Add user channels to the default nix path

[grahamc]

Motivation for this change

See NixOS/nix#2033

I'll backport upon merge.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgsunstable

$ nix-channel --update
unpacking channels...
created 5 symlinks in user environment

$ nix-build '<nixpkgsunstable>' -A gitFull            
/nix/store/9i8vdd4757xnvyflf0fhszjw74cy74ib-git-2.16.2

$ nix run -f '<nixpkgsunstable>' gitFull  

[grahamc@Morbo:~]$ which git
/nix/store/9i8vdd4757xnvyflf0fhszjw74cy74ib-git-2.16.2/bin/git

[grahamc@Morbo:~]$ exit

$ nix-instantiate -E '(import <nixpkgsunstable> {}).gitFull'
warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/2iz7n7x4rldrn4dg9s5bg6a3qlxna7ms-git-2.16.2.drv

[grahamc]

@GrahamcOfBorg test openssh
@GrahamcOfBorg test login
@GrahamcOfBorg test env

[GrahamcOfBorg]

Failure on x86_64-linux (full log)

Attempted: tests.openssh

Partial log (click to expand)

cannot build derivation ‘/nix/store/3970kh8h84fcwjmcw0kvw69xj5dx6wfz-run-nixos-vm.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/v03dl9939xcg6sqfin8fb4kb2bsvsyk7-nixos-vm.drv’: 1 dependencies couldn't be built
building path(s) ‘/nix/store/18466xh1i341grvlisxif2959al1cw5i-closure-info’
/nix/store/aj9rz4k3xvg8q9fzqfnb0q123707zp0n-builder: line 1: .attrs.sh: No such file or directory
builder for ‘/nix/store/xcyxdcsjb6f54bypiv2i8231bms1c9d0-closure-info.drv’ failed with exit code 1
cannot build derivation ‘/nix/store/mvzidnd909ksxyr5z9jwa85m1ppmacpf-run-nixos-vm.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/qaaaivv8z1y7cn6cfrsi84p89dv900rm-nixos-vm.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/zsdf1xs9933pjj6pwy2bkx0md518dyzp-nixos-test-driver-openssh.drv’: 3 dependencies couldn't be built
cannot build derivation ‘/nix/store/c5shh79ayzw035ycimm658c50nsciwcm-vm-test-run-openssh.drv’: 1 dependencies couldn't be built
error: build of ‘/nix/store/c5shh79ayzw035ycimm658c50nsciwcm-vm-test-run-openssh.drv’ failed

[GrahamcOfBorg]

Success on x86_64-linux (full log)

Attempted: tests.login

Partial log (click to expand)

machine# [   24.283377] reboot: Restarting system
machine# [   24.283727] reboot: machine restart
vde_switch: EOF data port: Interrupted system call
collecting coverage data
syncing
6 out of 6 tests succeeded
test script finished in 26.36s
vde_switch: EOF on stdin, cleaning up and exiting
cleaning up
/nix/store/vnpn36ygig7xw3liw5b8xpamgn4jpij5-vm-test-run-login

[GrahamcOfBorg]

Failure on x86_64-linux (full log)

Attempted: tests.env

Partial log (click to expand)

building path(s) ‘/nix/store/924y1y6zavi47a5zgnp7c9hwrvj30c7g-etc’
building path(s) ‘/nix/store/h6nvqbzmx4rv5jwrjq10j6c8r071k3cg-nixos-system-machine-18.09.git.8bc041f’
building path(s) ‘/nix/store/ydxvkq2pwz8xqvnpm1l64g02vhy8yx7c-closure-info’
/nix/store/aj9rz4k3xvg8q9fzqfnb0q123707zp0n-builder: line 1: .attrs.sh: No such file or directory
builder for ‘/nix/store/8m7ldmmcp37xizsqzpf78basgwm109s4-closure-info.drv’ failed with exit code 1
cannot build derivation ‘/nix/store/gzv0rs1ygn1nbhnbvc5x0il0k6h150pq-run-nixos-vm.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/jsm2y9p2xv68jvcsyxg5mq279lpkq0w1-nixos-vm.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/hcgw2xv73a4rmdkyxir1gzd2waw5mdcc-nixos-test-driver-environment.drv’: 1 dependencies couldn't be built
cannot build derivation ‘/nix/store/532v3wbg7q7agn1p58cyjrnbapwapanx-vm-test-run-environment.drv’: 1 dependencies couldn't be built
error: build of ‘/nix/store/532v3wbg7q7agn1p58cyjrnbapwapanx-vm-test-run-environment.drv’ failed

[grahamc]

The two tests which failed seem due to the hosts not running 2.0. I'll look in to that. In the meantime, this patch works for me and the tests pass locally.

[vcunat]

I would probably switch the new line with the first line, because I think (1) per-user NIX_PATH elements should be given preference in comparison to (system-wide) root's elements, and (2) the root's elements should be "together".

[grahamc]

Agreed, updated.

[GrahamcOfBorg]

Failure on aarch64-linux (full log)

Attempted: tests.login

Partial log (click to expand)

building '/nix/store/5f6sg61k08mky7xfks58xxh7ny9haizx-user-units.drv'...
building '/nix/store/5ccyn39apv4hk38jw9grlwigzk5i0rwk-etc.drv'...
cannot build derivation '/nix/store/xlisrcfmvhlk44vwg37wszrn9z9kaby3-initrd.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/kahjcshbwr9m8w001l2vib64mjrmcn0y-nixos-system-machine-18.09.git.3ac6fb5.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/m6wkd7d9ikfwzjq99f587vdvln8fljgr-closure-info.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/mf036yplrxjhc20jss455wwrrbw5b2q8-run-nixos-vm.drv': 2 dependencies couldn't be built
cannot build derivation '/nix/store/ap4079ypmx01hiq4dn89wz4wrxgbna7j-nixos-vm.drv': 2 dependencies couldn't be built
cannot build derivation '/nix/store/q8xd52l1lbdb8955s159jjiajzdp51pj-nixos-test-driver-login.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/f7kj3ygsflqxc4q4h2mhxm36svzq4hcz-vm-test-run-login.drv': 1 dependencies couldn't be built
�[31;1merror:�[0m build of '/nix/store/f7kj3ygsflqxc4q4h2mhxm36svzq4hcz-vm-test-run-login.drv' failed

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: tests.env

Partial log (click to expand)

machine# [   16.950450] systemd[1]: Reached target Network.
machine# [   16.963572] systemd[1]: Starting DHCP Client...
machine# [   16.973408] systemd[1]: Starting Permit User Sessions...
machine: exit status 0
test script finished in 17.91s
cleaning up
killing machine (pid 627)
vde_switch: EOF on stdin, cleaning up and exiting
vde_switch: Could not remove ctl dir '/build/vde1.ctl': Directory not empty
/nix/store/bclyfl8m4ib9wqsg29rzwkrhldff8lvb-vm-test-run-environment

[GrahamcOfBorg]

Success on aarch64-linux (full log)

Attempted: tests.openssh

Partial log (click to expand)

server: exit status 0
2 out of 2 tests succeeded
test script finished in 33.84s
cleaning up
killing client (pid 627)
killing server_lazy (pid 639)
killing server (pid 651)
vde_switch: EOF on stdin, cleaning up and exiting
vde_switch: Could not remove ctl dir '/build/vde1.ctl': Directory not empty
/nix/store/l6k79aisr26a5m0img5mcw4ys9qy78pc-vm-test-run-openssh

[vcunat]

Yes, I think so, including cherry-pick to 18.03.

[shlevy]

🚢

[vcunat]

I'm slightly scared of being very hasty with such changes.

@edolstra: can you confirm this wasn't some intentional design decision? Apparently nix-env has ~/.nix-defexpr used for this purpose, but $NIX_PATH feels a much better way (more uniform), so going this way seems good. I hope we're not missing something.

[edolstra]

Well, this change doesn't make nix-env use NIX_PATH, so nothing really changes wrt nix-env.

[grahamc]

Update: Choosing not to backport this for now.

[lheckemann]

I like it. I agree it shouldn't be backported though — and this means it should go in the 18.09 release notes, not the 18.03 ones, right?