Nix flakes problems with dev output

I am trying to migrate a project to nix. I am experimenting with nix flakes because I think It will be fit to my projects better.

Here is my example project.

It is a library, and I have a strange issue.
If i run:

nix build

al work fine

But if i want to open a dev console I get an error:

$ nix develop
error: --- Error ------------------------------------------------------------------------------------------------------------------------------------------------------------- nix
derivation '/nix/store/fik0j0bjbhs4xpx7va0nwvj9ljqw7kh0-base_lib-env.drv' has incorrect output '/nix/store/p42ysgq5ivif3qmjg01sfb588r5x2qal-base_lib-dev', should be '/nix/store/0nq30l4ngppv4zky2pgbvbaaxw6cyzsz-base_lib-env-dev'

I have this on my flake.nix

      outputs = [ "out" "dev"];

If i remove “dev” from ouputs, it works fine, but i dont have separated dev package.

I am using a debian with a nix multi user install. An using a nixpkgs-unstable updated today.

Thank you in advance

Thanks for the report. I’ve fixed this (nix develop: Support derivations with multiple outputs · NixOS/nix@68f524d · GitHub).