`nix build` is not able to find build.ninja!

Help
1

I have the following myapp.nix:

{ stdenv, pkgs, system }:
stdenv.mkDerivation rec {
  name = "myapp";
  src = ./.;

  enableShared = true;

  cmakePreset = {
    "x86_64-linux"   = "linux";
    "x86_64-darwin"  = "linux";
    "aarch64-darwin" = "osx";
  }."${system}";

  cmakeFlags = [
    "--preset ${cmakePreset}"
  ];
  cmakeBuildType = "Release";

  nativeBuildInputs = with pkgs; [ cmake git ninja ];

  buildInputs = (with pkgs; [
...
  ]);
}

My presets looks like this:

{
    "version": 9,
    "cmakeMinimumRequired": {
        "major": 3,
        "minor": 30,
        "patch": 0
    },
    "configurePresets": [
        {
            "name": "common-configure-settings",
            "description": "Options and CMake settings common to all configure presets",
            "binaryDir": "${sourceDir}/build/${presetName}",
            "hidden": true
        },
        {
            "name": "ninja",
            "hidden": true,
            "generator": "Ninja"
        },
        {
            "name": "linux",
            "hidden": false,
            "inherits": ["ninja"],
            "description": "Build preset for Linux",
            "environment": {
                "CXX_WARNINGS": "-Wall -Wextra -Werror -pedantic",
                "PLATFORM": "POSIX64"
            },
            "condition": {
                "type": "equals",
                "lhs": "${hostSystemName}",
                "rhs": "Linux"
            }
        }
    ]
}

I’m trying to create an action that builds this app using the following workflow:

name: build-linux

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

permissions:
  contents: read
  packages: read

jobs:
  build:
    runs-on: ubuntu-latest
    if: github.ref_name == 'main'
    steps:
    - uses: actions/checkout@v4
      with:
        token: ${{ secrets.GITHUB_TOKEN }}

    - uses: cachix/install-nix-action@v27
      with:
        extra_nix_config: |
          access-tokens = github.com=${{ secrets.GH_TOKEN }}

    - name: Build
      working-directory: ${{github.workspace}}
      run: nix build
      env:
        NIX_CONFIG: "access-tokens = github.com=${{ secrets.GH_TOKEN }}"

But it fails with the following message:

-- Build files have been written to: /build/gclqic95fzbdwfkdpff8w41gwgbvn4f1-source/build/linux
cmake: enabled parallel building
cmake: enabled parallel installing
Running phase: buildPhase
@nix { "action": "setPhase", "phase": "buildPhase" }
build flags: -j16
ninja: error: loading 'build.ninja': No such file or directory

How exactly is nix build working, and how do I tell it where to look for the build files?

2

So I think in essence what I need is a way to tell nix build that it can find the files it needs for the build phase at the above location.