`nix develop --command nix build` fails for some derivations in `nixos/nix` docker image

[CobaltCause]

I have the most minimal reproduction I could come up with here using nixos/nix:2.15.0.

Basically, the bug is that running nix develop --command nix build breaks, but only in the docker image. On my actual machine, this works fine. Additionally, running nix build without nix develop --command works fine both on my actual machine and in the container. This is all explained/demonstrated in the linked repository.

It's unknown to me whether this is reproducible with non-flakes equivalents, I didn't try.

I've also just noticed that changing packages.${system}.default to:

packages.${system}.default = derivation {
  inherit system;

  name = "wat";
  builder = "/bin/sh";

  args = ["-c" "echo wat > $out"];
};

does not reproduce the issue.

However, given that this behavior only arises depending on where (i.e. in or out of a docker container) nix is being invoked, I think this issue belongs here rather than nixpkgs.

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[SuperSandro2000]

the bug is that running nix develop --command nix build breaks

How? What breaks? Do you have logs?

[CobaltCause]

Yes, they're in the readme of the repo linked in the first sentence. I'll reproduce the logs for the incorrect behavior here:

error: builder for '/nix/store/iw1qf7h7jjxpkjf7759vv4pmr5hwswza-wat.drv' failed with exit code 1;
       last 2 log lines:
       > unpacking sources
       > variable $src or $srcs should point to the source
       For full logs, run 'nix log /nix/store/iw1qf7h7jjxpkjf7759vv4pmr5hwswza-wat.drv'.

I'll inline the flake.nix here while I'm at it I guess:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs?ref=nixos-unstable";
  };

  outputs = {
    self,
    nixpkgs,
  }:
  let
    system = "x86_64-linux";
    pkgs = nixpkgs.legacyPackages.${system};
  in
  {
    packages.${system}.default = pkgs.runCommandLocal "wat" {} ''
      touch $out
      echo wat > $out
    '';

    devShells.${system}.default = pkgs.mkShell {};
  };
}

[figsoda]

Something about the docker container seems to break how passAsFile handles $TMPDIR. The example works with this patch

--- a/flake.nix
+++ b/flake.nix
@@ -17,6 +17,8 @@
       echo wat > $out
     '';
 
-    devShells.${system}.default = pkgs.mkShell {};
+    devShells.${system}.default = pkgs.mkShell {
+      shellHook = "unset TMPDIR";
+    };
   };
 }

[CobaltCause]

Huh, yeah, I can confirm that makes it work in all cases. Very strange.

[pinage404]

I have the same issue : it works on my machine but fails in the CI or on my machine inside a container

https://gitlab.com/pinage404/nix-sandboxes/-/jobs/4634026045#L1000

even adding shellHook = "unset TMPDIR"; doesn't fix the problem

https://gitlab.com/pinage404/nix-sandboxes/-/jobs/4663181133#L1007

[pinage404]

Probably related

https://github.com/NixOS/nix/issues/6778

https://github.com/NixOS/nix/issues/7154

[CobaltCause]

Just dropping by to say this problem persists in 2.19.2 (hence the title change).

[maksar]

Issue is still in latest. Unsetting TMPDIR helps.

[gabyx]

Still an issue in nix 2.23.1. In an alpine image with installed nix.

[gabyx]

I get this error too: I do in an alpine container (root) after entering the devShell with nix develop I have exactly two tmp directories

• /tmp/nix-develop-17934-1835 : which seems from nix develop ??? It has permissions: drwxr-xr-x 1 root root.

• /tmp/nix-shell.1es4eb : Seems to be the tmp dir from the devShell.default in the flake.nix... It seems to have weird permissions: drwx------ 1 root root.

• TMPDIR is set to /tmp/nix-shell.1es4eb.

Then the following can be observed with nix build --rebuild:

• If I unset TMPDIR in the shell it works.

• If I set TMPDIR=/tmp it works.

• If I set TMPDIR=/nix-develop... (see above) , **the rebuild is non-deterministic.**because the derivations do not match. (which is weird)

• If I set TMPDIR=/nix-shell... (see above), the rebuild crashes with

  mktemp: failed to create file via template '/tmp/nix-shell.8h3Yn3/nix-build-rdf-protect.drv-0/tmp.XXXXXXXXXX':
  Permission denied
  

• If I set TMPDIR=/nix-shell... (see above) and correct the permissions to drwxr-x-r-x the build works but is non-deterministic.

• If I set TMPDIR=/tmp/gaga and mkdir -p gaga -> the build works but is non deterministic

This might look to me as a newbie the different TMPDIRs are used during build or something like that, which is weird... But might be wrong...