Support fuse-t on macOS (NFS-backed mounts + sshfs 2.9 option names)

[dpezto]

Summary

fuse-t is the actively-maintained, kextless
replacement for macFUSE (no kernel extension, works on Apple Silicon without reduced-security
boot). sshfs.nvim advertises macOS support but has no fuse-t handling, and two independent
defaults make it unusable under fuse-t out of the box.

Environment

• sshfs.nvim v2.0.0-42-g57f5862
• macOS; fuse-t cask 1.2.7 + fuse-t-sshfs cask 1.0.2 (from the
  macos-fuse-t/homebrew-cask tap; upstream macos-fuse-t/sshfs,
  a fuse-t-specific fork reporting SSHFS 2.9 / libfuse 2.9.9 via sshfs --version)
• No macFUSE kext, and no generic Homebrew sshfs formula installed

Bug 1 — mount detection misses fuse-t (breaks keymaps + auto-unmount)

fuse-t presents an SSHFS mount as an NFS mount:

fuse-t:/sshfs_nvim_mount on /Users/me/mnt/host (nfs, nodev, nosuid, mounted by me)

get_system_mounts() (lua/sshfs/lib/mount_point.lua:35-43) only matches fuse.sshfs,
(macfuse, (osxfuse, and the scan loop only proceeds on lines matching sshfs/macfuse.
The fuse-t line matches none → list_active() returns [] even with a live mount.

What happens:

• Every mount-dependent keymap fails with the notify No active SSH connections.
• cleanup_unused_mounts() on VimLeave (init.lua:55 → session.lua:156) iterates
  list_active(), so the mount is never unmounted on exit → orphaned fuse-t mount +
  stale mountpoint.

Expected: fuse-t mounts are detected like macFUSE / fuse.sshfs — keymaps see the active
mount and it is unmounted on exit.

Bug 2 — default cache options hang under sshfs 2.9

config.lua:18-20 defaults:

dir_cache       = "yes",
dcache_timeout  = 300,
dcache_max_size = 10000,

build_sshfs_args (lib/sshfs.lua:9-24) turns these into dir_cache=yes, dcache_timeout=300,
dcache_max_size=10000, passed as a single comma-joined -o (lib/sshfs.lua:64:
{ "sshfs", remote, mount, "-o", table.concat(options, ",") }).

What happens: dir_cache / dcache_* are sshfs-3.x option names (the directory-cache
rework in sshfs 3). Generic sshfs on Linux/macFUSE is 3.x and has them — but fuse-t-sshfs
is the sshfs 2.9 fork, whose sshfs --help lists only cache=BOOL, cache_timeout=N,
cache_max_size=N (no dir_cache/dcache_*). So the stock config feeds this binary option
names it doesn't define; because they share one -o, a single unknown token poisons the whole
list. Observed: the mount never completes — :SSHFSMount / <leader>mm "does nothing", no
error surfaced. Reproduces with stock config, no overrides.

Expected: stock config mounts under fuse-t-sshfs (sshfs 2.9) — the plugin emits
2.9-compatible cache=/cache_timeout= when an sshfs < 3 is detected, or documents that
fuse-t users must override these.

Secondary — unmount timing

Even with Bug 1 fixed, MountPoint.unmount (mount_point.lua:212-232) runs
jobstart+jobwait(…,5000) from a VimLeave callback; async jobs during editor teardown
are unreliable for fuse-t's NFS backend. A synchronous unmount from VimLeavePre, escalating
to diskutil unmount force, is reliable in practice.

Reproduction

1. macOS with fuse-t + fuse-t-sshfs (brew install --cask fuse-t macos-fuse-t/homebrew-cask/fuse-t-sshfs) — i.e. the sshfs 2.9 fuse-t fork, no macFUSE.
2. Stock sshfs.nvim config.
3. :SSHFSMount a host → mount never completes (Bug 2). Set sshfs_options.dir_cache / dcache_timeout / dcache_max_size = false to get past it.
4. Mount succeeds; mount shows the fuse-t:/… (nfs) line, but any mount keymap reports "No active SSH connections" (Bug 1).
5. Quit nvim → mount stays (Bug 1 cascade).

Suggested fixes

• Detection: match fuse-t NFS mounts (fuse-t: source / (nfs type). More robust:
  track plugin-created mounts in internal state (you already ship lib/lockfile.lua) instead
  of scraping the system mount table, which sidesteps the format problem entirely. Note: the
  fuse-t NFS line shows fuse-t:/<volname>, not user@host:/path, so host/remote-path can't
  be recovered by parsing alone — internal tracking is the clean path.
• Cache options: gate dir_cache/dcache_* behind an sshfs-major-version check, or emit
  2.9-compatible cache=/cache_timeout= when sshfs < 3 is detected. At minimum, document
  that fuse-t users must disable them.
• Unmount: prefer VimLeavePre + synchronous unmount; once Bug 1 is fixed the cascade
  resolves.

Working reference

A complete local compat shim (detection monkey-patch, 2.9-safe option set, synchronous
VimLeavePre unmount):
sshfs-nvim.lua.

[uhs-robert]

Thank you for the bug report and the deep analysis. This has been a busy work for me but I will put this on my radar to get done in the next couple of weeks!