Nixos-rebuild: the reference 'refs/heads/main' cannot be peeled

What does this error mean? and how do i fix it? I got this when trying to update my flake: [spiderunderurbed@daspidercave:/etc/nixos]$ sudo nix flake update [sudo] password for spiderunderurbed: error: … while fetching the input 'git+file:///etc/nixos' error: getting working directory status: the reference 'refs/heads/main' cannot be peeled - Cannot retrieve reference target (libgit2 error code = 3) [ble: exit 1] Directory contents: [spiderunderurbed@daspidercave:/etc/nix...