error:
       … while evaluating an expression to select 'drvPath' on it
         at «internal»:1:552:
       … while evaluating strict
         at «internal»:1:552:
       (stack trace truncated; use '--show-trace' to show the full trace)

       error: cannot coerce a set to a string: { derivations = «thunk»; names = «thunk»; }

       note: trace involved the following derivations:
       derivation 'Spacebar.Cdn-1.0.0-preview.20260421-191102-fetch-deps'
       derivation 'Spacebar.Cdn-1.0.0-preview.20260421-191102'

(for context: i added a custom namespaced attribute to the drv called __sbDmProjectReferences)

In reply to @daniel:nopemail.org
Anyone who has some experience with packaging a .NET-project using flakes? All prior art I’ve found seems to use the legacy way.

flakes are the same way as the "legacy way," all flakes help with is exposing the package.

what trouble are you running into?

In reply to @winterqt:nixos.dev

flakes are the same way as the "legacy way," all flakes help with is exposing the package.

what trouble are you running into?

In reply to @daniel:nopemail.org
I did that over and over, realized now that I of course called it with the wrong package name. Thanks though!

In reply to @winterqt:nixos.dev
(was it not erroring?)

Non-flake attempt: I am trying to make it work like this:

{ pkgs ? import <nixpkgs> {} }:
pkgs.mkShell {
  buildInputs = with pkgs; [ dotnet-sdk_7 dotnet-runtime_7 ];
  DOTNET_ROOT = with pkgs; lib.makeBinPath [ dotnet-runtime_7 ];
}

But still failing.

This seems to be enough to get the project up and running:

{ pkgs ? import <nixpkgs> {} }:
pkgs.mkShell {
  buildInputs = with pkgs.dotnetCorePackages; [ sdk_7_0 ];

  DOTNET_ROOT = with pkgs; "${dotnet-sdk_7}";
}

If anyone finds this helpful, this is how I've turned that into a flake.nix:

{
  description = "Basic .NET 7 flake";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem
      (system:
        let pkgs = nixpkgs.legacyPackages.${system}; in
        {
          devShells.default = 
            pkgs.mkShell {
              buildInputs = with pkgs.dotnetCorePackages; [ sdk_7_0 ];

              DOTNET_ROOT = with pkgs; "${dotnet-sdk_7}";
            };
        }
      );
}