fix(jest-haste-map): tolerate a locked file while indexing on Windows by SimenB · Pull Request #16358 · jestjs/jest

SimenB · 2026-08-17T06:34:26Z

Summary

One behavioural fix plus some minor documentation tweaks.

A file another process holds open aborts the crawl on Windows. workerError treated exactly two codes as recoverable:

if (!["ENOENT", "EACCES"].includes(error.code)) {
  throw error;
}

Anything else fails the whole build. On Windows that includes EPERM, which is what git maintenance touching .git/index.lock or .git/objects looks like from the outside — a transient condition that says nothing about the file being indexable. The watchers already survive it: #16295 added isIgnorableFileError for precisely this, but only on the watch path, so a crawl hitting the same file still died.

That helper lived in watchers/common.ts. Both the watch path and the crawl path want it now, so it moves to lib/isIgnorableFileError.ts instead of having lib/FileProcessor.ts reach sideways into watchers/ for an errno predicate. ParcelWatcher and WatchmanWatcher import it from there, and its tests move with it.

EACCES stays a separate condition rather than folding into the helper, because the two callers want different answers: an unreadable file should not tear a watcher down, but during indexing it only means this one file cannot be read. Collapsing them would silently drop EACCES tolerance.

Docs. Three corrections to packages/jest-haste-map/CLAUDE.md, and a comment in walk.ts:

ChangeQueue's 30 ms interval was described as a debounce. It is a periodic flush that emits whatever has queued and does not reset on activity.
The same line merged two distinct guards into one claim. They are separate: a Set of type:path:mtime keys drops duplicates within a frame, and a direct mtime comparison drops change events for files that were only accessed.
Added that ModuleMap's toJSON/fromJSON run for every test worker, not just for the on-disk cache — worth knowing before touching them, as fix(jest-haste-map): restore the nested duplicates index in ModuleMap.fromJSON #16353 showed.
Added that overlapping roots are collapsed by watchman via watch-project but walked separately by find(), so the shared subtree is traversed twice. The map stays correct, and statCache spares some of the repeated lstat calls — best-effort only, since the walks run concurrently and can both miss a path before either caches it. The traversal is always duplicated.
walk.ts: includeDirs and the dir entry kind have no caller and read as dead surface. They are there for symlinked-directory support.

Test plan

lib/__tests__/FileProcessor.test.ts asserts the changed line on both platforms: EPERM is tolerated on win32 and still thrown on linux. It loads FileProcessor through jest.isolateModules with node:os mocked, because the predicate reads the platform once at module load.

That test is the guard. The error-path cases around it — EACCES and ENOENT dropping the file without throwing, an unrecognised code (EISDIR) propagating — behave the same before and after this change, so on their own they left a full revert green. Reverting workerError to the original array check now fails:

● FileProcessor › processFile › on win32, an EPERM worker error keeps the file: false

FULL REVERT:   1 failed, 16 passed
as committed: 17 passed

watchers/__tests__/common.test.ts → lib/__tests__/isIgnorableFileError.test.ts as a rename, keeping its platform matrix (ENOENT everywhere, EPERM only on win32, EACCES never).

yarn jest packages/jest-haste-map

Test Suites: 23 passed, 23 total
Tests:       213 passed, 213 total
Snapshots:   5 passed, 5 total

Also green: yarn lint, yarn typecheck:tests, yarn check-changelog, yarn check-copyright-headers.

The agent notes called ChangeQueue's 30 ms interval a debounce; it is a periodic flush that emits whatever has queued, and it does not reset on activity. The same line merged two distinct guards — the event-key `Set` and the mtime comparison — into one claim. Add the two things a reader has to discover the hard way: that `ModuleMap`'s `toJSON`/`fromJSON` run for every test worker rather than only for the cache, and that overlapping roots are collapsed by watchman but traversed twice by the node crawler. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

`includeDirs` and `WalkEntryKind`'s `dir` case have no caller — `find()` asks for files only — which reads as dead surface. Both exist for symlinked- directory support, where following a link means walking the directory behind it. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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`workerError` treated only `ENOENT` and `EACCES` as recoverable, so an `EPERM` from a file another process holds open failed the whole crawl. The watchers already survive that case via `isIgnorableFileError` (jestjs#16295); file processing did not. Move that helper from `watchers/common.ts` into `lib/`: both the watch path and the crawl path use it now, and `lib/FileProcessor.ts` should not reach sideways into `watchers/` for an errno predicate. `EACCES` stays a separate condition: an unreadable file should not tear a watcher down, but here it only means this one file cannot be indexed. Also correct the agent notes and add two comments from the same review pass: `ChangeQueue`'s 30 ms interval is a periodic flush rather than a debounce, its two dedup guards are distinct, `ModuleMap`'s `toJSON`/`fromJSON` run for every test worker, overlapping roots are collapsed by watchman but walked twice by `find()`, and `walk()`'s `includeDirs`/`dir` surface exists for symlinked directories. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Copilot

Pull request overview

Improves Windows crawl resilience by treating transient EPERM errors as ignorable during indexing.

Changes:

Shares the ignorable-file-error predicate across crawlers and watchers.
Adds worker error-path tests.
Updates haste-map documentation and changelog.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
`CHANGELOG.md`	Records the Windows indexing fix.
`packages/jest-haste-map/CLAUDE.md`	Updates architecture notes.
`packages/jest-haste-map/src/lib/FileProcessor.ts`	Ignores Windows `EPERM` during indexing.
`packages/jest-haste-map/src/lib/__tests__/FileProcessor.test.ts`	Expands worker-error tests.
`packages/jest-haste-map/src/lib/__tests__/isIgnorableFileError.test.ts`	Relocates helper tests.
`packages/jest-haste-map/src/lib/isIgnorableFileError.ts`	Houses the shared error predicate.
`packages/jest-haste-map/src/lib/walk.ts`	Documents directory-entry support.
`packages/jest-haste-map/src/watchers/ParcelWatcher.ts`	Imports the relocated helper.
`packages/jest-haste-map/src/watchers/WatchmanWatcher.js`	Imports the relocated helper.
`packages/jest-haste-map/src/watchers/common.ts`	Removes the former helper definition.

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commit: a618f0f

The added tests covered `EACCES`, `ENOENT` and `EISDIR`, all of which behave identically before and after the change, so reverting the fix outright left them green — the `EPERM`-on-Windows path they exist for was never asserted. Cover both platforms, loading `FileProcessor` through `jest.isolateModules` because the predicate reads the platform once at module load. Also fix two claims found in review. The comment cited `nodejs/node#4337`, which is an HTTP Upgrade change rather than anything about file locking; drop the reference and describe the behaviour on its own. And `statCache` spares repeated `lstat` calls only best-effort — the per-root walks run concurrently and can both miss a path before either caches it, as `walk.ts` already notes. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

SimenB and others added 2 commits August 17, 2026 08:17

SimenB requested a balanced review from Copilot August 17, 2026 06:37

github-actions Bot added the require-changelog If a PR does requires a changelog entry label Aug 17, 2026

Copilot started reviewing on behalf of SimenB August 17, 2026 06:46 View session

Copilot AI reviewed Aug 17, 2026

View reviewed changes

Comment thread packages/jest-haste-map/src/lib/FileProcessor.ts

Comment thread packages/jest-haste-map/src/lib/isIgnorableFileError.ts Outdated

Comment thread packages/jest-haste-map/CLAUDE.md Outdated

SimenB force-pushed the haste-map-docs branch from 8f74dcc to a618f0f Compare August 17, 2026 07:10

SimenB merged commit 1cb03b5 into jestjs:main Aug 17, 2026
105 checks passed

SimenB deleted the haste-map-docs branch August 17, 2026 07:57

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fix(jest-haste-map): tolerate a locked file while indexing on Windows - #16358

fix(jest-haste-map): tolerate a locked file while indexing on Windows#16358
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