From d9ce06790d3d58ee8139017658774e98f359e8c3 Mon Sep 17 00:00:00 2001
From: Yuriy Taraday <yuriy.taraday@tweag.io>
Date: Fri, 1 Aug 2025 15:49:53 +0200
Subject: [PATCH 1/2] stdenv: Remove extra merge operator in meta

This operator merges two attrsets without any conditions, and leads to
more operations and allocations.
---
 pkgs/stdenv/generic/check-meta.nix | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pkgs/stdenv/generic/check-meta.nix b/pkgs/stdenv/generic/check-meta.nix
index b1433dac99b66..f5f229290dec9 100644
--- a/pkgs/stdenv/generic/check-meta.nix
+++ b/pkgs/stdenv/generic/check-meta.nix
@@ -622,8 +622,7 @@ let
       # if you add a new maintainer or team attribute please ensure that this expectation is still met.
       maintainers =
         attrs.meta.maintainers or [ ] ++ concatMap (team: team.members or [ ]) attrs.meta.teams or [ ];
-    }
-    // {
+
       # Expose the result of the checks for everyone to see.
       unfree = hasUnfreeLicense attrs;
       broken = isMarkedBroken attrs;

From 60d2cc07ad97e33578d9cd7f64c9df1ceae058ce Mon Sep 17 00:00:00 2001
From: Yuriy Taraday <yuriy.taraday@tweag.io>
Date: Fri, 1 Aug 2025 17:56:36 +0200
Subject: [PATCH 2/2] stdenv: add all positions to meta without merges

Remove usage of filterAttrs and two more attrset merges. Saves more
time and memory.
---
 pkgs/stdenv/generic/check-meta.nix | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/pkgs/stdenv/generic/check-meta.nix b/pkgs/stdenv/generic/check-meta.nix
index f5f229290dec9..213da04d76956 100644
--- a/pkgs/stdenv/generic/check-meta.nix
+++ b/pkgs/stdenv/generic/check-meta.nix
@@ -26,7 +26,6 @@ let
     isAttrs
     isString
     mapAttrs
-    filterAttrs
     ;
 
   inherit (lib.lists)
@@ -576,6 +575,8 @@ let
     let
       outputs = attrs.outputs or [ "out" ];
       hasOutput = out: builtins.elem out outputs;
+      maintainersPosition = builtins.unsafeGetAttrPos "maintainers" (attrs.meta or { });
+      teamsPosition = builtins.unsafeGetAttrPos "teams" (attrs.meta or { });
     in
     {
       # `name` derivation attribute includes cross-compilation cruft,
@@ -604,19 +605,17 @@ let
         )
       ]
       ++ optional (hasOutput "man") "man";
-    }
-    // (filterAttrs (_: v: v != null) {
+
       # CI scripts look at these to determine pings. Note that we should filter nulls out of this,
       # or nix-env complains: https://github.com/NixOS/nix/blob/2.18.8/src/nix-env/nix-env.cc#L963
-      maintainersPosition = builtins.unsafeGetAttrPos "maintainers" (attrs.meta or { });
-      teamsPosition = builtins.unsafeGetAttrPos "teams" (attrs.meta or { });
-    })
-    // attrs.meta or { }
-    # Fill `meta.position` to identify the source location of the package.
-    // optionalAttrs (pos != null) {
-      position = pos.file + ":" + toString pos.line;
+      ${if maintainersPosition == null then null else "maintainersPosition"} = maintainersPosition;
+      ${if teamsPosition == null then null else "teamsPosition"} = teamsPosition;
     }
+    // attrs.meta or { }
     // {
+      # Fill `meta.position` to identify the source location of the package.
+      ${if pos == null then null else "position"} = pos.file + ":" + toString pos.line;
+
       # Maintainers should be inclusive of teams.
       # Note that there may be external consumers of this API (repology, for instance) -
       # if you add a new maintainer or team attribute please ensure that this expectation is still met.