python3Packages.ruff: reuse already built ruff binary (#412112)

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

@@ -1,8 +1,8 @@
 {
   buildPythonPackage,
+  hatchling,
+  lib,
   ruff,
-  rustPlatform,
-  installShellFiles,
 }:
 
 buildPythonPackage {
@@ -10,26 +10,38 @@ buildPythonPackage {
     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 = [
+  build-system = [ hatchling ];
-    installShellFiles
+
-    rustPlatform.cargoSetupHook
+  postPatch =
-    rustPlatform.maturinBuildHook
+    # Do not rely on path lookup at runtime to find the ruff binary.
-  ];
+    # Use the propagated binary instead.
+    ''
+      substituteInPlace python/ruff/__main__.py \
+        --replace-fail \
+          'ruff_exe = "ruff" + sysconfig.get_config_var("EXE")' \
+          'return "${lib.getExe ruff}"'
+    ''
+    # Sidestep the maturin build system in favour of reusing the binary already built by nixpkgs,
+    # to avoid rebuilding the ruff binary for every active python package set.
+    + ''
+      substituteInPlace pyproject.toml \
+        --replace-fail 'requires = ["maturin>=1.0,<2.0"]' 'requires = ["hatchling"]' \
+        --replace-fail 'build-backend = "maturin"' 'build-backend = "hatchling.build"'
+
+      cat >> pyproject.toml <<EOF
+      [tool.hatch.build]
+      packages = ['python/ruff']
+
+      EOF
+    '';
+
+  postInstall = ''
+    mkdir -p $out/bin && ln -s ${lib.getExe ruff} $out/bin/ruff
+  '';
 
   pythonImportsCheck = [ "ruff" ];
 }