nixVersions.nix_2_26: Fix cross and static

lib/tests/nix-for-tests.nix

@@ -12,5 +12,21 @@
 # See also: https://github.com/NixOS/nix/issues/7582
 
 builtins.mapAttrs (
-  _: pkg: if builtins.isAttrs pkg then pkg.override { withAWS = false; } else pkg
+  attr: pkg:
+  if
+    # TODO descend in `nixComponents_*` and override `nix-store`. Also
+    # need to introduce the flag needed to do that with.
+    #
+    # This must be done before Nix 2.26 and beyond becomes the default.
+    !(builtins.elem attr [
+      "nixComponents_2_26"
+      "nix_2_26"
+      "latest"
+    ])
+    # There may-be non-package things, like functions, in there too
+    && builtins.isAttrs pkg
+  then
+    pkg.override { withAWS = false; }
+  else
+    pkg
 ) pkgs.nixVersions

pkgs/tools/package-management/nix/default.nix

@@ -5,6 +5,7 @@
   aws-sdk-cpp,
   boehmgc,
   callPackage,
+  generateSplicesForMkScope,
   fetchFromGitHub,
   fetchpatch2,
   runCommand,
@@ -199,6 +200,19 @@ let
       };
     };
 
+  # Factored out for when we have package sets for multiple versions of
+  # Nix.
+  #
+  # `nixPackages_*` would be the most regular name, analogous to
+  # `linuxPackages_*`, especially if we put other 3rd-party software in
+  # here, but `nixPackages_*` would also be *very* confusing to humans!
+  generateSplicesForNixComponents =
+    nixComponentsAttributeName:
+    generateSplicesForMkScope [
+      "nixVersions"
+      nixComponentsAttributeName
+    ];
+
 in
 lib.makeExtensible (
   self:
@@ -235,10 +249,17 @@ lib.makeExtensible (
         self_attribute_name = "nix_2_25";
       };
 
-      nix_2_26 = addTests "nix_2_26" (
-        callPackage ./vendor/2_26/componentized.nix { inherit (self.nix_2_24.meta) maintainers; }
+      nixComponents_2_26 = (
+        callPackage ./vendor/2_26/componentized.nix {
+          inherit (self.nix_2_24.meta) maintainers;
+          otherSplices = generateSplicesForNixComponents "nixComponents_2_26";
+        }
       );
 
+      # Note, this might eventually become an alias, as packages should
+      # depend on the components they need in `nixComponents_2_26`.
+      nix_2_26 = addTests "nix_2_26" self.nixComponents_2_26.nix-everything;
+
       git = common rec {
         version = "2.25.0";
         suffix = "pre20241101_${lib.substring 0 8 src.rev}";

pkgs/tools/package-management/nix/vendor/2_26/componentized.nix

@@ -7,7 +7,7 @@
   pkgs,
   stdenv,
   maintainers,
-  ...
+  otherSplices,
 }:
 let
   officialRelease = true;
@@ -24,7 +24,7 @@ let
         inherit (nixDependencies) newScope;
       }
       {
-        otherSplices = generateSplicesForMkScope "nixComponents";
+        inherit otherSplices;
         f = import ./packaging/components.nix {
           inherit
             lib
@@ -45,11 +45,13 @@ let
         inherit newScope; # layered directly on pkgs, unlike nixComponents above
       }
       {
-        otherSplices = generateSplicesForMkScope "nixDependencies";
+        # Technically this should point to the nixDependencies set only, but
+        # this is ok as long as the scopes don't intersect.
+        inherit otherSplices;
         f = import ./dependencies.nix {
           inherit pkgs;
           inherit stdenv;
         };
       };
 in
-(nixComponents.overrideSource src).nix-everything
+nixComponents.overrideSource src