From dfa34d93769703cd099a0f2f86cb39c67a4d0f41 Mon Sep 17 00:00:00 2001
From: Eman Resu <78693624+quatquatt@users.noreply.github.com>
Date: Fri, 1 May 2026 16:13:59 -0400
Subject: [PATCH] stdenv.mkDerivation: move attrNames out of happy path

---
 pkgs/stdenv/generic/make-derivation.nix | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pkgs/stdenv/generic/make-derivation.nix b/pkgs/stdenv/generic/make-derivation.nix
index ca9dc2a29a7a..a3bef62d4d71 100644
--- a/pkgs/stdenv/generic/make-derivation.nix
+++ b/pkgs/stdenv/generic/make-derivation.nix
@@ -26,6 +26,7 @@ let
     getDev
     head
     foldl'
+    intersectAttrs
     isAttrs
     isBool
     isDerivation
@@ -909,13 +910,13 @@ let
 
       checkedEnv =
         let
-          overlappingNames = attrNames (builtins.intersectAttrs env' derivationArg);
+          overlappingArgs = intersectAttrs env' derivationArg;
         in
         assert
           (isAttrs env && !isDerivation env)
           || throw "`env` must be an attribute set of environment variables. Set `env.env` or pick a more specific name.";
         assert
-          (overlappingNames == [ ])
+          (overlappingArgs == { })
           || throw (
             let
               errors = lib.concatMapStringsSep "\n" (
@@ -923,7 +924,7 @@ let
                 "  - ${name}: in `env`: ${lib.generators.toPretty { } env'.${name}}; in derivation arguments: ${
                     lib.generators.toPretty { } derivationArg.${name}
                   }"
-              ) overlappingNames;
+              ) (attrNames overlappingArgs);
 
             in
             "The `env` attribute set cannot contain any attributes passed to derivation. The following attributes are overlapping:\n${errors}"