nixForLinking: init

Overlays for CppNix nightly, Lix, or Tvix want to change the default Nix
implementation in Nixpkgs by overriding `pkgs.nix`. However, some
packages link against the internal/unstable CppNix APIs directly, and
these packages will break if built with different versions or
implementations of Nix.

If you want to swap out the Nix implementation in your package set, you
don't want these packages to break. Therefore, some packages will refer
to `nixForLinking` explicitly, at least until these dependencies can be
sorted out.

The addition of an explicit `nixForLinking` attribute decoupled from
`nix`, which is just "a Nix implementation", will help Nix
implementation maintainers test Nix implementations in Nixpkgs with
minimal hassle.

Author: 9999years

pkgs/build-support/node/fetch-yarn-deps/default.nix

@@ -17,7 +17,7 @@
   makeSetupHook,
   cacert,
   callPackage,
-  nix,
+  nixForLinking,
 }:
 
 let
@@ -54,7 +54,7 @@ in
           lib.makeBinPath [
             coreutils
             nix-prefetch-git
-            nix
+            nixForLinking
           ]
         }
 

pkgs/by-name/at/attic-client/package.nix

@@ -2,7 +2,7 @@
   lib,
   rustPlatform,
   fetchFromGitHub,
-  nix,
+  nixForLinking,
   nixosTests,
   boost,
   pkg-config,
@@ -29,7 +29,7 @@ rustPlatform.buildRustPackage {
 
   buildInputs =
     [
-      nix
+      nixForLinking
       boost
     ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin (
@@ -44,7 +44,7 @@ rustPlatform.buildRustPackage {
   useFetchCargoVendor = true;
 
   ATTIC_DISTRIBUTOR = "nixpkgs";
-  NIX_INCLUDE_PATH = "${lib.getDev nix}/include";
+  NIX_INCLUDE_PATH = "${lib.getDev nixForLinking}/include";
 
   # Attic interacts with Nix directly and its tests require trusted-user access
   # to nix-daemon to import NARs, which is not possible in the build sandbox.

pkgs/by-name/nu/nurl/package.nix

@@ -8,7 +8,7 @@
   darwin,
   gitMinimal,
   mercurial,
-  nix,
+  nixForLinking,
 }:
 
 rustPlatform.buildRustPackage rec {
@@ -47,7 +47,7 @@ rustPlatform.buildRustPackage rec {
         lib.makeBinPath [
           gitMinimal
           mercurial
-          nix
+          nixForLinking
         ]
       }
     installManPage artifacts/nurl.1

pkgs/development/tools/language-servers/nixd/default.nix

@@ -8,7 +8,7 @@
   llvmPackages,
   meson,
   ninja,
-  nix,
+  nixForLinking,
   nix-update-script,
   nixd,
   nixf,
@@ -101,12 +101,12 @@ in
       ];
 
       buildInputs = [
-        nix
+        nixForLinking
         gtest
         boost
       ];
 
-      env.CXXFLAGS = "-include ${nix.dev}/include/nix/config.h";
+      env.CXXFLAGS = "-include ${nixForLinking.dev}/include/nix/config.h";
 
       passthru.tests.pkg-config = testers.hasPkgConfigModules {
         package = nixt;
@@ -127,7 +127,7 @@ in
       sourceRoot = "${common.src.name}/nixd";
 
       buildInputs = [
-        nix
+        nixForLinking
         nixf
         nixt
         llvmPackages.llvm
@@ -137,7 +137,7 @@ in
 
       nativeBuildInputs = common.nativeBuildInputs ++ [ cmake ];
 
-      env.CXXFLAGS = "-include ${nix.dev}/include/nix/config.h";
+      env.CXXFLAGS = "-include ${nixForLinking.dev}/include/nix/config.h";
 
       # See https://github.com/nix-community/nixd/issues/519
       doCheck = false;

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

@@ -3,7 +3,7 @@
   stdenv,
   fetchFromGitHub,
   rustPlatform,
-  nix,
+  nixForLinking,
   nlohmann_json,
   boost,
   graphviz,
@@ -27,13 +27,13 @@ rustPlatform.buildRustPackage rec {
 
   doCheck = true;
   nativeCheckInputs = [
-    nix
+    nixForLinking
     graphviz
   ];
 
   buildInputs = [
     boost
-    nix
+    nixForLinking
     nlohmann_json
   ] ++ lib.optionals stdenv.hostPlatform.isDarwin [ Security ];
 

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

@@ -1,5 +1,18 @@
 { lib, stdenv, makeWrapper, buildEnv
-, bash, breezy, coreutils, cvs, findutils, gawk, git, git-lfs, gnused, mercurial, nix, subversion
+, bash, breezy, coreutils, cvs, findutils, gawk, git, git-lfs, gnused, mercurial
+, # FIXME: These scripts should not depend on Nix, they should depend on a
+  # `.nar` hasher compatible with Nix.
+  #
+  # The fact that these scripts depend on Nix means that e.g. Chromium depends
+  # on Nix.
+  #
+  # Also should be fixed:
+  # - prefetch-yarn-deps
+  # - nurl, nix-init
+  #
+  # Gridlock is one such candidate: https://github.com/lf-/gridlock
+  nixForLinking
+, subversion
 }:
 
 let mkPrefetchScript = tool: src: deps:
@@ -15,7 +28,7 @@ let mkPrefetchScript = tool: src: deps:
     installPhase = ''
       install -vD ${src} $out/bin/$name;
       wrapProgram $out/bin/$name \
-        --prefix PATH : ${lib.makeBinPath (deps ++ [ coreutils gnused nix ])} \
+        --prefix PATH : ${lib.makeBinPath (deps ++ [ coreutils gnused nixForLinking ])} \
         --set HOME /homeless-shelter
     '';
 

pkgs/top-level/all-packages.nix

@@ -17562,6 +17562,16 @@ with pkgs;
 
   nix = nixVersions.stable;
 
+  # Overlays for CppNix nightly, Lix, or Tvix want to change the default Nix
+  # implementation in Nixpkgs by overriding `pkgs.nix`. However, some packages
+  # link against the internal/unstable CppNix APIs directly, and these packages
+  # will break if built with different versions or implementations of Nix.
+  #
+  # If you want to swap out the Nix implementation in your package set, you
+  # don't want these packages to break. Therefore, some packages will refer to
+  # `nixForLinking` explicitly, at least until these dependencies can be sorted out.
+  nixForLinking = nixVersions.stable;
+
   nixStatic = pkgsStatic.nix;
 
   lixVersions = recurseIntoAttrs (callPackage ../tools/package-management/lix {