Could not CreateWindow(): IWindowingPlatform is not registered

[stefanwatt]

I compiled from source and I get this error when trying to launch fvim:

Unhandled exception. System.Exception: Could not CreateWindow(): IWindowingPlatform is not registered.
   at Avalonia.Controls.Platform.PlatformManager.CreateWindow()
   at Avalonia.Controls.Window..ctor()
   at FVim.CrashReport..ctor()
   at FVim.Program.startCrashReportWindow(FSharpFunc`2 app, Exception ex)
   at FVim.Program.Main(String[] args)
[1]    56833 IOT instruction (core dumped)  /home/stefan/Projects/fvim/bin/Release/net6.0/linux-x64/publish/FVim

My System:

$ dotnet --list-runtimes                                                                                                                                      [23:47:42]
Microsoft.AspNetCore.App 6.0.25 [/nix/store/k1ld6p66rdvzlcqhrnmhgllycr745490-dotnet-sdk-6.0.417/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.25 [/nix/store/k1ld6p66rdvzlcqhrnmhgllycr745490-dotnet-sdk-6.0.417/shared/Microsoft.NETCore.App]

stefan@nixos: ~
$ dotnet --version                                                                                                                                            [23:51:31]
6.0.417

Am I missing dependencies? ChatGPT suggested libX11 might be an issue, but it's installed on my system, too. Maybe it can't fight it under the usual path cause I'm using nixos?

[nbfritch]

I also ran into this issue on NixOS.
I found the libraries that were failing to be loaded by using strace dotnet bin/Release/net6.0/FVim.dll.
Here is the flake containing the devShell I was able to get FVim to run with:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };
  outputs = { self, nixpkgs }:
    let pkgs = nixpkgs.legacyPackages.x86_64-linux.pkgs;
    in
    {
      devShells.x86_64-linux.default = pkgs.mkShell rec {
        buildInputs = with pkgs; [
          bashInteractive
          dotnet-sdk_6
          dotnet-runtime_6
          xorg.libX11
          xorg.libX11.dev
          xorg.xorgserver
          xorg.libXcursor
          xorg.libXcursor.dev
          xorg.xrandr
          xorg.libXrandr
          xorg.libXrandr.out
          xorg.libXrandr.dev
          xorg.libXi
          xorg.libXi.dev
          xorg.libXext
          xorg.libXext.dev
          xorg.libICE
          xorg.libICE.dev
          xorg.libSM
          fontconfig
          libz
          libz.dev
        ];
      shellHook = ''
        export LD_LIBRARY_PATH=${pkgs.lib.makeLibraryPath buildInputs}
      '';
      };
    };
}

I'm not sure if both lib and lib.dev are required in buildInputs.

For anyone encountering this in the future, the libraries Avalonia requires to launch are libX11, xorgserver, libXcursor, libXrandr, libXi, libXext, libICE, libSM, libz, and fontconfig