Node 20). On the supported Node 18 line (V8 10) the flag does not exist, so each spawned spec aborts with `bad option: --no-maglev` (exit 9) before mocha runs, breaking the parallel runner for Windows Node 18. Gate on the running V8 major, which the children inherit via the shared binary.
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Summary
Windows test jobs intermittently fail with a crashed spec file and exit code
3221226505(0xC0000409/STATUS_STACK_BUFFER_OVERRUN) — no stderr, nocrash report, no mocha failure.
scripts/mocha-run-file.jsforcesprocess.exit()as soon as mocha finishes, and on Windows that races V8'sMaglev teardown while libuv still has in-flight sockets from a spec's real HTTP
traffic. The runner only sees a non-zero child exit and reports the file as
crashed. The file in the originating run was
inferred_proxy.spec.js, but it isjust whichever network-heavy spec lost the race — its plugin logic is sound.
scripts/mocha-parallel-files.jsnow injects--no-maglevinto the spawnedper-file
nodeprocesses onwin32only, sidestepping the faulty tier.Why
--no-maglevis a V8 flag that cannot be set throughNODE_OPTIONS, so it hasto be a direct CLI argument on each spawned child — the parent runner can't
forward it any other way. The crash is upstream (nodejs/node#62260, still open);
this is a stop-gap until that lands, gated to Windows where the abort occurs.
Test plan
tracing-windows, and other Windows suites routedthrough
mocha-parallel-files.js) stay green across reruns.node scripts/mocha-parallel-files.js --timeout 30000 -- "packages/dd-trace/test/plugins/util/inferred_proxy.spec.js"passes locally with no flag added.Refs: nodejs/node#62260