Lix fails to evaluate a specifically nested attribute set

player131007 commented

2025-06-02 07:56:29 +00:00

Steps To Reproduce

Try to evaluate this expression:

{
  foo.bar.baz = 1;
  foo = {
    bar.qux = 2;
  };
}

Nix (2.28.3) succeeds with no errors.
Lix fails with the message attribute 'bar' already defined.

Expected behavior

There should be no errors, like latest Nix.

`nix --version` output

nix (Lix, like Nix) 2.93.0
System type: x86_64-linux
Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux
Features: gc, signed-caches
System configuration file: /etc/nix/nix.conf
User configuration files: /home/player131007/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/player131007/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/player131007/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/player131007/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf
Store directory: /nix/store
State directory: /nix/var/nix
Data directory: /nix/store/7wv7x01fjp05n40yb263wlrm0hvhzbyn-lix-2.93.0/share

## Steps To Reproduce 1. Try to evaluate this expression: ```nix { foo.bar.baz = 1; foo = { bar.qux = 2; }; } ``` 2. Nix (2.28.3) succeeds with no errors. 3. Lix fails with the message `attribute 'bar' already defined`. ## Expected behavior There should be no errors, like latest Nix. ## `nix --version` output ``` nix (Lix, like Nix) 2.93.0 System type: x86_64-linux Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /home/player131007/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/player131007/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/player131007/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/player131007/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/7wv7x01fjp05n40yb263wlrm0hvhzbyn-lix-2.93.0/share ```

player131007 added the

bug

label

2025-06-02 07:56:29 +00:00

piegames commented

2025-06-02 10:03:44 +00:00

Member

I can reproduce with Lix 2.91.1. Moreover, the order of the attributes is important. If you swap the declarations, it doesn't fail

piegames added the

Area/evaluator

regression

labels

2025-06-02 10:04:33 +00:00

piegames commented

2025-06-02 14:28:22 +00:00

Member

Would be nice to have someone bisect this. Given that it was in a pretty early release, I suspect it might stem from the parser rewrite itself

pennae commented

2025-06-02 14:30:53 +00:00

Owner

this was present in 2.18 already, it's not a lix regression

piegames removed the

regression

label

2025-06-02 14:31:54 +00:00

piegames commented

2025-06-02 14:32:36 +00:00

Member

So Nix used to forbid this and then it got allowed in a later release after forking?

pennae commented

2025-06-02 14:35:51 +00:00

Owner

that seems to be the case. further tests show it failing all the way back to 2.3, so the bug is quite old

srd424 commented

2025-06-25 19:40:09 +00:00

Just hit this switching from cppnix to lix, I think their bug is https://github.com/NixOS/nix/issues/11268, in which case the fix was in https://github.com/NixOS/nix/pull/11294 (landing in 2.26.)

👍 1

raito self-assigned this

2025-06-27 10:50:14 +00:00

piegames commented

2025-06-27 12:44:44 +00:00

Member

@raito I see you just self assigned, but I can also take this over within a couple of months. This issue is literally over half a decade old so a couple of months shouldn't matter too much, and more importantly, I'm currently cleaning up the test suite as part of the functional2 migration so would prefer to have functional/lang tests frozen until then

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Lix fails to evaluate a specifically nested attribute set #845

Steps To Reproduce

Expected behavior

nix --version output

`nix --version` output