Allow use of lix from nixpkgs

Change behaviour of module. Allow not specifying LixSrc
and provide fallback to nixpkgs.pkgs.lix

README.md

@@ -1,79 +1,5 @@
 # Lix NixOS module
 
-See the [official installation guide][install-guide] for details on usage of
+See the [beta guide][beta-guide] for details on how to use this:
-release versions.
-
-[install-guide]: https://lix.systems/install/
-
-See the [beta guide][beta-guide] for a setup guide on how to use HEAD:
 
 [beta-guide]: https://wiki.lix.systems/link/1
-
-## What does this do?
-
-This is an overlay wrapped in a NixOS module that will replace CppNix with Lix
-in nixpkgs. This is useful so that `nixos-rebuild`, `nix-direnv` and similar
-will use Lix.
-
-Optionally, it can build Lix from source.
-
-## Versioning with Lix
-
-The version of this overlay should match the major Lix version, *and* if
-running HEAD, it should be the latest available version of the overlay.
-Changes breaking the overlay are shamelessly done on HEAD, and we expect people
-doing such changes to have prepared corresponding fix commits to make to the
-overlay immediately after submitting their changes. If your build randomly
-broke when updating HEAD, try updating your overlay.
-
-The version of Lix pinned in this flake's `flake.lock` is a version of Lix
-that is expected to work, however if running HEAD, it can be assumed to work
-with HEAD as well if both `lix-nixos-module` and `lix` are the latest version.
-
-## Common pitfalls
-
-Various flake frameworks such as flake-parts and snowfall (and possibly Colmena
-in the future if they do a similar optimization) manage overlays separately
-from NixOS, since they provide `pkgs` pre-imported to NixOS. This saves a
-couple of seconds of evaluation time and resources, but it means that the NixOS
-option `nixpkgs.overlays` **is completely ignored** on these frameworks.
-
-If you are using such a framework, add `overlays.default` to the overlays list
-for said framework.
-
-## Flake structure and usage
-
-The flake here has two inputs of note:
-- `nixpkgs`, *which is unused for most people*. It is purely used for `checks`
-  in developing `lix-nixos-module` itself.
-
-  The installation instructions make it `follows` to make `flake.lock` less
-  confusing, but it is nonetheless unused.
-- `lix`, which determines the version of Lix to do source builds for, if doing
-  source builds.
-
-These are the most relevant outputs for most people:
-
-- `nixosModules.lixFromNixpkgs` - uses Lix from nixpkgs and installs the
-  overlay to use Lix on a NixOS system. This is only useful for a stable
-  version of Lix, and cannot be used for running HEAD.
-- `nixosModules.default` - uses Lix from source and installs the overlay to use
-  Lix on a NixOS system.
-- `overlays.lixFromNixpkgs` - overlay to use Lix from nixpkgs in place of Nix.
-- `overlays.default` - overlay to use Lix from source in place of Nix.
-
-## Non-flake usage
-
-Import `module.nix` or `overlay.nix` as desired, with the arguments `lix`
-(derivation-like attribute set with the Lix sources, or `null` to use Lix from
-nixpkgs) and `versionSuffix` (optional string).
-
-It's desirable to also include a `versionSuffix` like the following while
-building HEAD from source, to have `nix --version` include date and commit
-information. To get such metadata, it depends on which pinning system is in
-use, but `builtins.fetchGit` will provide the necessary metadata for the
-following to work:
-
-```
-versionSuffix = "pre${builtins.substring 0 8 lix.lastModifiedDate}-${lix.shortRev or lix.dirtyShortRev}";
-```

flake.lock

@@ -5,11 +5,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1731533236,
+        "lastModified": 1710146030,
-        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
         "type": "github"
       },
       "original": {
@@ -36,11 +36,11 @@
     "lix": {
       "flake": false,
       "locked": {
-        "lastModified": 1731683711,
+        "lastModified": 1718767907,
-        "narHash": "sha256-bq21I1EjXJa/s5Rra9J9ot2NkPCnI0F5uNPurwYLdpE=",
+        "narHash": "sha256-gpd+mGQxqVHw2kO6rSPQel8TkChHh9UpqxjsmQi0QJM=",
-        "rev": "c859d03013712b349d82ee6223948d6d03e63a8d",
+        "rev": "85f282ef572577899b3d80ba8def1b920a386218",
         "type": "tarball",
-        "url": "https://git.lix.systems/api/v1/repos/lix-project/lix/archive/c859d03013712b349d82ee6223948d6d03e63a8d.tar.gz?rev=c859d03013712b349d82ee6223948d6d03e63a8d"
+        "url": "https://git.lix.systems/api/v1/repos/lix-project/lix/archive/85f282ef572577899b3d80ba8def1b920a386218.tar.gz"
       },
       "original": {
         "type": "tarball",
@@ -49,11 +49,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1731676054,
+        "lastModified": 1718530797,
-        "narHash": "sha256-OZiZ3m8SCMfh3B6bfGC/Bm4x3qc1m2SVEAlkV6iY7Yg=",
+        "narHash": "sha256-pup6cYwtgvzDpvpSCFh1TEUjw2zkNpk8iolbKnyFmmU=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "5e4fbfb6b3de1aa2872b76d49fafc942626e2add",
+        "rev": "b60ebf54c15553b393d144357375ea956f89e9a9",
         "type": "github"
       },
       "original": {

flake.nix

@@ -8,28 +8,11 @@
   inputs.flakey-profile.url = "github:lf-/flakey-profile";
 
   outputs = inputs@{ self, nixpkgs, lix, flake-utils, flakey-profile, ... }:
-    let
+    let versionSuffix = "pre${builtins.substring 0 8 lix.lastModifiedDate}-${lix.shortRev or lix.dirtyShortRev}";
-      lixVersionJson = builtins.fromJSON (builtins.readFile (lix + "/version.json"));
+    in {
-      versionSuffix = nixpkgs.lib.optionalString (!lixVersionJson.official_release)
-        "-pre${builtins.substring 0 8 lix.lastModifiedDate}-${lix.shortRev or lix.dirtyShortRev}";
-    in
-    {
       inherit inputs;
-      nixosModules = {
+      nixosModules.default = import ./module.nix { inherit lix versionSuffix; };
-        # Use a locally built Lix
+      overlays.default = import ./overlay.nix { inherit lix versionSuffix; };
-        default = import ./module.nix { inherit lix versionSuffix; };
-
-        # Use Lix from nixpkgs
-        lixFromNixpkgs = import ./module.nix { lix = null; };
-      };
-
-      overlays = {
-        # Use a locally built Lix
-        default = import ./overlay.nix { inherit lix versionSuffix; };
-
-        # Use Lix from nixpkgs
-        lixFromNixpkgs = import ./overlay.nix { lix = null; };
-      };
     } // flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs {
@@ -47,19 +30,17 @@
       {
         inherit pkgs;
         packages = {
-          default = pkgs.nix;
+          default = pkgs.nixVersions.nix_2_18;
           inherit (pkgs) nix-doc nix-eval-jobs;
         };
 
         packages.system-profile = import ./system-profile.nix { inherit pkgs flakey-profile; };
 
-        nixosTests = pkgs.recurseIntoAttrs (pkgs.callPackage ./test-nixos.nix { inherit pkgs; lix-module = self.nixosModules.default; });
+        nixosTests = pkgs.recurseIntoAttrs (pkgs.callPackage ./test-nixos.nix { lix-module = self.nixosModules.default; });
 
         checks = {
           inherit (self.packages.${system}) default nix-eval-jobs;
-          inherit (pkgs) nixos-option nix-doc;
         } // lib.optionalAttrs (lib.elem system linux64BitSystems) {
-          # wrongMajor intentionally not included here since it is expected to fail
           inherit (self.nixosTests.${system}) it-builds;
         };
       });

module.nix

@@ -1,5 +1,5 @@
-{ lix, versionSuffix ? "" }:
+{ lixSrc ? null, versionSuffix ? "" }:
 { pkgs, config, ... }:
 {
-  nixpkgs.overlays = [ (import ./overlay.nix { inherit lix versionSuffix; }) ];
+  nixpkgs.overlays = [ (import ./overlay.nix { inherit lixSrc versionSuffix; }) ];
 }

nix-doc/package.nix

@@ -0,0 +1,64 @@
+# Temporary replacement of the nix-doc package with
+# https://github.com/NixOS/nixpkgs/pull/296523 so that we can have working Lix
+# with nix-doc on 23.11 and 24.05-pre
+#
+# Can be removed when that commit is in 23.11 and 24.05-pre, or 24.05 is
+# released with the commit.
+{ lib
+, stdenv
+, rustPlatform
+, fetchFromGitHub
+, boost
+, nix
+, pkg-config
+# Whether to build the nix-doc plugin for Nix
+, withPlugin ? true
+}:
+
+let
+  packageFlags = [ "-p" "nix-doc" ] ++ lib.optionals withPlugin [ "-p" "nix-doc-plugin" ];
+in
+rustPlatform.buildRustPackage rec {
+  pname = "nix-doc";
+  version = "0.6.5";
+
+  src = fetchFromGitHub {
+    rev = "v${version}";
+    owner = "lf-";
+    repo = "nix-doc";
+    sha256 = "sha256-9cuNzq+CBA2jz0LkZb7lh/WISIlKklfovGBAbSo1Mgk=";
+  };
+
+  doCheck = true;
+  buildInputs = lib.optionals withPlugin [ boost nix ];
+
+  nativeBuildInputs = lib.optionals withPlugin [ pkg-config nix ];
+
+  cargoBuildFlags = packageFlags;
+  cargoTestFlags = packageFlags;
+
+  # Packaging support for making the nix-doc plugin load cleanly as a no-op on
+  # the wrong Nix version (disabling bindnow permits loading libraries
+  # requiring unavailable symbols if they are unreached)
+  hardeningDisable = lib.optionals withPlugin [ "bindnow" ];
+  # Due to a Rust bug, setting -Z relro-level to anything including "off" on
+  # macOS will cause link errors
+  env = lib.optionalAttrs (withPlugin && stdenv.isLinux) {
+    # nix-doc does not use nightly features, however, there is no other way to
+    # set relro-level
+    RUSTC_BOOTSTRAP = 1;
+    RUSTFLAGS = "-Z relro-level=partial";
+  };
+
+  cargoSha256 = "sha256-CHagzXTG9AfrFd3WmHanQ+YddMgmVxSuB8vK98A1Mlw=";
+
+  meta = with lib; {
+    description = "An interactive Nix documentation tool";
+    longDescription = "An interactive Nix documentation tool providing a CLI for function search, a Nix plugin for docs in the REPL, and a ctags implementation for Nix script";
+    homepage = "https://github.com/lf-/nix-doc";
+    license = licenses.lgpl3Plus;
+    maintainers = [ maintainers.lf- ];
+    platforms = platforms.unix;
+    mainProgram = "nix-doc";
+  };
+}

overlay.nix

@@ -1,14 +1,23 @@
-{ lix, versionSuffix ? "" }:
+{ lixSrc ? null, versionSuffix ? "" }:
 final: prev:
 let
-  lixPackageFromSource = final.callPackage (lix + "/package.nix") ({
+  # This is kind of scary to not override the nix version to pretend to be
-    inherit versionSuffix;
+  # 2.18 since nixpkgs can introduce new breakage in its Nix unstable CLI
-    stdenv = final.clangStdenv;
+  # usage.
+  # https://github.com/nixos/nixpkgs/blob/6afb255d976f85f3359e4929abd6f5149c323a02/nixos/modules/config/nix.nix#L121
+  lixPkg =
+    if lixSrc == null
+    then prev.pkgs.lix
+    else
+      final.callPackage (lixSrc + "/package.nix") ({
+        versionSuffix = "-${versionSuffix}";
+        # FIXME: do this more sensibly for future releases
+        # https://git.lix.systems/lix-project/lix/issues/406
+        officialRelease = false;
       });
 
-  # These packages should receive CppNix since they may link to it or otherwise
+  # These packages depend on Nix features that Lix does not support
-  # cause problems (or even just silly mass-rebuilds) if we give them Lix
+  overridelist_2_18 = [
-  overridelist_upstream = [
     "attic-client"
     "devenv"
     "nix-du"
@@ -18,14 +27,13 @@ let
     "nurl"
     "prefetch-yarn-deps" # force these onto upstream so we are not regularly rebuilding electron
   ];
+  override_2_18 = prev.lib.genAttrs overridelist_2_18 (
+    name: prev.${name}.override {
+      nix = final.nixVersions.nix_2_18_upstream;
+    });
 
-  inherit (prev) lib;
-
-  csi = builtins.fromJSON ''"\u001b"'';
-  orange = "${csi}[35;1m";
-  normal = "${csi}[0m";
   warning = ''
-    ${orange}warning${normal}: You have the lix overlay included into a nixpkgs import twice,
+    warning: You have the lix overlay included into a nixpkgs import twice,
     perhaps due to the NixOS module being included twice, or because of using
     pkgs.nixos and also including it in imports, or perhaps some unknown
     machinations of a complicated flake library.
@@ -38,76 +46,30 @@ let
     delete that.
     P.P.S. This Lix has super catgirl powers.
   '';
-  wrongMajorWarning = ''
-    ${orange}warning${normal}: This Lix NixOS module is being built against a Lix with a
-    major version (got ${lixPackageToUse.version}) other than the one the
-    module was designed for (expecting ${supportedLixMajor}). Some downstream
-    packages like nix-eval-jobs may be broken by this. Consider using a
-    matching version of the Lix NixOS module to the version of Lix you are
-    using.
-  '';
 
   maybeWarnDuplicate = x: if final.lix-overlay-present > 1 then builtins.trace warning x else x;
 
-  versionJson = builtins.fromJSON (builtins.readFile ./version.json);
+  overlay = override_2_18 // {
-  supportedLixMajor = lib.versions.majorMinor versionJson.version;
-  lixPackageToUse = if lix != null then lixPackageFromSource else prev.lix;
-  # Especially if using Lix from nixpkgs, it is plausible that the overlay
-  # could be used against the wrong Lix major version and cause confusing build
-  # errors. This is a simple safeguard to put in at least something that might be seen.
-  maybeWarnWrongMajor = x: if !(lib.hasPrefix supportedLixMajor lixPackageToUse.version) then builtins.trace wrongMajorWarning x else x;
-
-  # It is not enough to *just* throw whatever the default nix version is at
-  # anything in the "don't give lix" list, we have to *also* ensure that we
-  # give whatever upstream version as specified in the callPackage invocation.
-  #
-  # Unfortunately I don't think there is any actual way to directly query that,
-  # so we instead do something extremely evil and guess which version it
-  # probably was. This code is not generalizable to arbitrary derivations, so
-  # it will hopefully not make us cry, at least.
-  useCppNixOverlay =
-    lib.genAttrs overridelist_upstream (
-      name:
-      if (lib.functionArgs prev.${name}.override ? "nix") then
-        let
-          # Get the two common inputs of a derivation/package.
-          inputs = prev.${name}.buildInputs ++ prev.${name}.nativeBuildInputs;
-          nixDependency = lib.findFirst
-            (drv: (drv.pname or "") == "nix")
-            final.nixVersions.stable_upstream # default to stable nix if nix is not an input
-            inputs;
-          nixMajor = lib.versions.major (nixDependency.version or "");
-          nixMinor = lib.versions.minor (nixDependency.version or "");
-          nixAttr = "nix_${nixMajor}_${nixMinor}";
-          finalNix = final.nixVersions.${nixAttr};
-        in
-        prev.${name}.override {
-          nix = finalNix;
-        }
-      else prev.${name}
-    );
-
-  overlay = useCppNixOverlay // {
     lix-overlay-present = 1;
     # used for things that one wouldn't necessarily want to update, but we
     # nevertheless shove it in the overlay and fixed-point it in case one *does*
     # want to do that.
     lix-sources = import ./pins.nix;
 
-    lix = maybeWarnWrongMajor (maybeWarnDuplicate lixPackageToUse);
+    nixVersions = prev.nixVersions // rec {
-
+      # FIXME: do something less scuffed
-    nixVersions = prev.nixVersions // {
+      nix_2_18 = maybeWarnDuplicate lixPkg;
-      stable = final.lix;
+      stable = nix_2_18;
-      stable_upstream = prev.nixVersions.stable;
+      nix_2_18_upstream = prev.nixVersions.nix_2_18;
     };
 
     nix-eval-jobs = (prev.nix-eval-jobs.override {
       # lix
-      nix = final.lix;
+      nix = final.nixVersions.nix_2_18;
     }).overrideAttrs (old:
       let src = final.lix-sources.nix-eval-jobs;
       in {
-        version = "2.92.0-lix-${builtins.substring 0 7 src.rev}";
+        version = "2.90.0-lix-${builtins.substring 0 7 src.rev}";
 
         # FIXME: should this be patches instead?
         inherit src;
@@ -118,7 +80,9 @@ let
       }
     );
 
-    nix-doc = prev.nix-doc.override { withPlugin = false; };
+    nix-doc = prev.callPackage ./nix-doc/package.nix { withPlugin = false; };
+
+    pegtl = prev.callPackage ./pegtl.nix { };
   };
 in
   # Make the overlay idempotent, since flakes passing nixos modules around by

pegtl.nix

@@ -0,0 +1,23 @@
+{
+  stdenv,
+  cmake,
+  ninja,
+  fetchFromGitHub,
+}:
+
+stdenv.mkDerivation {
+  pname = "pegtl";
+  version = "3.2.7";
+
+  src = fetchFromGitHub {
+    repo = "PEGTL";
+    owner = "taocpp";
+    rev = "refs/tags/3.2.7";
+    hash = "sha256-IV5YNGE4EWVrmg2Sia/rcU8jCuiBynQGJM6n3DCWTQU=";
+  };
+
+  nativeBuildInputs = [
+    cmake
+    ninja
+  ];
+}

pins.json

@@ -1 +1 @@
-{"nix-eval-jobs": {"kind": "tarball", "rev": "912a9d63319e71ca131e16eea3348145a255db2e", "nar_hash": "sha256-6xMxT2duVMO6fo1AXfTjqh7LW3ZmNiHw6kBaAhweLGo=", "locked_url": "https://git.lix.systems/api/v1/repos/lix-project/nix-eval-jobs/archive/912a9d63319e71ca131e16eea3348145a255db2e.tar.gz?rev=912a9d63319e71ca131e16eea3348145a255db2e", "url": "https://git.lix.systems/lix-project/nix-eval-jobs/archive/main.tar.gz"}}
+{"nix-eval-jobs": {"kind": "tarball", "rev": "f8869bdcca7c1d5aaf37de3da3a4176811279a57", "nar_hash": "sha256-F/RvI9chHywnckEqHO1ggjzCayknhDnnl2kNnnVXpWg=", "locked_url": "https://git.lix.systems/api/v1/repos/lix-project/nix-eval-jobs/archive/f8869bdcca7c1d5aaf37de3da3a4176811279a57.tar.gz?rev=f8869bdcca7c1d5aaf37de3da3a4176811279a57", "url": "https://git.lix.systems/lix-project/nix-eval-jobs/archive/main.tar.gz"}}

test-nixos.nix

@@ -1,8 +1,5 @@
-{ pkgs, nixos, lix-module }:
+{ nixos, lix-module }:
 let
-  pkgs' = import pkgs.path {
-    inherit (pkgs) system;
-  };
   configs = {
     it-builds = nixos ({ ... }: {
       imports = [ lix-module ];
@@ -12,21 +9,10 @@ let
       system.stateVersion = "24.05";
     });
 
-    # Intentionally provoke the wrong major version.
-    # Does assume that the module is one major ahead of the release; the main
-    # purpose here is a manual testing fixture.
-    wrongMajor = pkgs'.nixos ({ ... }: {
-      imports = [ (import ./module.nix { lix = null; }) ];
-      documentation.enable = false;
-      fileSystems."/".device = "ignore-root-device";
-      boot.loader.grub.enable = false;
-      system.stateVersion = "24.05";
-    });
   };
 in
 {
   inherit configs;
 
   it-builds = configs.it-builds.config.system.build.toplevel;
-  wrongMajor = configs.wrongMajor.config.system.build.toplevel;
 }

version.json

@@ -1,3 +0,0 @@
-{
-    "version": "2.92.0-dev"
-}