Init nix flakes

[haruki7049]

• How about pinning nixpkgs using nix-flakes instead of ./pinned-nixpkgs.nix? #207
• nix-profile support #169

This PR creates /flake.nix and /flake.lock files.

Changes

• Create /flake.nix and /flake.lock
  • This PR allow this following commands to be run:

nix build .#simula
nix build

• nix profile command support
  • Then you can run nix profile install github:haruki7049/Simula/init-flakes -L
• Delete /pinned-nixpkgs.nix
• Delete externalSrc attribute and localSrc declaration. Use override function to override src attribute.
• Delete unused submodule, godot_headers
• Update wlroots and godot submodule
• Initialize nix-direnv to use .#devShells.default
• Initialize /.envrc to use nix-direnv
• Add nix-checker CI to check Nix derivation
• Add /addons/godot-haskell-plugin/justfile
  • Available recipes
    • build
    • default
    • profile-build
    • watch-build

My environment

$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.6.62, NixOS, 25.05 (Warbler), 25.05beta710087.23e89b7da85c`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.24.10`
 - channels(root): `"nixos"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[haruki7049]

I made a mistake. For now this PR should be draft

[haruki7049]

Commit hash: 3c58c0c

I build Simula with below diff and nix-build -E 'with import <nixpkgs> { }; callPackage ./. { onNixOS = true; devBuild = true; }', then this build successed.

diff --git a/.gitmodules b/.gitmodules
index 2cb9882..271bbcd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,8 +4,8 @@
        shallow = true
 [submodule "submodules/wlroots"]
        path = submodules/wlroots
-       url = https://github.com/SimulaVR/wlroots
-       branch = simula
+       url = https://github.com/haruki7049/wlroots-simula
+       branch = edit-nix-files
        shallow = true
 [submodule "submodules/godot"]
        path = submodules/godot
@@ -41,4 +41,4 @@
 [submodule "submodules/monado"]
        path = submodules/monado
        url = https://github.com/SimulaVR/monado-xv.git
-       branch = xr50
\ No newline at end of file
+       branch = xr50
diff --git a/Simula.nix b/Simula.nix
index 5166a0f..b62b1c0 100644
--- a/Simula.nix
+++ b/Simula.nix
@@ -23,7 +23,7 @@ let
     wayland-protocols-dev = wayland-protocols.overrideAttrs (oldAttrs: {
       stdenv = stdenvRes;
     });
-    wlroots-dev = callPackage ./submodules/wlroots/wlroots.nix { stdenv = stdenvRes; };
+    wlroots-dev = callPackage ./submodules/wlroots { stdenv = stdenvRes; };
     vulkan-loader-custom = if onNixOS then vulkan-loader else (callPackage ./nix/vulkan-loader.nix { });
     glibc-locales = glibcLocales;
     godot = callPackage ./submodules/godot/godot.nix { devBuild = devBuild; onNixOS = onNixOS; };
diff --git a/submodules/wlroots b/submodules/wlroots
index 017c7ca..7a3d488 160000
--- a/submodules/wlroots
+++ b/submodules/wlroots
@@ -1 +1 @@
-Subproject commit 017c7ca435e2198fab6fde16db918b64aa0d6232
+Subproject commit 7a3d48833ad58a19fed81f87744a0e69f505f3f5

[haruki7049]

Commit hash: 3c58c0c

I build Simula with below diff and nix-build -E 'with import <nixpkgs> { }; callPackage ./. { onNixOS = true; devBuild = true; }', then this build successed.

This means that SimulaVR can be built with Nix flakes if SimulaVR/wlroots#1 merged into SimulaVR/wlroots

[haruki7049]

Commit hash: b539685

I am so sad, because I understand that we cannot use Git submodules in checks attrset... We can still use Git submodules by nix build command, by:

nix build .?submodules=1#devBuild-onNixOS

[haruki7049]

I can do these things but I cannot judge whether I should do in this PR or not:

• As /.github/workflows/nix-checker, Create an Action to check whether Simula can be built with nix build command.
• In the flakes, Create devShells.${system}.default for developing

---

I also can do these things but I don't think that I should do in this PR:

• Move /Simula.nix to /default.nix in order to build with nix-build -E 'with import <nixpkgs> { }; callPackage ./. { }
• Refactoring the Derivation in /Simula.nix, such as organize buildInputs and installPhase attributes

[haruki7049]

TODO:

• Delete Shell scripts
• Delete devBuild
• Delete onNixOS
• Initialize /.github/workflows/nix-checker.yml
• Refactoring Simula.nix and default.nix

[haruki7049]

I'll do some more work...