Warning: unhandled Platform key FamilyDisplayName on macOS

[mabroor]

Description

When entering devbox shell on macOS, the following warning is displayed:

warning: unhandled Platform key FamilyDisplayName

This is a cosmetic warning that doesn't affect functionality, but it can be confusing for users and clutters terminal output.

Steps to Reproduce

1. On macOS (tested on newer versions with recent Xcode)
2. Run devbox shell in any devbox project
3. Observe the warning message

Environment

• macOS (newer versions with updated Xcode)
• Devbox (various versions)

Root Cause Analysis

The warning originates from xcbuild's xcrun in Nix when it parses modern Xcode Platform plist files. On newer macOS versions, Apple added a FamilyDisplayName key to Platform plists that the Nix-provided xcrun doesn't recognize.

When entering devbox shell, the PATH is modified to include Nix's xcrun (from xcbuild) instead of Apple's /usr/bin/xcrun. The Nix version hasn't been updated to handle newer Xcode plist keys, causing this warning.

Related Issues

• xcbuild.xcrun: issues in fallback handling NixOS/nixpkgs#376958 - Upstream nixpkgs issue tracking this xcbuild problem
• macOS nix-shell: Tide prompt spams “unhandled Platform key FamilyDisplayName” when PATH resolves to xcbuild xcrun IlanCosman/tide#611 - Documents the same warning in nix-shell environments
• git broken inside all devbox projects with a 'xcrun: error: missing DEVELOPER_DIR path' #2566 - Related xcrun issues in devbox on macOS

Workarounds

1. Ignore it - The warning is cosmetic and doesn't affect functionality
2. Wait for upstream fix - Once nixpkgs updates xcbuild to handle newer Xcode plist keys, this should resolve

Suggested Resolution

This will likely be resolved once the upstream nixpkgs issue is fixed. Devbox could potentially:

1. Suppress this specific warning from stderr
2. Document this as a known issue for macOS users
3. Track the upstream fix and update the nixpkgs pin when available

[icorbett]

This isn't purely cosmetic in the case where someone is using the Apple developer tools version of git, or other relevant commands, rather than ones provided by Nix or Devbox.

% git pull
xcrun: error: missing DEVELOPER_DIR path: /nix/store/rhlyld20zdzdi5wghb4b12gw52s9whr9-apple-sdk-11.3

% echo $?
1

The workaround of adding unset DEVELOPER_DIR to the devbox.json init_hook is working for me:

    "shell": {
      "init_hook": [
        "echo 'Welcome to devbox!' > /dev/null",
        "unset DEVELOPER_DIR"