From 84b70a6fb0ad883554c4e452edac0c37a854b2e1 Mon Sep 17 00:00:00 2001
From: Hamish Mackenzie <Hamish.K.Mackenzie@gmail.com>
Date: Thu, 13 Jul 2023 16:41:19 +1200
Subject: [PATCH] Fix building stack projects with hix

The default compiler-nix-name provided for hix projects conflicts with the one implied by the `stack.yaml` `resolver`.

Fixes #1997
---
 modules/hix-project.nix | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/modules/hix-project.nix b/modules/hix-project.nix
index 3b40f65971..62db5e9bbd 100644
--- a/modules/hix-project.nix
+++ b/modules/hix-project.nix
@@ -1,4 +1,4 @@
-{ lib, ... }: {
+{ config, lib, ... }: {
   _file = "haskell.nix/modules/hix-project.nix";
   options = {
     # These are options that only the Hix command wrappers use. If you make a flake
@@ -40,8 +40,10 @@
     };
   };
 
-  # Default values for other project options (things that do not have defaults for non hix projects)
-  config = {
-    compiler-nix-name = lib.mkDefault "ghc8107";
+  # Default value for compiler-nix-name (does not have a default for non hix projects).
+  # Stack projects do not require a default as the `resolver` in the `stack.yaml`
+  # specifies one.
+  config = lib.mkIf (!config ? "stackYaml") {
+    compiler-nix-name = lib.mkDefault "ghc945";
   };
 }