diff --git a/pkgs/tools/package-management/nix/2_26/.version b/pkgs/tools/package-management/nix/2_26/.version
new file mode 100644
index 0000000000000..53effa101a050
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/.version
@@ -0,0 +1 @@
+2.26.1
\ No newline at end of file
diff --git a/pkgs/tools/package-management/nix/2_26/componentized.nix b/pkgs/tools/package-management/nix/2_26/componentized.nix
new file mode 100644
index 0000000000000..48f2d052d36f9
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/componentized.nix
@@ -0,0 +1,49 @@
+{
+  lib,
+  fetchFromGitHub,
+  splicePackages,
+  generateSplicesForMkScope,
+  newScope,
+  pkgs,
+  stdenv,
+  ...
+}:
+let
+  officialRelease = true;
+  src = fetchFromGitHub (builtins.fromJSON (builtins.readFile ./source.json));
+
+  # A new scope, so that we can use `callPackage` to inject our own interdependencies
+  # without "polluting" the top level "`pkgs`" attrset.
+  # This also has the benefit of providing us with a distinct set of packages
+  # we can iterate over.
+  nixComponents =
+    lib.makeScopeWithSplicing'
+      {
+        inherit splicePackages;
+        inherit (nixDependencies) newScope;
+      }
+      {
+        otherSplices = generateSplicesForMkScope "nixComponents";
+        f = import ./packaging/components.nix {
+          inherit lib officialRelease src;
+        };
+      };
+
+  # The dependencies are in their own scope, so that they don't have to be
+  # in Nixpkgs top level `pkgs` or `nixComponents`.
+  nixDependencies =
+    lib.makeScopeWithSplicing'
+      {
+        inherit splicePackages;
+        inherit newScope; # layered directly on pkgs, unlike nixComponents above
+      }
+      {
+        otherSplices = generateSplicesForMkScope "nixDependencies";
+        f = import ./dependencies.nix {
+          inherit pkgs;
+          inherit stdenv;
+          inherit src;
+        };
+      };
+in
+nixComponents.nix-everything
diff --git a/pkgs/tools/package-management/nix/2_26/dependencies.nix b/pkgs/tools/package-management/nix/2_26/dependencies.nix
new file mode 100644
index 0000000000000..73739e2edcc5b
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/dependencies.nix
@@ -0,0 +1,182 @@
+# These overrides are applied to the dependencies of the Nix components.
+
+{
+  src,
+
+  # The raw Nixpkgs, not affected by this scope
+  pkgs,
+
+  stdenv,
+}:
+
+let
+  prevStdenv = stdenv;
+in
+
+let
+  inherit (pkgs) lib;
+
+  root = ./.;
+
+  stdenv = if prevStdenv.isDarwin && prevStdenv.isx86_64 then darwinStdenv else prevStdenv;
+
+  # Fix the following error with the default x86_64-darwin SDK:
+  #
+  #     error: aligned allocation function of type 'void *(std::size_t, std::align_val_t)' is only available on macOS 10.13 or newer
+  #
+  # Despite the use of the 10.13 deployment target here, the aligned
+  # allocation function Clang uses with this setting actually works
+  # all the way back to 10.6.
+  darwinStdenv = pkgs.overrideSDK prevStdenv { darwinMinVersion = "10.13"; };
+
+  resolveRelPath = p: lib.path.removePrefix root p;
+  resolvePath = p: src + "/${resolveRelPath p}";
+
+  # Indirection for Nixpkgs to override when package.nix files are vendored
+  # fileset filtering is not possible without IFD on src, so we ignore the fileset
+  # and produce a path containing _more_, but the extra files generally won't be
+  # accessed.
+  # The Nix flake uses fileset.toSource for this.
+  filesetToSource = { root, fileset }: resolvePath root;
+
+  /**
+    Given a set of layers, create a mkDerivation-like function
+  */
+  mkPackageBuilder =
+    exts: userFn: stdenv.mkDerivation (lib.extends (lib.composeManyExtensions exts) userFn);
+
+  localSourceLayer =
+    finalAttrs: prevAttrs:
+    let
+      workDirPath =
+        # Ideally we'd pick finalAttrs.workDir, but for now `mkDerivation` has
+        # the requirement that everything except passthru and meta must be
+        # serialized by mkDerivation, which doesn't work for this.
+        prevAttrs.workDir;
+
+      workDirSubpath = resolveRelPath workDirPath;
+      # sources = assert prevAttrs.fileset._type == "fileset"; prevAttrs.fileset;
+      # src = lib.fileset.toSource { fileset = sources; inherit root; };
+
+    in
+    {
+      sourceRoot = "${src.name}/" + workDirSubpath;
+      inherit src;
+
+      # Clear what `derivation` can't/shouldn't serialize; see prevAttrs.workDir.
+      fileset = null;
+      workDir = null;
+    };
+
+  mesonLayer = finalAttrs: prevAttrs: {
+    # NOTE:
+    # As of https://github.com/NixOS/nixpkgs/blob/8baf8241cea0c7b30e0b8ae73474cb3de83c1a30/pkgs/by-name/me/meson/setup-hook.sh#L26,
+    # `mesonBuildType` defaults to `plain` if not specified. We want our Nix-built binaries to be optimized by default.
+    # More on build types here: https://mesonbuild.com/Builtin-options.html#details-for-buildtype.
+    mesonBuildType = "release";
+    # NOTE:
+    # Users who are debugging Nix builds are expected to set the environment variable `mesonBuildType`, per the
+    # guidance in https://github.com/NixOS/nix/blob/8a3fc27f1b63a08ac983ee46435a56cf49ebaf4a/doc/manual/source/development/debugging.md?plain=1#L10.
+    # For this reason, we don't want to refer to `finalAttrs.mesonBuildType` here, but rather use the environment variable.
+    preConfigure =
+      prevAttrs.preConfigure or ""
+      +
+        lib.optionalString
+          (
+            !stdenv.hostPlatform.isWindows
+            # build failure
+            && !stdenv.hostPlatform.isStatic
+            # LTO breaks exception handling on x86-64-darwin.
+            && stdenv.system != "x86_64-darwin"
+          )
+          ''
+            case "$mesonBuildType" in
+            release|minsize) appendToVar mesonFlags "-Db_lto=true"  ;;
+            *)               appendToVar mesonFlags "-Db_lto=false" ;;
+            esac
+          '';
+    nativeBuildInputs = [
+      pkgs.buildPackages.meson
+      pkgs.buildPackages.ninja
+    ] ++ prevAttrs.nativeBuildInputs or [ ];
+    mesonCheckFlags = prevAttrs.mesonCheckFlags or [ ] ++ [
+      "--print-errorlogs"
+    ];
+  };
+
+  mesonBuildLayer = finalAttrs: prevAttrs: {
+    nativeBuildInputs = prevAttrs.nativeBuildInputs or [ ] ++ [
+      pkgs.buildPackages.pkg-config
+    ];
+    separateDebugInfo = !stdenv.hostPlatform.isStatic;
+    hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+    env =
+      prevAttrs.env or { }
+      // lib.optionalAttrs (
+        stdenv.isLinux
+        && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")
+        && !(stdenv.hostPlatform.useLLVM or false)
+      ) { LDFLAGS = "-fuse-ld=gold"; };
+  };
+
+  mesonLibraryLayer = finalAttrs: prevAttrs: {
+    outputs = prevAttrs.outputs or [ "out" ] ++ [ "dev" ];
+  };
+
+  # Work around weird `--as-needed` linker behavior with BSD, see
+  # https://github.com/mesonbuild/meson/issues/3593
+  bsdNoLinkAsNeeded =
+    finalAttrs: prevAttrs:
+    lib.optionalAttrs stdenv.hostPlatform.isBSD {
+      mesonFlags = [ (lib.mesonBool "b_asneeded" false) ] ++ prevAttrs.mesonFlags or [ ];
+    };
+
+  miscGoodPractice = finalAttrs: prevAttrs: {
+    strictDeps = prevAttrs.strictDeps or true;
+    enableParallelBuilding = true;
+  };
+in
+scope: {
+  inherit stdenv;
+
+  aws-sdk-cpp =
+    (pkgs.aws-sdk-cpp.override {
+      apis = [
+        "s3"
+        "transfer"
+      ];
+      customMemoryManagement = false;
+    }).overrideAttrs
+      {
+        # only a stripped down version is built, which takes a lot less resources
+        # to build, so we don't need a "big-parallel" machine.
+        requiredSystemFeatures = [ ];
+      };
+
+  boehmgc = pkgs.boehmgc.override {
+    enableLargeConfig = true;
+  };
+
+  inherit resolvePath filesetToSource;
+
+  mkMesonDerivation = mkPackageBuilder [
+    miscGoodPractice
+    localSourceLayer
+    mesonLayer
+  ];
+  mkMesonExecutable = mkPackageBuilder [
+    miscGoodPractice
+    bsdNoLinkAsNeeded
+    localSourceLayer
+    mesonLayer
+    mesonBuildLayer
+  ];
+  mkMesonLibrary = mkPackageBuilder [
+    miscGoodPractice
+    bsdNoLinkAsNeeded
+    localSourceLayer
+    mesonLayer
+    mesonBuildLayer
+    mesonLibraryLayer
+  ];
+}
diff --git a/pkgs/tools/package-management/nix/2_26/doc/manual/package.nix b/pkgs/tools/package-management/nix/2_26/doc/manual/package.nix
new file mode 100644
index 0000000000000..8f5d0dfe1370f
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/doc/manual/package.nix
@@ -0,0 +1,75 @@
+{
+  lib,
+  mkMesonDerivation,
+
+  meson,
+  ninja,
+  lowdown-unsandboxed,
+  mdbook,
+  mdbook-linkcheck,
+  jq,
+  python3,
+  rsync,
+  nix-cli,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonDerivation (finalAttrs: {
+  pname = "nix-manual";
+  inherit version;
+
+  workDir = ./.;
+  fileset =
+    fileset.difference
+      (fileset.unions [
+        ../../.version
+        # Too many different types of files to filter for now
+        ../../doc/manual
+        ./.
+      ])
+      # Do a blacklist instead
+      ../../doc/manual/package.nix;
+
+  # TODO the man pages should probably be separate
+  outputs = [
+    "out"
+    "man"
+  ];
+
+  # Hack for sake of the dev shell
+  passthru.externalNativeBuildInputs = [
+    meson
+    ninja
+    (lib.getBin lowdown-unsandboxed)
+    mdbook
+    mdbook-linkcheck
+    jq
+    python3
+    rsync
+  ];
+
+  nativeBuildInputs = finalAttrs.passthru.externalNativeBuildInputs ++ [
+    nix-cli
+  ];
+
+  preConfigure = ''
+    chmod u+w ./.version
+    echo ${finalAttrs.version} > ./.version
+  '';
+
+  postInstall = ''
+    mkdir -p ''$out/nix-support
+    echo "doc manual ''$out/share/doc/nix/manual" >> ''$out/nix-support/hydra-build-products
+  '';
+
+  meta = {
+    platforms = lib.platforms.all;
+  };
+})
diff --git a/pkgs/tools/package-management/nix/2_26/packaging/components.nix b/pkgs/tools/package-management/nix/2_26/packaging/components.nix
new file mode 100644
index 0000000000000..57932617f827e
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/packaging/components.nix
@@ -0,0 +1,68 @@
+{
+  lib,
+  src,
+  officialRelease,
+}:
+
+scope:
+
+let
+  inherit (scope) callPackage;
+
+  baseVersion = lib.fileContents ../.version;
+
+  versionSuffix = lib.optionalString (!officialRelease) "pre";
+
+  fineVersionSuffix =
+    lib.optionalString (!officialRelease)
+      "pre${
+        builtins.substring 0 8 (src.lastModifiedDate or src.lastModified or "19700101")
+      }_${src.shortRev or "dirty"}";
+
+  fineVersion = baseVersion + fineVersionSuffix;
+in
+
+# This becomes the pkgs.nixComponents attribute set
+{
+  version = baseVersion + versionSuffix;
+  inherit versionSuffix;
+
+  nix-util = callPackage ../src/libutil/package.nix { };
+  nix-util-c = callPackage ../src/libutil-c/package.nix { };
+  nix-util-test-support = callPackage ../src/libutil-test-support/package.nix { };
+  nix-util-tests = callPackage ../src/libutil-tests/package.nix { };
+
+  nix-store = callPackage ../src/libstore/package.nix { };
+  nix-store-c = callPackage ../src/libstore-c/package.nix { };
+  nix-store-test-support = callPackage ../src/libstore-test-support/package.nix { };
+  nix-store-tests = callPackage ../src/libstore-tests/package.nix { };
+
+  nix-fetchers = callPackage ../src/libfetchers/package.nix { };
+  nix-fetchers-tests = callPackage ../src/libfetchers-tests/package.nix { };
+
+  nix-expr = callPackage ../src/libexpr/package.nix { };
+  nix-expr-c = callPackage ../src/libexpr-c/package.nix { };
+  nix-expr-test-support = callPackage ../src/libexpr-test-support/package.nix { };
+  nix-expr-tests = callPackage ../src/libexpr-tests/package.nix { };
+
+  nix-flake = callPackage ../src/libflake/package.nix { };
+  nix-flake-c = callPackage ../src/libflake-c/package.nix { };
+  nix-flake-tests = callPackage ../src/libflake-tests/package.nix { };
+
+  nix-main = callPackage ../src/libmain/package.nix { };
+  nix-main-c = callPackage ../src/libmain-c/package.nix { };
+
+  nix-cmd = callPackage ../src/libcmd/package.nix { };
+
+  nix-cli = callPackage ../src/nix/package.nix { version = fineVersion; };
+
+  nix-functional-tests = callPackage ../tests/functional/package.nix { version = fineVersion; };
+
+  nix-manual = callPackage ../doc/manual/package.nix { version = fineVersion; };
+  nix-internal-api-docs = callPackage ../src/internal-api-docs/package.nix { version = fineVersion; };
+  nix-external-api-docs = callPackage ../src/external-api-docs/package.nix { version = fineVersion; };
+
+  nix-perl-bindings = callPackage ../src/perl/package.nix { };
+
+  nix-everything = callPackage ../packaging/everything.nix { };
+}
diff --git a/pkgs/tools/package-management/nix/2_26/packaging/everything.nix b/pkgs/tools/package-management/nix/2_26/packaging/everything.nix
new file mode 100644
index 0000000000000..7ac7a156d2269
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/packaging/everything.nix
@@ -0,0 +1,208 @@
+{
+  lib,
+  stdenv,
+  buildEnv,
+
+  nix-util,
+  nix-util-c,
+  nix-util-tests,
+
+  nix-store,
+  nix-store-c,
+  nix-store-tests,
+
+  nix-fetchers,
+  nix-fetchers-tests,
+
+  nix-expr,
+  nix-expr-c,
+  nix-expr-tests,
+
+  nix-flake,
+  nix-flake-c,
+  nix-flake-tests,
+
+  nix-main,
+  nix-main-c,
+
+  nix-cmd,
+
+  nix-cli,
+
+  nix-functional-tests,
+
+  nix-manual,
+  nix-internal-api-docs,
+  nix-external-api-docs,
+
+  nix-perl-bindings,
+
+  testers,
+  runCommand,
+}:
+
+let
+  libs =
+    {
+      inherit
+        nix-util
+        nix-util-c
+        nix-store
+        nix-store-c
+        nix-fetchers
+        nix-expr
+        nix-expr-c
+        nix-flake
+        nix-flake-c
+        nix-main
+        nix-main-c
+        nix-cmd
+        ;
+    }
+    // lib.optionalAttrs
+      (!stdenv.hostPlatform.isStatic && stdenv.buildPlatform.canExecute stdenv.hostPlatform)
+      {
+        # Currently fails in static build
+        inherit
+          nix-perl-bindings
+          ;
+      };
+
+  dev =
+    nixAttrs:
+    stdenv.mkDerivation (finalAttrs: {
+      name = "nix-${nix-cli.version}-dev";
+      pname = "nix";
+      version = nix-cli.version;
+      dontUnpack = true;
+      dontBuild = true;
+      libs = map lib.getDev (lib.attrValues libs);
+      installPhase = ''
+        mkdir -p $out/nix-support
+        echo $libs >> $out/nix-support/propagated-build-inputs
+        echo ${nixAttrs.finalPackage} >> $out/nix-support/propagated-build-inputs
+      '';
+      passthru = {
+        tests = {
+          # TODO: is this supposed to work for a dev output?
+          # pkg-config = testers.hasPkgConfigModules {
+          #   package = finalAttrs.finalPackage;
+          # };
+        };
+
+        # If we were to fully emulate output selection here, we'd confuse the Nix CLIs,
+        # because they rely on `drvPath`.
+        dev = finalAttrs.finalPackage.out;
+        out = nixAttrs.finalPackage.out;
+
+        libs = throw "`nix.dev.libs` is not meant to be used; use `nix.libs` instead.";
+      };
+      meta = {
+        pkgConfigModules = [
+          "nix-cmd"
+          "nix-expr"
+          "nix-expr-c"
+          "nix-fetchers"
+          "nix-flake"
+          "nix-flake-c"
+          "nix-main"
+          "nix-main-c"
+          "nix-store"
+          "nix-store-c"
+          "nix-util"
+          "nix-util-c"
+        ];
+      };
+    });
+  devdoc = buildEnv {
+    name = "nix-${nix-cli.version}-devdoc";
+    paths = [
+      nix-internal-api-docs
+      nix-external-api-docs
+    ];
+  };
+
+in
+(buildEnv {
+  name = "nix-${nix-cli.version}";
+  paths = [
+    nix-cli
+    nix-manual.man
+  ];
+
+  meta.mainProgram = "nix";
+}).overrideAttrs
+  (
+    finalAttrs: prevAttrs: {
+      doCheck = true;
+      doInstallCheck = true;
+
+      checkInputs =
+        [
+          # Make sure the unit tests have passed
+          nix-util-tests.tests.run
+          nix-store-tests.tests.run
+          nix-expr-tests.tests.run
+          nix-fetchers-tests.tests.run
+          nix-flake-tests.tests.run
+
+          # Make sure the functional tests have passed
+          nix-functional-tests
+        ]
+        ++ lib.optionals
+          (!stdenv.hostPlatform.isStatic && stdenv.buildPlatform.canExecute stdenv.hostPlatform)
+          [
+            # Perl currently fails in static build
+            # TODO: Split out tests into a separate derivation?
+            nix-perl-bindings
+          ];
+      passthru = prevAttrs.passthru // {
+        inherit (nix-cli) version;
+
+        /**
+          These are the libraries that are part of the Nix project. They are used
+          by the Nix CLI and other tools.
+
+          If you need to use these libraries in your project, we recommend to use
+          the `-c` C API libraries exclusively, if possible.
+
+          We also recommend that you build the complete package to ensure that the unit tests pass.
+          You could do this in CI, or by passing it in an unused environment variable. e.g in a `mkDerivation` call:
+
+          ```nix
+            buildInputs = [ nix.libs.nix-util-c nix.libs.nix-store-c ];
+            # Make sure the nix libs we use are ok
+            unusedInputsForTests = [ nix ];
+            disallowedReferences = nix.all;
+          ```
+        */
+        inherit libs;
+
+        tests = prevAttrs.passthru.tests or { } // {
+          pkg-config = testers.hasPkgConfigModules {
+            package = finalAttrs.finalPackage;
+          };
+        };
+
+        /**
+          A derivation referencing the `dev` outputs of the Nix libraries.
+        */
+        dev = dev finalAttrs;
+        inherit devdoc;
+        doc = nix-manual;
+        outputs = [
+          "out"
+          "dev"
+          "devdoc"
+          "doc"
+        ];
+        all = lib.attrValues (
+          lib.genAttrs finalAttrs.passthru.outputs (outName: finalAttrs.finalPackage.${outName})
+        );
+      };
+      meta = prevAttrs.meta // {
+        description = "The Nix package manager";
+        pkgConfigModules = (dev finalAttrs).meta.pkgConfigModules;
+      };
+    }
+  )
diff --git a/pkgs/tools/package-management/nix/2_26/source.json b/pkgs/tools/package-management/nix/2_26/source.json
new file mode 100644
index 0000000000000..09afd9c0640ff
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/source.json
@@ -0,0 +1,6 @@
+{
+    "owner": "NixOS",
+    "repo": "nix",
+    "rev": "36bd92736faaf81c6af3dff8f560963eb4e76b14",
+    "hash": "sha256-1T7WRNfUMsiiNB77BuHElzjavguL8oJx+wBtfMcobq8="
+}
diff --git a/pkgs/tools/package-management/nix/2_26/src/external-api-docs/package.nix b/pkgs/tools/package-management/nix/2_26/src/external-api-docs/package.nix
new file mode 100644
index 0000000000000..b194e16d4608a
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/external-api-docs/package.nix
@@ -0,0 +1,56 @@
+{
+  lib,
+  mkMesonDerivation,
+
+  doxygen,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonDerivation (finalAttrs: {
+  pname = "nix-external-api-docs";
+  inherit version;
+
+  workDir = ./.;
+  fileset =
+    let
+      cpp = fileset.fileFilter (file: file.hasExt "cc" || file.hasExt "h");
+    in
+    fileset.unions [
+      ./.version
+      ../../.version
+      ./meson.build
+      ./doxygen.cfg.in
+      ./README.md
+      # Source is not compiled, but still must be available for Doxygen
+      # to gather comments.
+      (cpp ../libexpr-c)
+      (cpp ../libflake-c)
+      (cpp ../libstore-c)
+      (cpp ../libutil-c)
+    ];
+
+  nativeBuildInputs = [
+    doxygen
+  ];
+
+  preConfigure = ''
+    chmod u+w ./.version
+    echo ${finalAttrs.version} > ./.version
+  '';
+
+  postInstall = ''
+    mkdir -p ''${!outputDoc}/nix-support
+    echo "doc external-api-docs $out/share/doc/nix/external-api/html" >> ''${!outputDoc}/nix-support/hydra-build-products
+  '';
+
+  meta = {
+    platforms = lib.platforms.all;
+  };
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/internal-api-docs/package.nix b/pkgs/tools/package-management/nix/2_26/src/internal-api-docs/package.nix
new file mode 100644
index 0000000000000..6c4f354aee5c9
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/internal-api-docs/package.nix
@@ -0,0 +1,52 @@
+{
+  lib,
+  mkMesonDerivation,
+
+  doxygen,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonDerivation (finalAttrs: {
+  pname = "nix-internal-api-docs";
+  inherit version;
+
+  workDir = ./.;
+  fileset =
+    let
+      cpp = fileset.fileFilter (file: file.hasExt "cc" || file.hasExt "hh");
+    in
+    fileset.unions [
+      ./.version
+      ../../.version
+      ./meson.build
+      ./doxygen.cfg.in
+      # Source is not compiled, but still must be available for Doxygen
+      # to gather comments.
+      (cpp ../.)
+    ];
+
+  nativeBuildInputs = [
+    doxygen
+  ];
+
+  preConfigure = ''
+    chmod u+w ./.version
+    echo ${finalAttrs.version} > ./.version
+  '';
+
+  postInstall = ''
+    mkdir -p ''${!outputDoc}/nix-support
+    echo "doc internal-api-docs $out/share/doc/nix/internal-api/html" >> ''${!outputDoc}/nix-support/hydra-build-products
+  '';
+
+  meta = {
+    platforms = lib.platforms.all;
+  };
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libcmd/package.nix b/pkgs/tools/package-management/nix/2_26/src/libcmd/package.nix
new file mode 100644
index 0000000000000..d155d9f1e620d
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libcmd/package.nix
@@ -0,0 +1,84 @@
+{
+  lib,
+  stdenv,
+  mkMesonLibrary,
+
+  nix-util,
+  nix-store,
+  nix-fetchers,
+  nix-expr,
+  nix-flake,
+  nix-main,
+  editline,
+  readline,
+  lowdown,
+  nlohmann_json,
+
+  # Configuration Options
+
+  version,
+
+  # Whether to enable Markdown rendering in the Nix binary.
+  enableMarkdown ? !stdenv.hostPlatform.isWindows,
+
+  # Which interactive line editor library to use for Nix's repl.
+  #
+  # Currently supported choices are:
+  #
+  # - editline (default)
+  # - readline
+  readlineFlavor ? if stdenv.hostPlatform.isWindows then "readline" else "editline",
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-cmd";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    ({ inherit editline readline; }.${readlineFlavor})
+  ] ++ lib.optional enableMarkdown lowdown;
+
+  propagatedBuildInputs = [
+    nix-util
+    nix-store
+    nix-fetchers
+    nix-expr
+    nix-flake
+    nix-main
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+    (lib.mesonEnable "markdown" enableMarkdown)
+    (lib.mesonOption "readline-flavor" readlineFlavor)
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libexpr-c/package.nix b/pkgs/tools/package-management/nix/2_26/src/libexpr-c/package.nix
new file mode 100644
index 0000000000000..ad1ea371c2d7c
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libexpr-c/package.nix
@@ -0,0 +1,54 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-store-c,
+  nix-expr,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-expr-c";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "h") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-store-c
+    nix-expr
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libexpr-test-support/package.nix b/pkgs/tools/package-management/nix/2_26/src/libexpr-test-support/package.nix
new file mode 100644
index 0000000000000..5628d606a4524
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libexpr-test-support/package.nix
@@ -0,0 +1,58 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-store-test-support,
+  nix-expr,
+  nix-expr-c,
+
+  rapidcheck,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-util-test-support";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-store-test-support
+    nix-expr
+    nix-expr-c
+    rapidcheck
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libexpr-tests/package.nix b/pkgs/tools/package-management/nix/2_26/src/libexpr-tests/package.nix
new file mode 100644
index 0000000000000..bb5acb7c873da
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libexpr-tests/package.nix
@@ -0,0 +1,86 @@
+{
+  lib,
+  buildPackages,
+  stdenv,
+  mkMesonExecutable,
+
+  nix-expr,
+  nix-expr-c,
+  nix-expr-test-support,
+
+  rapidcheck,
+  gtest,
+  runCommand,
+
+  # Configuration Options
+
+  version,
+  resolvePath,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-expr-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-expr
+    nix-expr-c
+    nix-expr-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  passthru = {
+    tests = {
+      run =
+        runCommand "${finalAttrs.pname}-run"
+          {
+            meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+          }
+          (
+            lib.optionalString stdenv.hostPlatform.isWindows ''
+              export HOME="$PWD/home-dir"
+              mkdir -p "$HOME"
+            ''
+            + ''
+              export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+              ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+              touch $out
+            ''
+          );
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libexpr/package.nix b/pkgs/tools/package-management/nix/2_26/src/libexpr/package.nix
new file mode 100644
index 0000000000000..afd01c3846e94
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libexpr/package.nix
@@ -0,0 +1,103 @@
+{
+  lib,
+  stdenv,
+  mkMesonLibrary,
+
+  bison,
+  flex,
+  cmake, # for resolving toml11 dep
+
+  nix-util,
+  nix-store,
+  nix-fetchers,
+  boost,
+  boehmgc,
+  nlohmann_json,
+  toml11,
+
+  # Configuration Options
+
+  version,
+
+  # Whether to use garbage collection for the Nix language evaluator.
+  #
+  # If it is disabled, we just leak memory, but this is not as bad as it
+  # sounds so long as evaluation just takes places within short-lived
+  # processes. (When the process exits, the memory is reclaimed; it is
+  # only leaked *within* the process.)
+  #
+  # Temporarily disabled on Windows because the `GC_throw_bad_alloc`
+  # symbol is missing during linking.
+  enableGC ? !stdenv.hostPlatform.isWindows,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-expr";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    ./meson.options
+    ./primops/meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    ./lexer.l
+    ./parser.y
+    (fileset.difference (fileset.fileFilter (file: file.hasExt "nix") ./.) ./package.nix)
+  ];
+
+  nativeBuildInputs = [
+    bison
+    flex
+    cmake
+  ];
+
+  buildInputs = [
+    toml11
+  ];
+
+  propagatedBuildInputs = [
+    nix-util
+    nix-store
+    nix-fetchers
+  ] ++ finalAttrs.passthru.externalPropagatedBuildInputs;
+
+  # Hack for sake of the dev shell
+  passthru.externalPropagatedBuildInputs = [
+    boost
+    nlohmann_json
+  ] ++ lib.optional enableGC boehmgc;
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+    (lib.mesonEnable "gc" enableGC)
+  ];
+
+  env = {
+    # Needed for Meson to find Boost.
+    # https://github.com/NixOS/nixpkgs/issues/86131.
+    BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
+    BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libfetchers-tests/package.nix b/pkgs/tools/package-management/nix/2_26/src/libfetchers-tests/package.nix
new file mode 100644
index 0000000000000..f2680e9b3c1f7
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libfetchers-tests/package.nix
@@ -0,0 +1,84 @@
+{
+  lib,
+  buildPackages,
+  stdenv,
+  mkMesonExecutable,
+
+  nix-fetchers,
+  nix-store-test-support,
+
+  rapidcheck,
+  gtest,
+  runCommand,
+
+  # Configuration Options
+
+  version,
+  resolvePath,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-fetchers-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-fetchers
+    nix-store-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  passthru = {
+    tests = {
+      run =
+        runCommand "${finalAttrs.pname}-run"
+          {
+            meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+          }
+          (
+            lib.optionalString stdenv.hostPlatform.isWindows ''
+              export HOME="$PWD/home-dir"
+              mkdir -p "$HOME"
+            ''
+            + ''
+              export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+              ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+              touch $out
+            ''
+          );
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libfetchers/package.nix b/pkgs/tools/package-management/nix/2_26/src/libfetchers/package.nix
new file mode 100644
index 0000000000000..b0aecd04979e2
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libfetchers/package.nix
@@ -0,0 +1,56 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util,
+  nix-store,
+  nlohmann_json,
+  libgit2,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-fetchers";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    libgit2
+  ];
+
+  propagatedBuildInputs = [
+    nix-store
+    nix-util
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libflake-c/package.nix b/pkgs/tools/package-management/nix/2_26/src/libflake-c/package.nix
new file mode 100644
index 0000000000000..f0615a42798ee
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libflake-c/package.nix
@@ -0,0 +1,56 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-store-c,
+  nix-expr-c,
+  nix-flake,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-flake-c";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "h") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-expr-c
+    nix-store-c
+    nix-flake
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libflake-tests/package.nix b/pkgs/tools/package-management/nix/2_26/src/libflake-tests/package.nix
new file mode 100644
index 0000000000000..f9d9b0bc0c6bd
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libflake-tests/package.nix
@@ -0,0 +1,87 @@
+{
+  lib,
+  buildPackages,
+  stdenv,
+  mkMesonExecutable,
+
+  nix-flake,
+  nix-flake-c,
+  nix-expr-test-support,
+
+  rapidcheck,
+  gtest,
+  runCommand,
+
+  # Configuration Options
+
+  version,
+  resolvePath,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-flake-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-flake
+    nix-flake-c
+    nix-expr-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  passthru = {
+    tests = {
+      run =
+        runCommand "${finalAttrs.pname}-run"
+          {
+            meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+          }
+          (
+            lib.optionalString stdenv.hostPlatform.isWindows ''
+              export HOME="$PWD/home-dir"
+              mkdir -p "$HOME"
+            ''
+            + ''
+              export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+              export NIX_CONFIG="extra-experimental-features = flakes"
+              ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+              touch $out
+            ''
+          );
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libflake/package.nix b/pkgs/tools/package-management/nix/2_26/src/libflake/package.nix
new file mode 100644
index 0000000000000..ebd38e140d302
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libflake/package.nix
@@ -0,0 +1,55 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util,
+  nix-store,
+  nix-fetchers,
+  nix-expr,
+  nlohmann_json,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-flake";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-store
+    nix-util
+    nix-fetchers
+    nix-expr
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libmain-c/package.nix b/pkgs/tools/package-management/nix/2_26/src/libmain-c/package.nix
new file mode 100644
index 0000000000000..cf710e03b0d07
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libmain-c/package.nix
@@ -0,0 +1,58 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util-c,
+  nix-store,
+  nix-store-c,
+  nix-main,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-main-c";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "h") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util-c
+    nix-store
+    nix-store-c
+    nix-main
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libmain/package.nix b/pkgs/tools/package-management/nix/2_26/src/libmain/package.nix
new file mode 100644
index 0000000000000..046b505dfd46d
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libmain/package.nix
@@ -0,0 +1,52 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  openssl,
+
+  nix-util,
+  nix-store,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-main";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util
+    nix-store
+    openssl
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libstore-c/package.nix b/pkgs/tools/package-management/nix/2_26/src/libstore-c/package.nix
new file mode 100644
index 0000000000000..89abeaab87063
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libstore-c/package.nix
@@ -0,0 +1,54 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util-c,
+  nix-store,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-store-c";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "h") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util-c
+    nix-store
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libstore-test-support/package.nix b/pkgs/tools/package-management/nix/2_26/src/libstore-test-support/package.nix
new file mode 100644
index 0000000000000..7cc29795c1903
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libstore-test-support/package.nix
@@ -0,0 +1,58 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util-test-support,
+  nix-store,
+  nix-store-c,
+
+  rapidcheck,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-store-test-support";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util-test-support
+    nix-store
+    nix-store-c
+    rapidcheck
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libstore-tests/package.nix b/pkgs/tools/package-management/nix/2_26/src/libstore-tests/package.nix
new file mode 100644
index 0000000000000..670386c4a6ff3
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libstore-tests/package.nix
@@ -0,0 +1,103 @@
+{
+  lib,
+  buildPackages,
+  stdenv,
+  mkMesonExecutable,
+
+  nix-store,
+  nix-store-c,
+  nix-store-test-support,
+  sqlite,
+
+  rapidcheck,
+  gtest,
+  runCommand,
+
+  # Configuration Options
+
+  version,
+  filesetToSource,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-store-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  # Hack for sake of the dev shell
+  passthru.externalBuildInputs = [
+    sqlite
+    rapidcheck
+    gtest
+  ];
+
+  buildInputs = finalAttrs.passthru.externalBuildInputs ++ [
+    nix-store
+    nix-store-c
+    nix-store-test-support
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  passthru = {
+    tests = {
+      run =
+        let
+          # Some data is shared with the functional tests: they create it,
+          # we consume it.
+          data = filesetToSource {
+            root = ../..;
+            fileset = lib.fileset.unions [
+              ./data
+              ../../tests/functional/derivation
+            ];
+          };
+        in
+        runCommand "${finalAttrs.pname}-run"
+          {
+            meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+          }
+          (
+            lib.optionalString stdenv.hostPlatform.isWindows ''
+              export HOME="$PWD/home-dir"
+              mkdir -p "$HOME"
+            ''
+            + ''
+              export _NIX_TEST_UNIT_DATA=${data + "/src/libstore-tests/data"}
+              ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+              touch $out
+            ''
+          );
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libstore/package.nix b/pkgs/tools/package-management/nix/2_26/src/libstore/package.nix
new file mode 100644
index 0000000000000..c982b44f0b738
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libstore/package.nix
@@ -0,0 +1,100 @@
+{
+  lib,
+  stdenv,
+  mkMesonLibrary,
+
+  unixtools,
+  darwin,
+
+  nix-util,
+  boost,
+  curl,
+  aws-sdk-cpp,
+  libseccomp,
+  nlohmann_json,
+  sqlite,
+
+  busybox-sandbox-shell ? null,
+
+  # Configuration Options
+
+  version,
+
+  embeddedSandboxShell ? stdenv.hostPlatform.isStatic,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-store";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    ./meson.options
+    ./linux/meson.build
+    ./unix/meson.build
+    ./windows/meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "sb") ./.)
+    (fileset.fileFilter (file: file.hasExt "md") ./.)
+    (fileset.fileFilter (file: file.hasExt "sql") ./.)
+  ];
+
+  nativeBuildInputs = lib.optional embeddedSandboxShell unixtools.hexdump;
+
+  buildInputs =
+    [
+      boost
+      curl
+      sqlite
+    ]
+    ++ lib.optional stdenv.hostPlatform.isLinux libseccomp
+    # There have been issues building these dependencies
+    ++ lib.optional stdenv.hostPlatform.isDarwin darwin.apple_sdk.libs.sandbox
+    ++ lib.optional (
+      stdenv.hostPlatform == stdenv.buildPlatform && (stdenv.isLinux || stdenv.isDarwin)
+    ) aws-sdk-cpp;
+
+  propagatedBuildInputs = [
+    nix-util
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags =
+    [
+      (lib.mesonEnable "seccomp-sandboxing" stdenv.hostPlatform.isLinux)
+      (lib.mesonBool "embedded-sandbox-shell" embeddedSandboxShell)
+    ]
+    ++ lib.optionals stdenv.hostPlatform.isLinux [
+      (lib.mesonOption "sandbox-shell" "${busybox-sandbox-shell}/bin/busybox")
+    ];
+
+  env = {
+    # Needed for Meson to find Boost.
+    # https://github.com/NixOS/nixpkgs/issues/86131.
+    BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
+    BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libutil-c/package.nix b/pkgs/tools/package-management/nix/2_26/src/libutil-c/package.nix
new file mode 100644
index 0000000000000..72f57d6f9c62e
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libutil-c/package.nix
@@ -0,0 +1,52 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-util-c";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+    (fileset.fileFilter (file: file.hasExt "h") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libutil-test-support/package.nix b/pkgs/tools/package-management/nix/2_26/src/libutil-test-support/package.nix
new file mode 100644
index 0000000000000..33cd5217defaf
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libutil-test-support/package.nix
@@ -0,0 +1,56 @@
+{
+  lib,
+  mkMesonLibrary,
+
+  nix-util,
+  nix-util-c,
+
+  rapidcheck,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-util-test-support";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util
+    nix-util-c
+    rapidcheck
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libutil-tests/package.nix b/pkgs/tools/package-management/nix/2_26/src/libutil-tests/package.nix
new file mode 100644
index 0000000000000..d4eea3a8dc260
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libutil-tests/package.nix
@@ -0,0 +1,86 @@
+{
+  lib,
+  buildPackages,
+  stdenv,
+  mkMesonExecutable,
+
+  nix-util,
+  nix-util-c,
+  nix-util-test-support,
+
+  rapidcheck,
+  gtest,
+  runCommand,
+
+  # Configuration Options
+
+  version,
+  resolvePath,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-util-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-util
+    nix-util-c
+    nix-util-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  passthru = {
+    tests = {
+      run =
+        runCommand "${finalAttrs.pname}-run"
+          {
+            meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+          }
+          (
+            lib.optionalString stdenv.hostPlatform.isWindows ''
+              export HOME="$PWD/home-dir"
+              mkdir -p "$HOME"
+            ''
+            + ''
+              export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+              ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+              touch $out
+            ''
+          );
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/libutil/package.nix b/pkgs/tools/package-management/nix/2_26/src/libutil/package.nix
new file mode 100644
index 0000000000000..586119a6e5d5e
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/libutil/package.nix
@@ -0,0 +1,81 @@
+{
+  lib,
+  stdenv,
+  mkMesonLibrary,
+
+  boost,
+  brotli,
+  libarchive,
+  libcpuid,
+  libsodium,
+  nlohmann_json,
+  openssl,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-util";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../nix-meson-build-support
+    ./nix-meson-build-support
+    ../../.version
+    ./.version
+    ./widecharwidth
+    ./meson.build
+    ./meson.options
+    ./linux/meson.build
+    ./unix/meson.build
+    ./windows/meson.build
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    brotli
+    libsodium
+    openssl
+  ] ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid;
+
+  propagatedBuildInputs = [
+    boost
+    libarchive
+    nlohmann_json
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    #
+    # TODO: change release process to add `pre` in `.version`, remove it
+    # before tagging, and restore after.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+    (lib.mesonEnable "cpuid" stdenv.hostPlatform.isx86_64)
+  ];
+
+  env = {
+    # Needed for Meson to find Boost.
+    # https://github.com/NixOS/nixpkgs/issues/86131.
+    BOOST_INCLUDEDIR = "${lib.getDev boost}/include";
+    BOOST_LIBRARYDIR = "${lib.getLib boost}/lib";
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/nix/package.nix b/pkgs/tools/package-management/nix/2_26/src/nix/package.nix
new file mode 100644
index 0000000000000..89c52c3bb0506
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/nix/package.nix
@@ -0,0 +1,109 @@
+{
+  lib,
+  mkMesonExecutable,
+
+  nix-store,
+  nix-expr,
+  nix-main,
+  nix-cmd,
+
+  # Configuration Options
+
+  version,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions (
+    [
+      ../../nix-meson-build-support
+      ./nix-meson-build-support
+      ../../.version
+      ./.version
+      ./meson.build
+      ./meson.options
+
+      # Symbolic links to other dirs
+      ## exes
+      ./build-remote
+      ./doc
+      ./nix-build
+      ./nix-channel
+      ./nix-collect-garbage
+      ./nix-copy-closure
+      ./nix-env
+      ./nix-instantiate
+      ./nix-store
+      ## dirs
+      ./scripts
+      ../../scripts
+      ./misc
+      ../../misc
+
+      # Doc nix files for --help
+      ../../doc/manual/generate-manpage.nix
+      ../../doc/manual/utils.nix
+      ../../doc/manual/generate-settings.nix
+      ../../doc/manual/generate-store-info.nix
+
+      # Other files to be included as string literals
+      ../nix-channel/unpack-channel.nix
+      ../nix-env/buildenv.nix
+      ./get-env.sh
+      ./help-stores.md
+      ../../doc/manual/source/store/types/index.md.in
+      ./profiles.md
+      ../../doc/manual/source/command-ref/files/profiles.md
+
+      # Files
+    ]
+    ++
+      lib.concatMap
+        (dir: [
+          (fileset.fileFilter (file: file.hasExt "cc") dir)
+          (fileset.fileFilter (file: file.hasExt "hh") dir)
+          (fileset.fileFilter (file: file.hasExt "md") dir)
+        ])
+        [
+          ./.
+          ../build-remote
+          ../nix-build
+          ../nix-channel
+          ../nix-collect-garbage
+          ../nix-copy-closure
+          ../nix-env
+          ../nix-instantiate
+          ../nix-store
+        ]
+  );
+
+  buildInputs = [
+    nix-store
+    nix-expr
+    nix-main
+    nix-cmd
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/pkgs/tools/package-management/nix/2_26/src/perl/package.nix b/pkgs/tools/package-management/nix/2_26/src/perl/package.nix
new file mode 100644
index 0000000000000..d95d13aa92133
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/src/perl/package.nix
@@ -0,0 +1,82 @@
+{
+  lib,
+  stdenv,
+  mkMesonDerivation,
+  pkg-config,
+  perl,
+  perlPackages,
+  nix-store,
+  version,
+  curl,
+  bzip2,
+  libsodium,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+perl.pkgs.toPerlModule (
+  mkMesonDerivation (finalAttrs: {
+    pname = "nix-perl";
+    inherit version;
+
+    workDir = ./.;
+    fileset = fileset.unions (
+      [
+        ./.version
+        ../../.version
+        ./MANIFEST
+        ./lib
+        ./meson.build
+        ./meson.options
+      ]
+      ++ lib.optionals finalAttrs.doCheck [
+        ./.yath.rc.in
+        ./t
+      ]
+    );
+
+    nativeBuildInputs = [
+      pkg-config
+      perl
+      curl
+    ];
+
+    buildInputs = [
+      nix-store
+    ] ++ finalAttrs.passthru.externalBuildInputs;
+
+    # Hack for sake of the dev shell
+    passthru.externalBuildInputs = [
+      bzip2
+      libsodium
+    ];
+
+    # `perlPackages.Test2Harness` is marked broken for Darwin
+    doCheck = !stdenv.isDarwin;
+
+    nativeCheckInputs = [
+      perlPackages.Test2Harness
+    ];
+
+    preConfigure =
+      # "Inline" .version so its not a symlink, and includes the suffix
+      ''
+        chmod u+w .version
+        echo ${finalAttrs.version} > .version
+      '';
+
+    mesonFlags = [
+      (lib.mesonOption "dbi_path" "${perlPackages.DBI}/${perl.libPrefix}")
+      (lib.mesonOption "dbd_sqlite_path" "${perlPackages.DBDSQLite}/${perl.libPrefix}")
+      (lib.mesonEnable "tests" finalAttrs.doCheck)
+    ];
+
+    mesonCheckFlags = [
+      "--print-errorlogs"
+    ];
+
+    strictDeps = false;
+  })
+)
diff --git a/pkgs/tools/package-management/nix/2_26/tests/functional/package.nix b/pkgs/tools/package-management/nix/2_26/tests/functional/package.nix
new file mode 100644
index 0000000000000..74c034196fde7
--- /dev/null
+++ b/pkgs/tools/package-management/nix/2_26/tests/functional/package.nix
@@ -0,0 +1,110 @@
+{
+  lib,
+  stdenv,
+  mkMesonDerivation,
+
+  meson,
+  ninja,
+  pkg-config,
+
+  jq,
+  git,
+  mercurial,
+  util-linux,
+
+  nix-store,
+  nix-expr,
+  nix-cli,
+
+  busybox-sandbox-shell ? null,
+
+  # Configuration Options
+
+  pname ? "nix-functional-tests",
+  version,
+
+  # For running the functional tests against a different pre-built Nix.
+  test-daemon ? null,
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonDerivation (
+  finalAttrs:
+  {
+    inherit pname version;
+
+    workDir = ./.;
+    fileset = fileset.unions [
+      ../../scripts/nix-profile.sh.in
+      ../../.version
+      ../../tests/functional
+      ./.
+    ];
+
+    # Hack for sake of the dev shell
+    passthru.externalNativeBuildInputs =
+      [
+        meson
+        ninja
+        pkg-config
+
+        jq
+        git
+        mercurial
+      ]
+      ++ lib.optionals stdenv.hostPlatform.isLinux [
+        # For various sandboxing tests that needs a statically-linked shell,
+        # etc.
+        busybox-sandbox-shell
+        # For Overlay FS tests need `mount`, `umount`, and `unshare`.
+        # For `script` command (ensuring a TTY)
+        # TODO use `unixtools` to be precise over which executables instead?
+        util-linux
+      ];
+
+    nativeBuildInputs = finalAttrs.passthru.externalNativeBuildInputs ++ [
+      nix-cli
+    ];
+
+    buildInputs = [
+      nix-store
+      nix-expr
+    ];
+
+    preConfigure =
+      # "Inline" .version so it's not a symlink, and includes the suffix.
+      # Do the meson utils, without modification.
+      ''
+        chmod u+w ./.version
+        echo ${version} > ../../../.version
+      ''
+      # TEMP hack for Meson before make is gone, where
+      # `src/nix-functional-tests` is during the transition a symlink and
+      # not the actual directory directory.
+      + ''
+        cd $(readlink -e $PWD)
+        echo $PWD | grep tests/functional
+      '';
+
+    mesonCheckFlags = [
+      "--print-errorlogs"
+    ];
+
+    doCheck = true;
+
+    installPhase = ''
+      mkdir $out
+    '';
+
+    meta = {
+      platforms = lib.platforms.unix;
+    };
+
+  }
+  // lib.optionalAttrs (test-daemon != null) {
+    NIX_DAEMON_PACKAGE = test-daemon;
+  }
+)
diff --git a/pkgs/tools/package-management/nix/common.nix b/pkgs/tools/package-management/nix/common.nix
index 9732b8a98c049..bfecf16919dc0 100644
--- a/pkgs/tools/package-management/nix/common.nix
+++ b/pkgs/tools/package-management/nix/common.nix
@@ -250,37 +250,9 @@ self = stdenv.mkDerivation {
 
     perl-bindings = perl.pkgs.toPerlModule (callPackage ./nix-perl.nix { nix = self; inherit Security; });
 
-    tests = {
-      srcVersion = runCommand "nix-src-version" {
-        inherit version;
-      } ''
-        # This file is an implementation detail, but it's a good sanity check
-        # If upstream changes that, we'll have to adapt.
-        srcVersion=$(cat ${src}/.version)
-        echo "Version in nix nix expression: $version"
-        echo "Version in nix.src: $srcVersion"
-        if [ "$version" != "$srcVersion" ]; then
-          echo "Version mismatch!"
-          exit 1
-        fi
-        touch $out
-      '';
-
-      /** Intended to test `lib`, but also a good smoke test for Nix */
-      nixpkgs-lib = import ../../../../lib/tests/test-with-nix.nix {
-        inherit lib pkgs;
-        nix = self;
-      };
-    } // lib.optionalAttrs stdenv.hostPlatform.isLinux {
-      nixStatic = pkgsStatic.nixVersions.${self_attribute_name};
-
-      # Basic smoke tests that needs to pass when upgrading nix.
-      # Note that this test does only test the nixVersions.stable attribute.
-      misc = nixosTests.nix-misc.default;
-      upgrade = nixosTests.nix-upgrade;
-      simpleUefiSystemdBoot = nixosTests.installer.simpleUefiSystemdBoot;
-    } // lib.optionalAttrs (stdenv.hostPlatform.system == "x86_64-linux") {
-      nixi686 = pkgsi686Linux.nixVersions.${self_attribute_name};
+    tests = import ./tests.nix {
+      inherit runCommand version src lib stdenv pkgs pkgsi686Linux pkgsStatic nixosTests self_attribute_name;
+      nix = self;
     };
   };
 
diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index 548adcb8d7a7d..23b11f1c62857 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -9,6 +9,10 @@
 , fetchpatch2
 , runCommand
 , Security
+, pkgs
+, pkgsi686Linux
+, pkgsStatic
+, nixosTests
 
 , storeDir ? "/nix/store"
 , stateDir ? "/nix/var"
@@ -160,6 +164,19 @@ in lib.makeExtensible (self: ({
     self_attribute_name = "nix_2_25";
   };
 
+  nix_2_26 = (callPackage ./2_26/componentized.nix { }).overrideAttrs (this: old: {
+    passthru = old.passthru or {} // {
+      tests =
+        old.passthru.tests or {}
+        // import ./tests.nix {
+          inherit runCommand lib stdenv pkgs pkgsi686Linux pkgsStatic nixosTests;
+          inherit (old) version src;
+          nix = this.finalPackage;
+          self_attribute_name = "nix_2_26";
+        };
+    };
+  });
+
   git = common rec {
     version = "2.25.0";
     suffix = "pre20241101_${lib.substring 0 8 src.rev}";
diff --git a/pkgs/tools/package-management/nix/tests.nix b/pkgs/tools/package-management/nix/tests.nix
new file mode 100644
index 0000000000000..662cfe7d194cd
--- /dev/null
+++ b/pkgs/tools/package-management/nix/tests.nix
@@ -0,0 +1,52 @@
+{
+  runCommand,
+  version,
+  src,
+  nix,
+  lib,
+  stdenv,
+  pkgs,
+  pkgsi686Linux,
+  pkgsStatic,
+  nixosTests,
+  self_attribute_name,
+}:
+{
+  srcVersion =
+    runCommand "nix-src-version"
+      {
+        inherit version;
+      }
+      ''
+        # This file is an implementation detail, but it's a good sanity check
+        # If upstream changes that, we'll have to adapt.
+        srcVersion=$(cat ${src}/.version)
+        echo "Version in nix nix expression: $version"
+        echo "Version in nix.src: $srcVersion"
+        if [ "$version" != "$srcVersion" ]; then
+          echo "Version mismatch!"
+          exit 1
+        fi
+        touch $out
+      '';
+
+  /**
+    Intended to test `lib`, but also a good smoke test for Nix
+  */
+  nixpkgs-lib = import ../../../../lib/tests/test-with-nix.nix {
+    inherit lib pkgs;
+    inherit nix;
+  };
+}
+// lib.optionalAttrs stdenv.hostPlatform.isLinux {
+  nixStatic = pkgsStatic.nixVersions.${self_attribute_name};
+
+  # Basic smoke tests that needs to pass when upgrading nix.
+  # Note that this test does only test the nixVersions.stable attribute.
+  misc = nixosTests.nix-misc.default;
+  upgrade = nixosTests.nix-upgrade;
+  simpleUefiSystemdBoot = nixosTests.installer.simpleUefiSystemdBoot;
+}
+// lib.optionalAttrs (stdenv.hostPlatform.system == "x86_64-linux") {
+  nixi686 = pkgsi686Linux.nixVersions.${self_attribute_name};
+}