workaround.sh

if ! nix-shell -p hello --run 'hello' &>/dev/null; then
	# The following condition addresses https://github.com/NixOS/nix/issues/2523
	if [[ "$(uname -s)" == "Darwin" ]] && [[ "$( grep -E 'nix-daemon.*fork()' /var/log/system.log | wc -l )" -gt 0 ]]; then
		>&2 echo ">>> I ran into a Mac-specific bug (https://github.com/NixOS/nix/issues/2523) and I'm applying the workaround automatically for it."
		sudo launchctl remove org.nixos.nix-daemon
		sed \
			-e "s:<key>Program</key>:<key>EnvironmentVariables</key><dict><key>OBJC_DISABLE_INITIALIZE_FORK_SAFETY</key><string>YES</string></dict>&:g" \
			/Library/LaunchDaemons/org.nixos.nix-daemon.plist > /tmp/org.nixos.nix-daemon.plist
		sudo mv /tmp/org.nixos.nix-daemon.plist /Library/LaunchDaemons/org.nixos.nix-daemon.plist
		sudo chown root: /Library/LaunchDaemons/org.nixos.nix-daemon.plist
		sudo launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist
		nix-shell -p hello --run 'hello'
	fi
fi