nix-dotnet

A Nix module that builds reproducible .NET SDK derivations from global.json or explicit SDK versions.

Quick Start

1. Create global.json:

{
  "sdk": {
    "version": "10.0.100",
    "rollForward": "disable",
    "workloadVersion": "10.0.100.1"
  }
}

2. Use in your flake:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nix-dotnet.url = "github:adampoit/nix-dotnet";
  };

  outputs = { self, nixpkgs, nix-dotnet }:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};
    in {
      devShells.${system}.default = pkgs.mkShell {
        buildInputs = [
          (nix-dotnet.lib.${system}.mkDotnet {
            globalJsonPath = ./global.json;
            workloads = [ "android" "maui" ];
            outputHash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
          })
        ];
      };
    };
}

API Reference

mkDotnet

nix-dotnet.lib.${system}.mkDotnet {
  globalJsonPath = ./global.json;  # Use this for global.json-driven versioning
  # sdkVersion = "10.0.103";       # Alternative to globalJsonPath
  # workloadVersion = "10.0.100.1"; # Optional with sdkVersion
  additionalSdks = [
    {
      sdkVersion = "9.0.304";
    }
  ];
  outputHash = "sha256-...";       # Required for fixed-output
}

Parameters:

• globalJsonPath - Path to global.json (optional; mutually exclusive with sdkVersion)
• sdkVersion - SDK version string like 10.0.103 (optional; mutually exclusive with globalJsonPath)
• workloadVersion - Workload manifest version when using explicit sdkVersion (optional)
• workloads - List of workload names (optional, versions from global.json or workloadVersion)
• additionalSdks - Extra SDK configs to merge into the same dotnet installation (optional, no per-SDK hash)
• outputHash - Fixed-output derivation hash (required)

additionalSdks lets one dotnet command expose multiple SDK versions, so dotnet --list-sdks can show entries like .NET 10 and .NET 9 together.

Use one top-level outputHash for the whole combined installation.

Use checks.<system>.integration-tests to run all integration checks that are configured for that system.

Note: additionalSdks entries do not support installing workloads.

Getting the outputHash

1. Use a placeholder hash
2. Build: nix build (fails with "hash mismatch")
3. Copy the "got:" hash from the error
4. Update your flake with the correct hash

Note: Workload installation requires executing dotnet during build, so you cannot cross-compile workload-enabled SDKs (e.g., building Linux workloads on macOS).

Examples

• examples/basic/ - SDK without workloads
• examples/with-workloads/ - SDK with MAUI workloads
• examples/multi-sdk/ - single dotnet with both .NET 10 and .NET 9 SDKs

Supported Platforms

• x86_64-linux
• aarch64-linux
• x86_64-darwin
• aarch64-darwin

Development

# Unit tests (fast)
nix run github:nix-community/nix-unit -- --flake '.#tests'

# Integration tests (slow, builds SDK)
nix build .#checks.<system>.integration-tests --no-link

# All checks
nix flake check

# Build examples
nix build .#basic-example --no-link
nix build .#workload-example --no-link

License

MIT