macOS release binary appears to require Homebrew libusb at runtime after 1.16.0

[TyceHerrman]

I’m seeing what looks like a macOS runtime-linking issue with the released fnox binary.

I installed fnox via mise, and the binary fails to start because dyld cannot find:

/opt/homebrew/opt/libusb/lib/libusb-1.0.0.dylib

otool -L on the installed binary shows that exact dylib path as a runtime dependency.

Possible explanation:

v1.16.0 added ctap-hid-fido2 and yubico_manager to fnox’s main dependencies. Those are hardware-token crates,: ctap-hid-fido2 documents a libusb-1.0 dependency on some platforms, and the YubiKey challenge-response crate lineage derived from yubico_manager documents that the default rusb backend depends on libusb, while nusb exists specifically to avoid libusb. Since rusb is a wrapper around native libusb, a macOS release binary in the 1.16.x line ending up linked to libusb would be consistent with the new FIDO2/YubiKey support added in that release series, even if that still does not by itself prove the exact packaging/linking path for the published binary.

Questions:

1. Is the macOS release artifact expected to depend on Homebrew libusb at runtime?
2. If yes, should that be documented as a runtime prerequisite for macOS users?
3. If no, should the macOS build be adjusted so the release binary does not hardcode a Homebrew-specific libusb path?

I can provide the exact dyld error and otool -L output if helpful.

Written with help from Codex

[jdx]

Opened a draft approach in #348 — it replaces yubico_manager (which hard-links libusb via rusb → libusb1-sys) with a minimal reimplementation that loads libusb-1.0 at runtime via libloading (dlopen). The binary starts and runs normally without libusb; the YubiKey provider returns a clear error with install instructions only when it's actually used.

Not sure yet if this is the right direction — wanted to get it up for discussion. The FIDO2 provider was already fine (hidapi uses IOKit natively on macOS, no libusb).

This comment was generated by Claude Code.