ruff: Build as a standalone without Python

Using `buildPythonPackage` make `ruff` propagate the Python used for the build, which might not be the same Python as you want in your development shell.

#350654 changed the ruff top-level attribute to be built with Python modules.
This doesn't actually make much sense, we have versioned Python sets, and including just the one Python in the top-level package isn't helpful, and causes issues downstream related to PATH & PYTHONPATH.

See my related [uv PR](#357113 (comment)).

Author: adisbladis

pkgs/by-name/ru/ruff-lsp/package.nix

@@ -36,7 +36,7 @@ python3Packages.buildPythonApplication rec {
     pytestCheckHook
     pytest-asyncio
     python-lsp-jsonrpc
-    ruff.bin
+    ruff
     versionCheckHook
   ];
   versionCheckProgramArg = [ "--version" ];

pkgs/by-name/ru/ruff/package.nix

@@ -1,11 +1,12 @@
 {
   lib,
   stdenv,
-  python3Packages,
-  fetchFromGitHub,
   rustPlatform,
+  fetchFromGitHub,
   installShellFiles,
+
   rust-jemalloc-sys,
+  buildPackages,
   versionCheckHook,
 
   # passthru
@@ -14,15 +15,9 @@
   nix-update-script,
 }:
 
-python3Packages.buildPythonPackage rec {
+rustPlatform.buildRustPackage rec {
   pname = "ruff";
   version = "0.8.4";
-  pyproject = true;
-
-  outputs = [
-    "bin"
-    "out"
-  ];
 
   src = fetchFromGitHub {
     owner = "astral-sh";
@@ -31,46 +26,29 @@ python3Packages.buildPythonPackage rec {
     hash = "sha256-c5d2XaoEjCHWMdjTLD6CnwP8rpSXTUrmKSs0QWQ6UG0=";
   };
 
-  # Do not rely on path lookup at runtime to find the ruff binary
-  postPatch = ''
-    substituteInPlace python/ruff/__main__.py \
-      --replace-fail \
-        'ruff_exe = "ruff" + sysconfig.get_config_var("EXE")' \
-        'return "${placeholder "bin"}/bin/ruff"'
-  '';
+  useFetchCargoVendor = true;
+  cargoHash = "sha256-jbUjsIJRpkKYc+qHN8tkcZrcjPTFJfdCsatezzdX4Ss=";
 
-  cargoDeps = rustPlatform.fetchCargoVendor {
-    inherit pname version src;
-    hash = "sha256-jbUjsIJRpkKYc+qHN8tkcZrcjPTFJfdCsatezzdX4Ss=";
-  };
-
-  nativeBuildInputs =
-    [ installShellFiles ]
-    ++ (with rustPlatform; [
-      cargoSetupHook
-      maturinBuildHook
-      cargoCheckHook
-    ]);
+  nativeBuildInputs = [ installShellFiles ];
 
   buildInputs = [
     rust-jemalloc-sys
   ];
 
   postInstall =
+    let
+      emulator = stdenv.hostPlatform.emulator buildPackages;
+    in
     ''
-      mkdir -p $bin/bin
-      mv $out/bin/ruff $bin/bin/
-      rmdir $out/bin
-    ''
-    + lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
       installShellCompletion --cmd ruff \
-        --bash <($bin/bin/ruff generate-shell-completion bash) \
-        --fish <($bin/bin/ruff generate-shell-completion fish) \
-        --zsh <($bin/bin/ruff generate-shell-completion zsh)
+        --bash <(${emulator} $out/bin/ruff generate-shell-completion bash) \
+        --fish <(${emulator} $out/bin/ruff generate-shell-completion fish) \
+        --zsh <(${emulator} $out/bin/ruff generate-shell-completion zsh)
     '';
 
   # Run cargo tests
-  cargoCheckType = "debug";
+  checkType = "debug";
+
   # tests do not appear to respect linker options on doctests
   # Upstream issue: https://github.com/rust-lang/cargo/issues/14189
   # This causes errors like "error: linker `cc` not found" on static builds
@@ -106,12 +84,11 @@ python3Packages.buildPythonPackage rec {
     "--skip=unix::symlink_inside_workspace"
   ];
 
-  nativeCheckInputs = [
+  nativeInstallCheckInputs = [
     versionCheckHook
   ];
   versionCheckProgramArg = [ "--version" ];
-
-  pythonImportsCheck = [ "ruff" ];
+  doInstallCheck = true;
 
   passthru = {
     tests =

pkgs/development/python-modules/ruff/default.nix

@@ -0,0 +1,35 @@
+{
+  buildPythonPackage,
+  pkgs,
+  rustPlatform,
+  installShellFiles,
+}:
+
+buildPythonPackage {
+  inherit (pkgs.ruff)
+    pname
+    version
+    src
+    cargoDeps
+    postInstall
+    meta
+    ;
+
+  # Do not rely on path lookup at runtime to find the ruff binary
+  postPatch = ''
+    substituteInPlace python/ruff/__main__.py \
+      --replace-fail \
+        'ruff_exe = "ruff" + sysconfig.get_config_var("EXE")' \
+        'return "${placeholder "out"}/bin/ruff"'
+  '';
+
+  pyproject = true;
+
+  nativeBuildInputs = [
+    installShellFiles
+    rustPlatform.cargoSetupHook
+    rustPlatform.maturinBuildHook
+  ];
+
+  pythonImportsCheck = [ "ruff" ];
+}

pkgs/top-level/python-packages.nix

@@ -14282,9 +14282,7 @@ self: super: with self; {
 
   rubymarshal = callPackage ../development/python-modules/rubymarshal { };
 
-  ruff = toPythonModule (pkgs.ruff.override {
-    python3Packages = self;
-  });
+  ruff = callPackage ../development/python-modules/ruff { };
 
   ruff-api = callPackage ../development/python-modules/ruff-api { };