From e74c1dad9dee26a72feb1f693c296df94194f25d Mon Sep 17 00:00:00 2001
From: h7x4 <h7x4@nani.wtf>
Date: Thu, 30 Jul 2026 23:48:18 +0900
Subject: [PATCH] lib: improve implementation of `overrideExisting`

---
 lib/attrsets.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/attrsets.nix b/lib/attrsets.nix
index d006ed79a2ae..c9a32bb58fe1 100644
--- a/lib/attrsets.nix
+++ b/lib/attrsets.nix
@@ -1863,7 +1863,7 @@ rec {
 
     :::
   */
-  overrideExisting = old: new: mapAttrs (name: value: new.${name} or value) old;
+  overrideExisting = old: new: old // intersectAttrs old new;
 
   /**
     Turns a list of strings into a human-readable description of those