From 0ebb19509e64a51c5cd6f86a32e3c859f40c8941 Mon Sep 17 00:00:00 2001
From: shivaraj-bh <sbh69840@gmail.com>
Date: Tue, 13 Feb 2024 11:29:01 +0530
Subject: [PATCH] settings: add removeReferencesTo

This setting helps remove unnecessary dependencies to your haskell package that
bloats up the final closure size

Source: https://github.com/srid/emanote/blob/5623bb3814e382dfea7ffd21d3da25c2d3179001/nix/removeReferencesTo.nix#L9
---
 nix/modules/project/settings/all.nix | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/nix/modules/project/settings/all.nix b/nix/modules/project/settings/all.nix
index a1a9c663..e5e2ad86 100644
--- a/nix/modules/project/settings/all.nix
+++ b/nix/modules/project/settings/all.nix
@@ -311,6 +311,28 @@ in
       impl = triggerRebuild;
     };
 
+    removeReferencesTo = {
+      type = types.listOf types.package;
+      description = ''
+        Packages to remove references to.
+
+        This is useful to ditch unnecessary data dependencies from your Haskell
+        executable so as to reduce its closure size.
+
+        cf.
+        - https://github.com/NixOS/nixpkgs/pull/204675
+        - https://srid.ca/remove-references-to
+      '';
+      impl = disallowedReferences: drv:
+        drv.overrideAttrs (old: rec {
+          inherit disallowedReferences;
+          postInstall = (old.postInstall or "") + ''
+            ${lib.concatStrings (map (e: "echo Removing reference to: ${e}\n") disallowedReferences)}
+            ${lib.concatStrings (map (e: "remove-references-to -t ${e} $out/bin/*\n") disallowedReferences)}
+          '';
+        });
+    };
+
     # When none of the above settings is suitable:
     custom = {
       type = types.functionTo types.package;