[robobun]

Related to #46583

Problem

• bun lint --staged prints No staged files to lint and exits 0 for a changed file behind a directory symlink. --changed (No changed files to lint) and bun fmt do the same.
• Git names a file by its real path. Files::as_listed (src/lint/driver/git.rs:366) used the path as the run spells it.

Fix

• The file search reports the directory symlinks it went through. Only then does as_listed resolve a directory.
• --staged gives its index texts to the import rules and the type checker under those paths too.
• --fix writes a file that has two paths from the path git has.
• Verified: test/cli/lint/git.test.ts (17 new tests, 14 fail on main). Also lint.test.ts, config-files.test.ts, format.test.ts. Self-reviewed: 39 concerns raised, 36 addressed. Not done: a Disk::read fallback and two test rows (Notes).

Background

• The flags narrow a run to the files git lists. The lint walk follows a directory symlink and keeps its name.
• No user reported this. bun lint, bun fmt: the first run, oxlint's order, Prettier's Tailwind plugin, native JavaScript plugins, a faster Bun.Glob #45043 fixed the same symptom for a link above the repository (reply). An ordinary run still resolves nothing.
• Considered a real-path fallback in Disk::read. bun check and bun build --check read through it too.

Downsides

• At the root, a file behind a followed link is reported under each path.
• A symlink, a file argument, or a bun fmt argument other than . adds 0 to 199 realpath calls for 2,000 files. Release text: +7,936 bytes.
• Not fixed: a link to a file, a deleted staged file behind a link, an import through another symlink.

Notes

Who hits this. On main, three kinds of run miss the file:

• A run from a package directory that links a shared directory: No staged files to lint, exit 0.
• A link, or a path through one, as an argument, for bun lint and bun fmt.
• A run at the repository root where a config applies only on the path through the link: No problems in 1 file.

At the root without such a config, main reports the file under git's path and exits 1. Git has no entry for a path beyond a symlink (git add packages/a/tests/shared/limits.ts fails with is beyond a symbolic link), so main's answer is git's answer. With this PR the flags narrow the run and do not change which paths it lints.

Repro.

git init -q -b main . && mkdir -p shared-tests packages/a/tests
echo '{"name":"root","type":"module"}' > package.json
echo '{"name":"a","type":"module"}' > packages/a/package.json
echo 'export const limit = 1;' > shared-tests/limits.ts
ln -s ../../../shared-tests packages/a/tests/shared
git add -A && git -c user.name=t -c user.email=t@example.com commit -q -m init
printf 'debugger;\n' >> shared-tests/limits.ts
cd packages/a
bun lint                 # exit 1: no-debugger at tests/shared/limits.ts:2:1
bun lint --changed=HEAD  # main: "No changed files to lint", exit 0
git add -A && bun lint --staged  # main: "No staged files to lint", exit 0

Mechanism.

• Loader::links and Loader::named_a_file are filled by the file search, like searched_from. The search already resolves each starting directory and each symlink it follows, so this costs no system call. Files::searched takes them before the run filters its files.
• Files::resolves starts as true. A search that went through no symlink and named no file turns it off. Then as_listed returns every path as it is, as main does for a path in the work tree.
• If it is on, as_listed first takes a path that is listed or is an index entry as it is. For any other path it resolves the directory, once for each directory. has only asks for a file that is named like a listed one.
• already_read has the index texts for code that follows imports. It now also has each text under the path through each symlink that the run went through, if that path leads to the same directory. The module graph gets the texts after the search (Graph::provide). Store::provide asserts in debug builds that no rule has read the store yet.
• bun fmt follows no symlink in a search and resolves no argument, so any argument other than the working directory turns resolves on.
• --fix first writes the results whose path is the one git has. A result with another path to the same file then finds the file written and is skipped, as in a run without the flag. There, the threads decide which path writes.
• A staged file whose directory became a symlink is found twice, on disk through the link and as a file that is not on disk. It is now linted once.

What does not change.

• A link to a file does not count as the file. That is the rule of bun lint, bun fmt: the first run, oxlint's order, Prettier's Tailwind plugin, native JavaScript plugins, a faster Bun.Glob #45043. Git has its own entry for such a link.
• Git lists a new or retargeted link as a link, which is skipped. So a commit that only adds a link to a directory selects nothing below it.
• bun fmt follows no link in a search and, without .oxfmtrc.json, rejects a link as an argument.
• A path that git has wins as spelled. After git add l/f.js && mv l d && ln -s d l, bun lint --staged l exits 1 with the staged text.
• No method of git::Files that other code calls changes. The diff applies to the current head of bun check: TypeScript 7.1 #46383 (5ce9919), and cargo check -p bun_lint_driver -p bun_lint_graph passes on the result.

Measurements. Debug (ASan) builds for the counts, release builds for instructions and size. Merge base 6292c65 against this PR, x86_64 Linux. Counts are for the bun process without its git children: an LD_PRELOAD counter for libc realpath, a ptrace counter for system calls, perf_event_open for instructions:u, ASan's exit statistics for allocations. strace, perf, valgrind and bloaty are not installed in the build container.

2,000 files in 200 directories, --list-files --threads=1. "Shared" means that every directory has a file with the staged file's name.

Run	main	PR
bun lint, bun fmt, no flag	newfstatat 2,186 and 2,018	the same, all counts
lint --staged, fmt --staged, fmt --staged ., lint --staged src, one staged file, shared	newfstatat 2,217 / 2,049 / 2,049 / 2,238, realpath 1 / 0 / 0 / 1	the same, all counts
2,200 files: a staged file with a unique name, and an unstaged change in an index.js that every directory has	newfstatat 2,428, realpath 1	the same
fmt --staged src, shared	realpath 0, readlink 10	realpath 199, readlink 1,005
fmt --staged src, the staged name is unique	realpath 0	realpath 0
the 10 staged files as arguments	realpath 0	realpath 0
50 file arguments in 5 directories, 10 staged, shared	realpath 0	realpath 5
the tree named through a link above it, shared	realpath 2,001, readlink 16,016	realpath 201, readlink 1,616
the repro, from packages/a	realpath 2, newfstatat 304, nothing listed	realpath 2, newfstatat 305, the file is listed

• Allocations: no flag 17,820 and 17,820. lint --staged with nothing staged 18,140 and 18,139. With one staged file 18,306 and 18,308. With 201 staged files 18,519 and 18,522. The spread between runs is 4.
• Instructions for each walked file (release, 100,000 files, one thread, median of 5): no flag bun lint -3.0 and bun fmt -0.2, with a main-to-main spread of 2.9 and 0.5. lint --staged -70.5, fmt --staged -67.9, lint --changed=HEAD -70.6. The name test in has replaces a hash of the whole path.
• Git processes for each run: the same (2 with nothing staged, 3 with a staged file, 4 for --changed and for --staged --fix).
• Release binary (size): text +7,936 bytes (107,663,568 to 107,671,504), data +0, bss +0.
• No struct that a run holds for each file changes. git::Files, one for each run, gets names, resolves and real_directories and loses top. Loader gets two fields.

Each clause and the tests that need it. One debug build for each line, with that clause deleted, then test/cli/lint/git.test.ts.

Clause deleted	Tests that fail
the search reports a starting directory behind a symlink	6
the search reports a symlink it follows	8
the search reports that an argument named a file	5
bun fmt reports its arguments	4
bun lint hands the report to git::Files	2
a reported symlink makes as_listed resolve	10
an index entry is taken as it is	2
the texts under the paths through symlinks	4
the step up from a directory to the symlink above it	1
the check that a path through a symlink leads to the same directory	1
an index entry keeps its own text	1
the module graph gets the texts after the search	4
the second of two targets with one path is dropped	1
resolves is off after a search without symlinks	0, it saves the calls in the table above
a listed path is taken as it is	0, it saves one realpath for each listed file in a run through a symlink
has asks only for a listed name	0, it saves instructions, and a realpath for each directory in a run through a symlink

Without the order in --fix, the test with two configs is not stable: the staged text was one of two, 3 against 3 times in 6 runs.

Tests. test/cli/lint/git.test.ts: 88 pass. On main 14 of the 17 new tests fail. The other 3 pass on main and pin states that a simpler fix breaks. Also run on the debug build: lint.test.ts (712 pass), config-files.test.ts (842), format.test.ts (1,627), bunfig.test.ts (406), native-rules.test.ts (193), rule-throws.test.ts (51), doctor.test.ts (28), rules.test.ts (23), prettier-rule.test.ts (18). cargo check -p bun_lint_driver for x86_64-pc-windows-msvc, aarch64-apple-darwin and aarch64-unknown-linux-musl. The test file merges with #46479 and #46439 without a conflict (git merge-file).

Self-review: what is not done.

• A real-path fallback in Disk::read and in its directory listings. It is the complete fix for the import side. This PR covers the symlinks that the run went through. An import through any other symlink reads the file on disk, as on main: a workspace link in node_modules, a link to a file, a second link in a run that names only a file.
• Windows-only rows with a work tree at a drive root, or with the other letter case of the drive. No code in this change depends on how the root is spelled.
• A flat eslint.config.* row in the import test. It needs a stand-in plugin package. The row with a directory below the link as an argument takes the same path.

Windows. The new tests run on Windows. They did not run there before the first push, so this PR is a draft until those lanes pass. Git checks a link out as a symlink there only with core.symlinks=true. Other clones have a text file in its place and nothing to follow. If the working directory is not spelled as its final path (a subst drive, a short name), the file is still missed, as on main for a link above the work tree.

Left for later.

• A staged, then deleted file behind a link, by a search or by an argument. It is matched by git's path, as on main. A run at the root lints it.
• Exact resolution for a bun fmt directory argument, which would remove the realpath calls in the table.
• bun test --changed: test --changed: bind test files to the module graph by position, not by path #46583.

[robobun]

^{Updated 1:23 AM PT - Oct 25th, 2026}

✅ @robobun, your commit 7af9f7faf8f69f6174f35b3ba24c747dfcba0054 passed in Build #132461! 🎉

---

🧪   To try this PR locally:

bunx bun-pr 46857

That installs a local version of the PR into your bun-46857 executable, so you can run:

bun-46857 --bun

[robobun]

Status: draft. The new tests run on Windows for the first time in CI, so this stays a draft until those lanes pass.

Reproduction. On main, with the script in the Notes of the description: in packages/a, bun lint exits 1, and bun lint --changed=HEAD and bun lint --staged print No changed files to lint and No staged files to lint and exit 0. On this branch all three exit 1. test/cli/lint/git.test.ts has 17 new tests. On main 14 of them fail.

PR: #46857