try with flake info first

.build.yml

@@ -8,7 +8,9 @@ secrets:
 tasks:
   - check: |
         cd dotfiles
+        nix-shell --pure --run 'nix-experimental flake info'
         nix-shell --pure --run 'nix-experimental flake check'
+
   - github_push: |
         set +xv
         cd dotfiles

nixos/home-manager/programs/emacs/home.nix

@@ -13,12 +13,15 @@
     (progn (add-hook 'comint-preoutput-filter-functions 'xterm-color-filter)
        (setq comint-output-filter-functions (remove 'ansi-color-process-output comint-output-filter-functions)))
 
-
     (set-terminal-parameter nil 'background-mode 'dark)
     (xterm-mouse-mode 1)
 
     (require 'evil)
     (evil-mode 1)
+
+    (setq custom-tab-width 2)
+    (setq indent-tabs-mode nil)
+
   '';
   programs.emacs = {
     enable = true;