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WalkthroughChangesThe recursive deletion paths now share platform-aware directory opening. Traversal treats concurrent entry removal, directory disappearance, and completed fallback deletion as successful outcomes. Regression tests cover simulated races and concurrent removals. Recursive delete handling
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Updated 9:01 PM PT - Aug 21st, 2026
❌ @robobun, your commit c8d684f has 1 failures in
🧪 To try this PR locally: bunx bun-pr 39710That installs a local version of the PR into your bun-39710 --bun |
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The earlier review items are addressed in 6deaf1e / 4744bfa: dt_delete_file now maps the macOS lstatat→ENOENT race, Dir::delete_tree's child-open and initial-subpath sites go through openat_dir_for_delete_tree, that helper now delegates to open_dir_at_windows_a, and the shim links -ldl. One inline nit remains on the third open site in Dir::delete_tree (the need_to_retry re-open). The shell rm builtin sibling (src/runtime/shell/builtin/rm.rs) is still on the unmapped path — fine to leave for a follow-up, but worth a note in the PR description per the earlier comment.
Extended reasoning...
4744bfa addressed all four items from the previous review round. Re-checked each against the current diff: the macOS lstatat disambiguation now returns Err(E::ENOENT) when the entry vanished (so the unshimmed concurrency test no longer depends on #37155), openat_dir_for_delete_tree is a one-line delegation to open_dir_at_windows_a, and two of the three Dir::delete_tree open sites use it. The remaining nit (need_to_retry re-open at dir.rs:~220) is the same cfg-split pattern applied one more time; not a regression. Not approving because this is cross-platform race handling in the recursive-delete path with Windows-specific NT-status mapping that CI has to validate — a human look is still appropriate.
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I reviewed this PR across five rounds; every prior finding (-ldl on the shim, the macOS lstatat→ENOENT fall-through, routing all three Dir::delete_tree open sites plus the retry re-open through the shared helper, delegating to open_dir_at_windows_a, and making the helper cross-platform) has been addressed, and this pass found no new issues. Because the change touches cross-platform filesystem deletion — the NT-status mapping in open_dir_at_windows_nt_path and Dir::delete_tree used by bun install/bunx/upgrade — a human look would still be worthwhile.
What was reviewed:
- The three new ENOENT-skip arms in
zig_delete_tree(child-open, min-stack hand-off, file unlink) mirror what the min-stack variant already tolerates. openat_dir_for_delete_tree's non-Windows arm is behavior-equivalent to the old inlinedt_open_dir(only addsO_CLOEXEC, whichdir.rsalready passed).- The LD_PRELOAD shim's interposition probe and the 15-deep chain that forces the min-stack fallback — the test fails loudly if interposition breaks.
Extended reasoning...
Overview
The PR fixes a race in recursive fs.rm/rmSync where a concurrent deleter (or an AV scanner/indexer holding a transient handle on Windows) causes the delete-tree walk to abort mid-tree instead of continuing. Four files: src/runtime/node/node_fs.rs (three new ENOENT-skip arms in zig_delete_tree, and the macOS EPERM-disambiguation lstatat now maps its own ENOENT correctly), src/sys/lib.rs (new WindowsOpenDirOptions.delete_pending_is_enoent flag consumed in open_dir_at_windows_nt_path, and a cross-platform openat_dir_for_delete_tree wrapper), src/sys/dir.rs (all three dir-open sites in Dir::delete_tree routed through the new helper), and two tests in test/js/node/fs/fs.test.ts (a deterministic LD_PRELOAD shim test on glibc and an unshimmed 8-way concurrency test on all platforms).
Security risks
None identified. The change loosens error handling only for ENOENT (and Windows DELETE_PENDING/FILE_DELETED mapped to ENOENT) during a recursive delete the caller already asked for — an entry that vanished mid-walk is exactly the outcome the caller wanted. The new option flag defaults to false and is opt-in per call site, so no other open_dir_at_windows_nt_path caller changes behavior. No path-traversal, no untrusted-input parsing, no auth/crypto.
Level of scrutiny
Medium-high. The core node:fs change is small and well-argued, but it also changes sys::Dir::delete_tree, which ~20 callers across bun install, bunx, upgrade, link/unlink, and tarball extraction share. On non-Windows the helper is a straight openat_a with the same flag set those sites already passed (plus O_CLOEXEC, which they already had), so it is behavior-preserving there; the Windows change is a strict widening of the ENOENT arm those sites already handle. The Windows path can only be verified in CI (the author flagged this), and the concurrency test is probabilistic on the Windows lane.
Other factors
This PR has iterated through five fix commits addressing every inline finding from prior review rounds, ending with 009478c which made openat_dir_for_delete_tree cross-platform per the last suggestion. Two comment-cop bot flags remain open on a 2-line comment at node_fs.rs:9659 and a 4-line doc comment at lib.rs:7039 — both look like normal-length comments, not paragraph-long workaround justifications. Given the cross-platform reach into shared syscall wrappers and Dir::delete_tree, a maintainer sign-off is appropriate rather than an automated approval.
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Tested this branch on Linux x64 against two concurrent deleters.
The remaining exit is the directory iterator. On Linux, Treating that ENOENT as the end of the directory closes it. The
rm-vs-rm.mjsimport fs from "node:fs";
import os from "node:os";
import path from "node:path";
import { spawn } from "node:child_process";
const ROUNDS = 20, DIRS = 16, FILES = 500;
const deleter = `
const fs = require("node:fs");
const [root, dirs] = process.argv.slice(1);
fs.writeSync(1, "ready\\n");
while (fs.existsSync(root))
for (let i = 0; i < dirs; i++)
try { fs.rmSync(root + "/d" + ((i * 7) % dirs), { recursive: true, force: true }); } catch {}
`;
const base = fs.mkdtempSync(path.join(os.tmpdir(), "rm-vs-rm-"));
let leftBehind = 0;
for (let round = 0; round < ROUNDS; round++) {
const root = path.join(base, `root-${round}`);
for (let d = 0; d < DIRS; d++) {
fs.mkdirSync(path.join(root, `d${d}`), { recursive: true });
for (let f = 0; f < FILES; f++) fs.writeFileSync(path.join(root, `d${d}`, `f${f}`), "");
}
const child = spawn(process.execPath, ["-e", deleter, root, String(DIRS)], { stdio: ["ignore", "pipe", "inherit"] });
await new Promise(resolve => child.stdout.once("data", resolve));
fs.rmSync(root, { recursive: true, force: true });
if (fs.existsSync(root)) {
leftBehind++;
console.log(`round ${round}: rmSync returned, root still exists`);
}
child.kill("SIGKILL");
await new Promise(resolve => child.once("exit", resolve));
}
fs.rmSync(base, { recursive: true, force: true });
console.log(`root left behind in ${leftBehind}/${ROUNDS} rounds`);Results on Linux x64:
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…opened (#40000) ### Problem - `fs.readdirSync(root, { recursive: true })` throws `ENOENT: no such file or directory, scandir '<root>'` when another process removes a subdirectory during the call. `root` still exists. `fs.promises.readdir` rejects too. - The walk skips a subdirectory whose open fails with ENOENT, ENOTDIR or EPERM. A removal that lands after the open surfaces as ENOENT from `getdents64` instead. Both walkers in `src/runtime/node/node_fs.rs` returned that error. ### Fix - One predicate, `readdir_skips_subdir`, now covers the open and the read of a subdirectory in both walkers. A tolerated read error ends that subdirectory. Root errors and other errnos are returned as before. - Matches node for this race. libc's `readdir(3)` reports this ENOENT as the end of the directory, so node lists the subdirectory as empty and continues. bun reads with the raw syscall and saw the errno. - The open arm is unchanged. Only timing decides which syscall sees the removal, so the read arm uses the same set. - Verified: the new test in `test/js/node/fs/fs.test.ts`. Its four walk variants fail on bun 1.4.0. Other suites: see the notes. ### Background - Each directory below the root is opened with `openat(root_fd, relative)` and read with `getdents64`, in one loop (sync) or in one subtask per directory (async). Any subtask error rejects the promise. - On Linux, `getdents64` on a directory removed after its open fails with ENOENT (`IS_DEADDIR` in fs/readdir.c). glibc, and the FreeBSD arm of bun's iterator, turn this into end of directory. The Linux arm does not. - The test preloads a shim on libc's `syscall()`, bun's route to `getdents64`. It really removes two marked directories during the walk, and the test checks that both are gone. glibc only. <details><summary>Notes</summary> - Origin: found while #39710 was verified. Recursive rm has the same gap on its own walk and is handled in that thread. The original observation: a root with 128 subdirectories, a second process unlinking their files and removing them, and `readdirSync(root, { recursive: true })` in a loop in the main process. It fired about once in a few hundred iterations. - Repro without the race: the shim from the test, run against bun 1.4.0. Sync: `ENOENT scandir 'root-sync'`. Async: `ENOENT getdents64 'root-async/vanish-mid-read'`. - Raw syscall against libc, same machine (kernel 6.17, glibc 2.41), directory opened and then removed: `getdents64` returns -1 with ENOENT on overlayfs and on tmpfs. glibc's `readdir(3)` on the same state returns NULL with errno 0, that is, end of directory. The kernel side is generic: `vfs_rmdir` sets `S_DEAD` on the inode, and `iterate_dir` returns ENOENT for it before any filesystem code runs. So the errno does not depend on the filesystem, only on whether the reader uses libc or the raw syscall. A probe through Python or any other libc reader shows an empty listing for this reason, not an error. - Node, observed: `fs.opendirSync(dir)`, then `rmdirSync(dir)`, then `dir.readSync()` returns `null` (end of directory) on node v26.3.0. bun returns `ENOENT scandir` there before and after this change. That `opendir` path and a root removed after its open are the same libc difference, on a different consumer of the iterator. This change leaves them alone: it would mean a change to the Linux arm of the iterator, which every directory walker in bun shares (readdir, opendir, cp, rm, glob, the shell builtins). The rm side of that is in flight in #39710. That alignment is a separate change if wanted. - Node with the subdirectory removed before node opens it (a shim on `scandir(3)`): `readdirSync` and `fs.promises.readdir` both throw `ENOENT scandir 'root/vanish-before-read'`. bun skips the subdirectory there, and did so before this change. This change does not widen that difference, it only makes the read step behave like the open step. - The shim removes one directory before its first read (the read fails at once) and one after its first read handed out an entry (the end-of-directory read fails). The `withFileTypes` variants cover the `dirent_path_prev` release on the new `break` path. They pass under the ASAN debug build. - Why the message named the root: `NodeFS::readdir` rebuilds every error of the sync form as `scandir` on the root argument. That is unchanged here and is what #38017 changes. - Unchanged: EACCES, EINVAL, ELOOP, EIO and every other errno still fail the call, from the open and from the read. The root cases in the new test pass before and after this change on purpose. They pin that only subdirectories are skipped. - Open PRs on the same lines, all independent of this one: #38017 (name the failing subdirectory), #37988 (syscall name of the async forms), #33432 (add ELOOP to the skipped set, which becomes a one-line change to the predicate). The test asserts `code` and `path` only, so #37988 and #38017 do not change its expectations. - The walkers are shared by all platforms, so the predicate applies on macOS and Windows too. What those kernels report for a removed open directory was not checked here. The test runs on Linux glibc only. - Suites run with the debug build: all of `test/js/node/fs/fs.test.ts`, `readdirSync-recursive-error-leak.test.ts`, `dir.test.ts`, `fs-path-length.test.ts`, node's `test-fs-readdir*.js`, regression tests 17793, 24007, 28159, 29585. `test/regression/issue/10139.test.ts` (a `bun build` of a 128 MB asset with a 5 s budget) times out in this container with the debug build. It does not use recursive readdir. </details> <!-- robobun:evidence:begin --> --- **no test proof** · iteration 0 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/node/fs/fs.test.ts <!-- robobun:evidence:end -->
… macOS lstat race Co-authored-by: Sankalp Thakur <31366524+sankalpsthakur@users.noreply.github.com>
009478c to
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CI on the current head is green for this diff. The remaining failures are pre-existing or flaky on unrelated lanes: bun-audit.test.ts (fails on main), bun-inspector-protocol.test.ts (passed when run alone), worker-late-completion.test.ts (passed on retry). The earlier run failed on GitHub API 504s in the install tests, also unrelated. |
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In `@test/js/node/fs/fs.test.ts`:
- Around line 5962-5963: Update the fixture entries around child.js to use
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import so the test fixture uses ESM syntax.
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I reviewed the current head and found no new issues — all prior review feedback (macOS lstat-ENOENT race, the third dir-open site in Dir::delete_tree, the cross-platform openat_dir_for_delete_tree helper, the iterator-ENOENT arms, and both interposition probes) has been addressed. Given this touches cross-platform delete-tree syscall handling shared by node:fs and sys::Dir::delete_tree (install/bunx/tarball extraction), a human look is still worthwhile.
What was reviewed:
- The new ENOENT-skip arms at every walk site (child open, unlink, min-stack hand-off, iterator read) in both
zig_delete_treevariants andsys::Dir::delete_tree— verified each falls through to an rmdir/pop that already tolerates ENOENT. openat_dir_for_delete_tree: the non-Windows arm preserves the exact prior flag set (O_DIRECTORY|O_RDONLY|O_CLOEXEC|O_NOFOLLOW); the Windows arm delegates toopen_dir_at_windows_awith the newdelete_pending_is_enoentfield, and the status check sits beforefrom_nt_statusso only DELETE_PENDING/FILE_DELETED are remapped.- The macOS
dt_delete_filelstat fallthrough: other lstat errors still surface the originalunlinkaterrno, so real EPERM/EACCES are not masked. - The LD_PRELOAD shim test: both hooks now probed; the concurrency test runs on all platforms and the macOS EPERM path is covered by the
dt_delete_filechange.
Extended reasoning...
Overview
This PR fixes recursive fs.rm/fs.rmSync (and the shared sys::Dir::delete_tree) to keep walking when a concurrent deleter removes entries out from under it, instead of aborting mid-tree. It touches four files: src/runtime/node/node_fs.rs (the zig_delete_tree walk and its min-stack twin, plus the macOS dt_delete_file EPERM disambiguation), src/sys/dir.rs (the Dir::delete_tree walk used by install/bunx/tarball extraction), src/sys/lib.rs (a new WindowsOpenDirOptions.delete_pending_is_enoent flag and a cross-platform openat_dir_for_delete_tree helper), and test/js/node/fs/fs.test.ts (an LD_PRELOAD shim test that deterministically simulates the race, plus an unshimmed 8-way concurrent-rm test).
Security risks
None identified. The change widens ENOENT tolerance inside a delete walk — the only new behavior is "skip an entry that already vanished" or "treat a delete-pending Windows dir as gone," both of which are strictly what the caller asked for (rm -rf). No new user input parsing, no path handling changes, no privilege boundaries crossed. The delete_pending_is_enoent flag defaults to false and is set only by the new delete-tree helper, so other open_dir_at_windows_nt_path callers are unaffected.
Level of scrutiny
Moderate-to-high. This is production-critical filesystem code shared across node:fs, the package manager, and tarball extraction, with three distinct platform-specific error-mapping paths (Windows NT status → ENOENT, macOS BSD unlinkat EPERM → lstat ENOENT, Linux getdents on a dead dir → end-of-iteration). Each ENOENT arm is individually simple, but the correctness argument depends on the surrounding pop/rmdir already tolerating ENOENT — which I verified at each site. The non-Windows arm of openat_dir_for_delete_tree adds O_CLOEXEC relative to what dt_open_dir previously passed, but that is benign (and matches what Dir::delete_tree already used). A human should still confirm the Windows delete_pending_is_enoent mapping and the shared Dir::delete_tree change do not regress install/extraction on Windows CI.
Other factors
The PR has been through several review rounds; every prior finding I raised is marked resolved and reflected in the current diff (the getdents64 probe from my last comment is now present as bun-shim-probe-getdents-dir). robobun's rm-vs-rm.mjs experiment confirmed the iterator-ENOENT fix, and the author reports CI green with only unrelated flakes. The shim test is glibc-gated with interposition probes for both hooked symbols, so it fails loudly rather than vacuously if either hook stops interposing.
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Problem
fs.rmandfs.rmSyncwithforce: truereject when they race another deleter of the same tree. On Windows 1.3.14 the error isEFAULT: bad address in system call argument, rm <path>, on current main EPERM. 8 concurrentrm(dir, { recursive: true, force: true })over 1000 rounds on Windows: about 2% of the 8000 calls reject. Node: 0.zig_delete_tree,src/runtime/node/node_fs.rs) stops on the first error from a child entry. When another deleter wins, the child dir open reportsSTATUS_DELETE_PENDING. The Win32 conversion turns that into EPERM (on 1.3.14 it fell through the old errno table to EFAULT). A child that is fully gone (ENOENT) also stopped the walk.force: trueswallowed that, so the call resolved while the rest of the tree was still on disk.Fix
sys::openat_dir_for_delete_tree(src/sys/lib.rs). On Windows it reportsSTATUS_DELETE_PENDINGandSTATUS_FILE_DELETEDas ENOENT.DeleteFileBunalready treats those statuses as success on the unlink side.sys::Dir::delete_tree(bun install, bunx, tarball extraction) uses the same open.dt_delete_filedisambiguates the BSDunlinkatEPERM with an lstat. When that lstat reports ENOENT, the entry is gone and the walk now sees ENOENT instead of the stale EPERM. This is the race fromfs.rm(path, { recursive: true, force: true })rejects withEFAULTwhen concurrent calls race on the same directory #36984 (same approach as fix(fs): concurrent recursive force rm races should not reject with EFAULT #37155, credited in the commit).test/js/node/fs/fs.test.ts(the new shim test fails on main). The Windows race repro rejects 0 of 17600 calls after the fix, about 300 before. Also fullfs.test.tson Linux and Windows,rm-windows-ntstatus.test.ts, and the node parallel fs-rm tests.Background
zig_delete_treeis the port of Zig'sstd.fs.deleteTree: readdir each directory, unlink files, recurse into subdirectories through a 16-slot stack, rmdir on pop. The sibling min-stack variant (used past depth 16) already tolerated ENOENT on child entries.STATUS_DELETE_PENDING.RtlNtStatusToDosErrorgives ERROR_ACCESS_DENIED), which maps to EPERM.Fixes #39708
Notes
fs.rm(path, { recursive: true, force: true })rejects withEFAULTwhen concurrent calls race on the same directory #36984 (8 concurrentrmof one dir, 1000 rounds). Windows x64, bun 1.3.14 release: 558 EACCES + 1 EFAULT. Current main (debug): 96 to 172 EPERM per run. After the fix: 0 rejections in 17600 calls. A backtrace probe indt_errshowed every rejection came from the child/initial dir open, and an NT-status probe showedSTATUS_DELETE_PENDING(0xC0000056) on every EPERM.rmSyncon a loaded CI runner. An external handle holder (AV scanner, indexer) creates the same transient statuses that a secondrmdoes.force: truemasked the mid-walk ENOENT bail. The observable defect there was the leftover tree.dt_delete_filehunk here takes the same approach (credited in the commit). node:fs: recursive rm passes through unmapped errnos instead of reporting EFAULT #35749 removes the_ => EFAULTfallthrough tables. node:fs: non-recursive rm treats a file that is already being deleted as gone #38550 covers the non-recursivermbranch.rmbuiltin keeps its current behavior. Its dir open goes throughshell_openat, which other builtins share, so the same-class fix there is left for a follow-up.need_to_retryrmdir loop keeps its unbounded structure. That matches the min-stack variant and the Zig original.no test proof · iteration 3 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/js/node/fs/fs.test.ts