From 3cfe2fe9668b430ab7e2f1f36e5a3765fef145de Mon Sep 17 00:00:00 2001
From: Sridhar Ratnakumar <srid@srid.ca>
Date: Wed, 27 Apr 2022 15:03:34 -0400
Subject: [PATCH] Use pkgs.nix-gitignore

---
 flake.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/flake.nix b/flake.nix
index 951b39b..f19e36a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -26,11 +26,15 @@
           #   nix-env -f "<nixpkgs>" -qaP -A haskell.compiler
           hp = pkgs.haskellPackages; # pkgs.haskell.packages.ghc921;
 
+          # Paths to ignore when building the cabal package.
+          # FIXME: Why does changing any of this this retrigger Nix builds anyway?
+          ignorePatterns = [ "*.nix" "flake.lock" "*.md" "fourmolu.yaml" "hie.yaml" "bin" ".envrc" ".ghcid" ".gitattributes" ".github" ".gitignore" ".vscode" ];
+
           project = returnShellEnv:
             hp.developPackage {
               inherit returnShellEnv;
               name = "haskell-template";
-              root = ./.;
+              root = pkgs.nix-gitignore.gitignoreSource ignorePatterns ./.;
               withHoogle = false;
               overrides = self: super: with pkgs.haskell.lib; {
                 # Use callCabal2nix to override Haskell dependencies here