My attempt to upgrade 20.03.2648.69af91469be (Markhor) to 20.9 failed due to libguestfs-1.40.2
# nix-channel --list
nixos https://nixos.org/channels/nixos-20.09
# nixos-rebuild test --upgrade
unpacking channels...
building Nix...
building the system configuration...
error: Package ‘libguestfs-1.40.2’ in /nix/store/rcq8cqxfypnr06fimibw19dvdypjhig5-nixos-20.09.1500.edb26126d98/nixos/pkgs/development/libraries/libguestfs/default.nix:88 is marked as broken, refusing to evaluate.
a) For `nixos-rebuild` you can set
{ nixpkgs.config.allowBroken = true; }
in configuration.nix to override this.
b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
{ allowBroken = true; }
to ~/.config/nixpkgs/config.nix.
(use '--show-trace' to show detailed location information)
Does anyone faced the issue?
Does anyone know how to fix it?
I had the same problem, and as a fairly new NixOS user had no idea how to fix it. Thanks to @palik for posting the question, and to @jonringer for fixing it so quickly!