Who contributed to Meta on August 17, 2026?

4 developers shipped this update, including Rob Hogan, Evan Katz, renovate, and SimenB.

What were the notable Meta updates?

fix(jest-haste-map): end the worker farm when the build aborts synchronously, fix(jest-haste-map): attach the watchman client's error listener before use, and [jest-circus, jest-jasmine2] Fix error-handler restore, `--expand` for assert diffs, and generator test context.

Aug 17, 2026

$ the-wire · showcase

JEST TEARS DOWN WORKER FARMS BEFORE THEY LEAK, REACT NATIVE COMPILES PLATFORM CHECKS FASTER

By RepoJournal · Filed 07:05 UTC on August 17, 2026 · About Meta · Composed from the cited sources · methodology

4 people shipped this

SimenB @SimenB 4 cited

Rob Hogan @robhogan 1 cited

Evan Katz @evankatz14 1 cited

renovate @renovate 1 cited

Jest shipped three critical fixes to worker lifecycle management and snapshot handling that prevent resource leaks and test corruption.

SimenB landed a cluster of fixes across jest-haste-map that plug holes in how Jest manages its worker farm [1]. The build now properly ends the worker pool even when `processFile` throws synchronously, not just when workers reject. That's paired with a second fix that attaches watchman's error listener before use [2], preventing daemon startup failures from escaping unhandled. A third fix restores error handlers on the correct process object in jest-circus and jest-jasmine2 [3], where the ambient `process` in the VM sandbox was getting snapshotted instead of the actual parent process. On the React Native side, Rob Hogan merged a Babel plugin that inlines `Platform.OS` and `Platform.select(...)` at the front of RN's preset [4], running before ES modules lower to CommonJS so the optimizer can strip dead branches earlier in the pipeline. Evan Katz added object support to `fontVariationSettings` [5], letting developers pass OpenType axis tags as an object instead of just CSS strings. Jest also refreshed all lock files [6] via Renovate. Simon Bekkhus also fixed snapshot comparison logic [7] so hinted snapshots stay attached to their own test instead of getting reported obsolete and deleted on the next update.

Action items

→ Upgrade Jest to pick up worker farm fixes before your next test run facebook/jest [plan]
→ Update React Native to gain faster Platform inlining in builds facebook/react-native [monitor]

References

[1] fix(jest-haste-map): end the worker farm when the build aborts synchronously ↗ facebook/jest
[2] fix(jest-haste-map): attach the watchman client's error listener before use ↗ facebook/jest
[3] [jest-circus, jest-jasmine2] Fix error-handler restore, `--expand` for assert diffs, and generator test context ↗ facebook/jest
[4] Inline `Platform` within RN’s Babel preset (#57848) ↗ facebook/react-native
[5] Accept object font variation settings (#57929) ↗ facebook/react-native
[6] chore(deps): lock file maintenance ↗ facebook/jest
[7] fix: Keep hinted snapshots with their own test ↗ facebook/jest