nixos-install: clear executable cache after entering chroot

[xaverdh]

Clear the cache for executable locations after entering the chroot. The cached locations are no longer valid there.

This hopefully indeed resolves problems with nixos-install failing to find binaries from coreutils as witnessed in #241356 fixing it.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• 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/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 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
• Fits CONTRIBUTING.md.

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[xaverdh]

PS: if you try to reproduce that executable caching behavior of bash, you need to run it in non-interactive mode (i.e. bash -c '...'). In interactive mode, it will disable the executable cache.

[poliorcetics]

@xaverdh first time I'm testing such a PR, how can I declare my nixpkgs as pointing to yours ?

I'm using flakes if that helps.

[xaverdh]

@xaverdh first time I'm testing such a PR, how can I declare my nixpkgs as pointing to yours ?

I'm using flakes if that helps.

You can build the nixos-install script from this pr with

nix build github:NixOS/nixpkgs/refs/pull/355269/head#nixos-install

and then run ./result/bin/nixos-install

[poliorcetics]

Confirmed working on my use case, I don't get the "X not in PATH" error with this MR and I get it on regular nixpkgs

[xaverdh]

cc @Mic92

[poliorcetics]

Using

    overlays = [
      # <https://github.com/NixOS/nixpkgs/pull/355269>
      (final: super: {
        nixos-install = super.nixos-install.overrideAttrs (old: {
          patches = old.patches or [ ] ++ [ ../patches/nixos-install-no-coreutils-caching.patch ];
        });
      })
    ];

with the most recent nixpkgs-unstable did not work.

I took the patch from https://github.com/NixOS/nixpkgs/pull/355269.patch

I may have done something wrong, but I'm unsure what if so

[xaverdh]

Using

    overlays = [
      # <https://github.com/NixOS/nixpkgs/pull/355269>
      (final: super: {
        nixos-install = super.nixos-install.overrideAttrs (old: {
          patches = old.patches or [ ] ++ [ ../patches/nixos-install-no-coreutils-caching.patch ];
        });
      })
    ];

with the most recent nixpkgs-unstable did not work.

I took the patch from https://github.com/NixOS/nixpkgs/pull/355269.patch

I may have done something wrong, but I'm unsure what if so

can you see the patch getting applied (in the build output)?

[xaverdh]

ofborg failure appears unrelated?

[tom-kuca]

I run into the issue, the patch didn't fix it for me.

Command:

sudo ./result/bin/nixos-install --flake '.#voyager' --verbose --debug

Output:

+ nixos-enter --root /mnt -c '      set -e
      # Clear the cache for executable locations. They were invalidated by the chroot.
      hash -r
      # Create a bind mount for each of the mount points inside the target file
      # system. This preserves the validity of their absolute paths after changing
      # the root with `nixos-enter`.
      # Without this the bootloader installation may fail due to options that
      # contain paths referenced during evaluation, like initrd.secrets.
      # when not root, re-execute the script in an unshared namespace
      mount --rbind --mkdir / "$mountPoint"
      mount --make-rslave "$mountPoint"
      /run/current-system/bin/switch-to-configuration boot
      umount -R "$mountPoint" && (rmdir "$mountPoint" 2>/dev/null || true)'
perl: warning: Setting locale failed.
... perl complains ...
/nix/var/nix/profiles/system/sw/bin/bash: line 10: mount: command not found

I see the same error without the patch, only on line 8.

I'm on arch linux. I run into it when I tried to setup a new system using disko-install, later I tried nixos-install directly.

[Mic92]

The original bug fix was for coreutils. Not finding mount might be a different bug.

[xaverdh]

@ tom-kuca can you try adding

. /etc/profile

right after (or instead of) hash -r in that script?

[tom-kuca]

@xaverdh It works, the script finishes successfuly.

[xaverdh]

here you go: #365403