Rebuild takes a long time (4 min) due to a single file evaluation

Help
1

I’m using NixOS with Nixpkgs 24.11 and HM 24.05 as a NixOS module.

I started noticing that running a nixos-rebuild switch took a very long time after installing HM. I ran the same command with --verbose and I noticed that while the entire rebuild takes 4 minutes (not changing anything from the configuration), the verbose shows that I get stuck at:

evaluating file '/nix/store/nxfmhwq2kaj5rzxss9xnzc5ab5n7ljx3-nixos-24.11/nixos/pkgs/development/python-modules/u-msgpack-python/default.nix'

during 3 min and 45 seconds. This is also not the last “evaluating file” message. What should I do? Is this issue known?

2

Please make sure you upgrade home-manager to 24.11 as well. The combination you describe is unsupported.

There should be no reason to rebuild python311Packages.u-msgpack-python, since on nixos-24.11 it is generally cached.

It’s build took me only a few second on my 12th gen Intel laptop, not sure why it would take multiple minutes for you.

3

Thanks for the input. After changing the home-manager tarball target to 24.11, I rebuilt and the same thing happened (stuck for a long time on u-msgpack-python/default.nix).

Then, I rebooted and tried rebuilding again. Sadly, the issue is not solved by upgrading HM. I can also confirm that the issue cannot be caused to my CPU (11th Intel i7), RAM nor any hardware related causes.