Unable to mount external storage due to 'cannot be topologically sorted'

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1

Hi!
I run NixOS on a small SSD, and have a partition on my external HDD that I used to use for storing media (/dev/sda5). I added this in my /etc/nixos/configuration.nix:

fileSystems."/dev/sda5" = {
    device = "/dev/sda5";
    mountPoint = "/mnt/Storage";
  };

This was working for a few days uptil a few hours ago, when I was messing with flakes. I get these errors now:

Failed assertions:
       - The ‘fileSystems’ option can't be topologically sorted: mountpoint dependency path /mnt/Storage -> /mnt/Storage loops to /mnt/Storage
(use '--show-trace' to show detailed location information)

How can I prevent this?

2

Edit: solved my own problem.

(I was messing around with flakes and I had accidentally deleted my /etc/nixos/hardware-configuration.nix. In a panic, I ran nixos-generate-config again, which made a new hardware-configuration.nix containing the already mounted /mnt/Storage on my system. Thus when rebuilding my configuration some error may have occurred - I have no idea how this worked/came about.)

So, the solution is to edit /etc/nixos/hardware-configuration.nix and to remove the lines:

- fileSystems."/mnt/Storage" = {
- # some options here I don't remember (HARDWARE-CONFIGURATION.NIX!)
- };

Rebuilding the configuration now works.

3

I’m glad you figured it out.

You may want to consider keeping your configuration files in source control so that you can more easily restore accidentally deleted files :grimacing:

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