Files
bun.sh/test/cli
mmitchellg5 85080f7949 fix: handle DT_UNKNOWN in dir_iterator for bind-mounted filesystems (#25838)
### What does this PR do?
Fixes #24007
Possibly fixes https://github.com/oven-sh/bun/issues/18902,
https://github.com/oven-sh/bun/issues/7412

Some filesystems (bind mounts, FUSE, NFS) don't provide `d_type` in
directory entries, returning `DT_UNKNOWN`. This caused glob and
recursive readdir to skip entries entirely.

## Problem
On Linux filesystems that don't populate `d_type` in directory entries
(bind mounts, FUSE, NFS, some ext4 configurations), `readdir()` returns
`DT_UNKNOWN` instead of the actual file type. This caused:
- `Bun.Glob` to skip files/directories entirely
- `fs.readdirSync(..., {recursive: true})` to not recurse into
subdirectories
- `fs.readdirSync(..., {withFileTypes: true})` to report incorrect types

## Solution
Implemented a **lazy `lstatat()` fallback** when `d_type == DT_UNKNOWN`:

- **`sys.zig`**: Added `lstatat()` function - same as `fstatat()` but
with `AT_SYMLINK_NOFOLLOW` flag to correctly identify symlinks
- **`GlobWalker.zig`**: When encountering `.unknown` entries, first
check if filename matches pattern, then call `lstatat()` only if needed
- **`node_fs.zig`**: Handle `.unknown` in both async and sync recursive
readdir paths; propagate resolved kind to Dirent objects
- **`dir_iterator.zig`**: Return `.unknown` for `DT_UNKNOWN` entries,
letting callers handle lazy stat

**Why `lstatat` instead of `fstatat`?** We use `AT_SYMLINK_NOFOLLOW` to
preserve consistent behavior with normal filesystems - symlinks should
be reported as symlinks, not as their target type. This matches [Node.js
behavior](https://github.com/nodejs/node/blob/main/lib/internal/fs/utils.js#L251-L269)
which uses `lstat()` for the DT_UNKNOWN fallback, and follows the lazy
stat pattern established in PR #18172.

### How did you verify your code works?

**Testing:**
- Regression test: `test/regression/issue/24007.test.ts`
- FUSE filesystem test: `test/cli/run/glob-on-fuse.test.ts` (reuses
`fuse-fs.py` from PR #18172, includes symlink verification)
- All existing glob/readdir tests pass
- **Verified in Docker bind-mount environment:**
  - Official Bun: `0 files`
  - Patched Bun: `3 files`

**Performance:** No impact on normal filesystems - the `.unknown` branch
is only hit when `d_type == DT_UNKNOWN`. The lazy stat pattern avoids
unnecessary syscalls by checking pattern match first.

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
2026-01-22 13:44:49 -08:00
..