From d7dff39146a2bfa4f9ecc2e9c2c88a83894910de Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Mon, 6 Apr 2026 12:25:46 +0200
Subject: [PATCH 1/2] pkgs/splice: bring mapAttrs into scope

... and take it from lib. Inconsequential, but it's a good convention
because it has occasional improvements to builtins' intentionally
highly unchanging behavior.
---
 pkgs/top-level/splice.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pkgs/top-level/splice.nix b/pkgs/top-level/splice.nix
index 5468d23c377d..c08aceaa2abf 100644
--- a/pkgs/top-level/splice.nix
+++ b/pkgs/top-level/splice.nix
@@ -18,6 +18,7 @@ lib: pkgs: actuallySplice:
 
 let
   inherit (lib.customisation) mapCrossIndex renameCrossIndexFrom;
+  inherit (lib) mapAttrs;
 
   spliceReal =
     inputs:
@@ -66,7 +67,7 @@ let
           # `__functor__` for functions instead.
           defaultValue;
     in
-    builtins.mapAttrs merge mash;
+    mapAttrs merge mash;
 
   splicePackages =
     {

From 3ae1aa996857e2bc535f79e9c4b6208091d06955 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Mon, 6 Apr 2026 12:27:06 +0200
Subject: [PATCH 2/2] pkgs/splice: drop reference to past code

References to previous states of the code generally only belong in
commit messages.
A reminder or warning to future readers is not needed here.
---
 pkgs/top-level/splice.nix | 2 --
 1 file changed, 2 deletions(-)

diff --git a/pkgs/top-level/splice.nix b/pkgs/top-level/splice.nix
index c08aceaa2abf..718ed9f40f9d 100644
--- a/pkgs/top-level/splice.nix
+++ b/pkgs/top-level/splice.nix
@@ -32,8 +32,6 @@ let
         # The same pkgs sets one probably intends
         // inputs.buildHost
         // inputs.hostTarget;
-      # perf: mapAttrs defers merge calls until a key is selected, avoiding
-      # ~60k eager closures that listToAttrs+map would create.
       merge =
         name: defaultValue:
         let