Let's try xonsh

home/default.nix

@@ -8,7 +8,6 @@
   home-manager.users.artemis = {
     imports = [
       ./dirs.nix
-      ./fish.nix
       ./git.nix
       ./gpg.nix
       ./gtk.nix

home/fish.nix

@@ -1,16 +0,0 @@
-{ pkgs, ... }:
-{
-  programs.fish = {
-    enable = true;
-    interactiveShellInit = "set -g -x GPG_TTY (tty)";
-    shellAliases = {
-      cat = "bat";
-      ls = "eza";
-      nix-fish = "nix-shell --command fish";
-    };
-  };
-  home.packages = with pkgs; [
-    bat
-    eza
-  ];
-}

sets/base.nix

@@ -1,6 +1,5 @@
 {
   config,
-  pkgs,
   lib,
   inputs,
   ...
@@ -11,6 +10,7 @@
     inputs.lix-module.nixosModules.default
     inputs.private.nixosModules.base
     inputs.private.nixosModules.substituter
+    ./xonsh.nix
   ];
 
   nix = {
@@ -85,7 +85,6 @@
   time.timeZone = "Etc/UTC";
   environment.shellAliases.cp = "cp --reflink=auto --sparse=always";
   networking.firewall.enable = false;
-  programs.fish.enable = true;
 
   users = {
     users.artemis = {
@@ -96,7 +95,6 @@
         "wheel"
         "artemis"
       ];
-      shell = pkgs.fish;
       # hashedPassword set in private
     };
     groups.artemis.gid = config.users.users.artemis.uid;

sets/nvim.nix

@@ -50,7 +50,6 @@ lib.setAttrByPath setPath (
     };
     extraPlugins = with pkgs.vimPlugins; [
       vim-fetch
-      vim-fish
       vim-flatbuffers
       vim-nftables
       vim-protobuf

sets/xonsh.nix

@@ -0,0 +1,45 @@
+{ pkgs, ... }:
+let
+  xonsh-direnv =
+    ps:
+    ps.buildPythonPackage rec {
+      pname = "xonsh-direnv";
+      version = "1.6.1";
+      src = pkgs.fetchPypi {
+        inherit pname version;
+        hash = "sha256-Nt8Da1EtMVWZ9mbBDjys7HDutLYifwoQ1HVmI5CN2Ww=";
+      };
+    };
+  xontrib-fish-completer =
+    ps:
+    ps.buildPythonPackage rec {
+      pname = "xontrib-fish-completer";
+      version = "0.0.1";
+      src = pkgs.fetchPypi {
+        inherit pname version;
+        hash = "sha256-Kr1iolx6DxqgxVNtXwwfggkLrbH9BlilGAYZahvR+3Y=";
+      };
+
+      patchPhase = "sed -i -e 's/^dependencies.*$/dependencies = []/' pyproject.toml";
+    };
+in
+{
+  # We need fish for fish completions
+  programs.fish.enable = true;
+
+  users.users.artemis.shell = "/run/current-system/sw/bin/xonsh";
+
+  programs.xonsh = {
+    enable = true;
+    config = ''
+      $UPDATE_OS_ENVIRON = True
+      xontrib load direnv fish_completer
+    '';
+    package = pkgs.xonsh.override {
+      extraPackages = ps: [
+        (xonsh-direnv ps)
+        (xontrib-fish-completer ps)
+      ];
+    };
+  };
+}