nixos-rebuild: do not resolve flake path

[thiagokokada]

Motivation for this change

The removed lines converted the flake path passed by the command line from /some/path to git+file:///some/path.

This technically shouldn't cause any issues, however running nixos-rebuild switch inside a directory /nix/store will cause the switch to fail and leave a partially construct generation (see issue #144811 for details).

By itself this shouldn't be too much of an issue, however thanks to another issue in systemd-boot-builder.py this can leave the system in a broken state for those using boot.loader.systemd-boot (AFAIK the default), where future nixos-rebuild switch will fail (see issue #93694 for details).

The issue can be fixed by running nix-env -p /nix/var/nix/profiles/system --delete-generations old, however this makes newbies very confused and it is showing in our support threads in Matrix and Discourse (see https://discourse.nixos.org/t/need-help-on-failure-of-building-my-configuration/16842).

Keep in mind this is a workaround. The actual issue seems to be in nix itself (see: NixOS/nix#5510).

See also #150065 for an alternative fix that caused other issues.

Kudos for @figsoda for figuring out this fix.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.05 Release Notes (or backporting 21.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[thiagokokada]

Tested nixos-rebuild switch inside and outside /run/opengl-driver/lib, works fine.

[thiagokokada]

BTW, this should be backported to release-21.05 and release-21.11 since it also affects them. However to avoid the issue from #150065, in case this is merged I will wait sometime before backporting this to the respective branches.

[thiagokokada]

CC @edolstra and @cole-h since they're the folks that introduced the lines that are being deleted on this PR.

CC @colemickens @figsoda to help testing.

[thiagokokada]

Also CC @TredwellGit to test if this cause issues with ZFS.

[figsoda]

fixes the issue for me
would like it see another review since the other workaround caused issue on zfs

[thiagokokada]

fixes the issue for me would like it see another review since the other workaround caused issue on zfs

CC @TredwellGit.

[TredwellGit]

This works with the ZFS modules.

[thiagokokada]

Going to merge them and leave during some time on master branch to see if someone else detects some issues.

[github-actions]

Successfully created backport PR #153935 for release-21.11.

[Enzime]

Awesome work, I ran into this a couple of times but I was too lazy to debug it, glad to see it was fixed 🎉