bug: v1.4.1 has weird `devenv:enterShell failed with error: No such file or directory (os error 2)` error

[gabyx]

Describe the bug

I have changed to use /latest in the devenv input:

    # The devenv module to create good development shells.
    devenv = {
      url = "github:cachix/devenv/latest";
      inputs.nixpkgs.follows = "nixpkgs";
    };

In my flake.nix, which updated to v1.4.1:I suddenly have this strange issue:

nix develop --no-pure-eval --accept-flake-config "/persist/repos/repository-template/./tools/nix#default" --command zsh
warning: Git tree '/persist/repos/repository-template' is dirty
Running tasks     devenv:enterShell
Failed            devenv:enterShell 0ms
1 Failed                            371.87µs

--- devenv:enterShell failed with error: No such file or directory (os error 2)
--- devenv:enterShell stdout:
--- devenv:enterShell stderr:
---

To reproduce
See the MWE here:

• Before flake.nix: https://gist.github.com/gabyx/eccf4f46ff9e83450c1c48aa4747a1b8#file-flake-nix-before

• Before flake.lock: https://gist.github.com/gabyx/eccf4f46ff9e83450c1c48aa4747a1b8#file-flake-lock-before

• Bug flake.nix: https://gist.github.com/gabyx/eccf4f46ff9e83450c1c48aa4747a1b8#file-flake-nix-bug

• Bug flake.lock: https://gist.github.com/gabyx/eccf4f46ff9e83450c1c48aa4747a1b8#file-flake-lock-bug

Version

v1.4.1 (/latest) in flake.nix with bug.

[gabyx]

Its due to not using nixpkgs = "github:cachix/devenv-nixpkgs/rolling" for everything which is really strange. But even with

pure eval and

inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; # THIS DOES STRANGELY NOT WORK??
    nixpkgsdevenv.url = "github:cachix/devenv-nixpkgs/rolling";

    # The devenv module to create good development shells.
    devenv = {
      url = "github:cachix/devenv/latest";
      inputs.nixpkgs.follows = "nixpkgsdevenv";
    };
    devenv-root = {
      url = "file+file:///dev/null";
      flake = false;
    };
  };
...

It seems not to work.
Please check the MWE Repo: https://github.com/gabyx/devenv-bug-report/commits/main
With the first commit working, the second doesnt. Why does that happen??

[gabyx]

It works when the pkgs input in mkShell is locked to the nixpkgsDevenv (rolling) input:

inputs.devenv.lib.mkShell {
  inherit inputs;
  pkgs = inputs.nixpkgsdevenv.legacyPackages.${pkgs.system};
...

Should that be mentioned in the docs?
Since you will run probably in to the same issue when updating the rolling input, do you know what the issue is?

[domenkozar]

It could be the something has changed on nixpkgs master, that's why we recommend to pin nixpkgs.

[gabyx]

@domenkozar Ok, maybe I am gonna highlight this more in the flake readme: its correct that one only should pin the pkgs input of the mkShell function.
If the module functions then uses this pinned one or nixpks-unstable does not really matter, right?

[jozuas]

I find that setting nixpkgs.url in devenv.yaml to a recent commit causes the same problem

# yaml-language-server: $schema=https://devenv.sh/devenv.schema.json
inputs:
  nixpkgs:
    url: github:nixos/nixpkgs/2bfc080 

• Building shell ...
• Using Cachix: devenv
✔ Building shell in 117ms
Running tasks     devenv:enterShell
Failed            devenv:enterShell 0ms
1 Failed                            516.04µs

--- devenv:enterShell failed with error: No such file or directory (os error 2)
--- devenv:enterShell stdout:
--- devenv:enterShell stderr:
---

[domenkozar]

I use thest latest nixpkgs in a few places and haven't spotted this. Is it macos specific?

[jozuas]

I use thest latest nixpkgs in a few places and haven't spotted this. Is it macos specific?

I am on MacOS with devenv 1.4.0

Right now trying to find an older commit to pin to, to see when this problem started occuring

[jozuas]

@domenkozar

Well that was a pain, but this is what I discovered by bisecting https://hydra.nixos.org/jobset/nixpkgs/trunk/evals?page=8 builds.

• Commit d865758 from 2025-02-20 and onwards causes the No such file or directory
• Commit dad5644 from 2025-02-20 and before does not cause the error

The diff is crazy huge though NixOS/nixpkgs@dad5644...d865758

[domenkozar]

Nothing comes to my kind, it's either mkdir or chmod failing, I've pushed 45ae910 to clarify if it's the latter. Can you try with that? If it's not mkdir, then I wonder what's your value of $DEVENV_DOTFILE?

[jozuas]

I looked at the change you pushed, and now I'm properly confused, as to why different nixpkgs would affect this.

Nonetheless:

~/dev/terrapin-app > direnv reload
• Building shell ...
• Using Cachix: devenv
✔ Building shell in 127ms
Running tasks     devenv:enterShell
Failed            devenv:enterShell 0ms
1 Failed                            790.92µs

--- devenv:enterShell failed with error: No such file or directory (os error 2)
--- devenv:enterShell stdout:
--- devenv:enterShell stderr:
---

~/dev/terrapin-app > echo $DEVENV_DOTFILE
/Users/juozas/dev/terrapin-app/.devenv
~/dev/terrapin-app > ls $DEVENV_DOTFILE
devenv.json  flake.json  gc  imports.txt  input-paths.txt  load-exports  nix-eval-cache.db  nix-eval-cache.db-shm  nix-eval-cache.db-wal  processes  profile  run  state
~/dev/terrapin-app > chmod +x "$DEVENV_DOTFILE/load-exports"
~/dev/terrapin-app > echo $?
0
~/dev/terrapin-app > mkdir -p $DEVENV_DOTFILE
~/dev/terrapin-app > echo $?
0

devenv shell and direnv reload both cause the same enterShell failure

[jozuas]

The nixpkgs commit d865758 (that was previously failing) with devenv update and devenv version 1.4.1 (as opposed to 1.4.0) is no longer failing on direnv reload. Newer commits than d865758 are now also resulting in no failures to enter shell.

Just updating devenv to version 1.4.1 did not have the same effect.

[domenkozar]

You need to run bisecting with --refresh-eval-cache, although bisecting should trigger that.

[domenkozar]

Is this still happening?

[jozuas]

The nixpkgs commit d865758 (that was previously failing) with devenv update and devenv version 1.4.1 (as opposed to 1.4.0) is no longer failing on direnv reload. Newer commits than d865758 are now also resulting in no failures to enter shell.

Just updating devenv to version 1.4.1 did not have the same effect.

Since upgrading devenv to version 1.4.1 and running devenv update, the problem disappeared and never appeared again