nix-shell: no longer parses a .drv file

[timbertson]

Issue description

I have a setup where my various workspace shells are added as GC roots, so they don't get cleaned up. This is a two-step process:

• build the .drv using nix-instantiate on shell.nix
• run nix-shell on the .drv

I can workaround this by running nix-shell on the shell.nix file instead, and presumably nothing will be different or rebuilt compared to the .drv, but this used to work so I'm reporting it as a regression:

Steps to reproduce

$ cat shell.nix
{ pkgs ? import <nixpkgs> {}}:
with pkgs;
stdenv.mkDerivation {
  name = "test-0.1";
  buildInputs = [ bash ];
}

$ nix-instantiate shell.nix --show-trace --quiet --indirect --add-root "$PWD/"shell.drv
/home/tim/dev/scratch/shell.drv

$ nix-shell shell.nix --run 'echo 1'
1

$ nix-shell shell.drv --run 'echo 1'
error: syntax error, unexpected ',', expecting ')', at /nix/store/m185dyc2dh7bdbz08hcqn3825hp7nsqy-test-0.1.drv:1:15

relevant .drv contents:

$ ls -l shell.drv
lrwxrwxrwx. 1 tim tim 56 Apr 22 12:18 shell.drv -> /nix/store/m185dyc2dh7bdbz08hcqn3825hp7nsqy-test-0.1.drv

$ cat shell.drv 
Derive([("out","/nix/store/bpysdn9xynmc51cd7faydd66r64dr7bq-test-0.1","","")],[("/nix/store/6bwh53x6086nwm5pv1c87jbj9jc5p06g-stdenv-linux.drv",["out"]),("/nix/store/qhvnja1jzfrir86h3w887nrw3fplxmn9-bash-4.4-p19.drv",["dev","out"])],["/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],"x86_64-linux","/nix/store/xn5gv3lpfy91yvfy9b0i7klfcxh9xskz-bash-4.4-p19/bin/bash",["-e","/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],[("buildInputs","/nix/store/fcvnn0gkdlg60z49rbp60dchvnrlg4fr-bash-4.4-p19-dev"),("builder","/nix/store/xn5gv3lpfy91yvfy9b0i7klfcxh9xskz-bash-4.4-p19/bin/bash"),("configureFlags",""),("depsBuildBuild",""),("depsBuildBuildPropagated",""),("depsBuildTarget",""),("depsBuildTargetPropagated",""),("depsHostBuild",""),("depsHostBuildPropagated",""),("depsTargetTarget",""),("depsTargetTargetPropagated",""),("name","test-0.1"),("nativeBuildInputs",""),("out","/nix/store/bpysdn9xynmc51cd7faydd66r64dr7bq-test-0.1"),("propagatedBuildInputs",""),("propagatedNativeBuildInputs",""),("stdenv","/nix/store/3y0wxpkxzs6yz73iw35d17qr1wp4p2i4-stdenv-linux"),("system","x86_64-linux")])

Technical details

$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 4.15.17-300.fc27.x86_64, Fedora, 27 (Workstation Edition)`
 - multi-user?: `no`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.0`
 - channels(tim): `"nixpkgs-18.09pre137305.d91caac6c3e"`
 - nixpkgs: `/home/tim/.nix-defexpr/channels/nixpkgs`

[glaebhoerl]

This looks like the same as NixOS/nix#1958 (which is not actually macOS-specific).

From that discussion, the actual issue is:

nix-shell interprets its argument as a derivation only when it is a store path

[stale]

Thank you for your contributions.

This has been automatically marked as stale because it has had no activity for 180 days.

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[gador]

I am having the same issue