python3Packages.setuptools-rust: fix python version inconsistency (#473299)

pkgs/development/interpreters/python/passthrufun.nix

@@ -141,7 +141,13 @@ rec {
   pythonAtLeast = lib.versionAtLeast pythonVersion;
   pythonOlder = lib.versionOlder pythonVersion;
   inherit hasDistutilsCxxPatch;
-  inherit pythonOnBuildForHost;
+  inherit
+    pythonOnBuildForBuild
+    pythonOnBuildForHost
+    pythonOnBuildForTarget
+    pythonOnHostForHost
+    pythonOnTargetForTarget
+    ;
   inherit pythonABITags;
 
   tests = callPackage ./tests.nix {

pkgs/development/python-modules/setuptools-rust/default.nix

@@ -13,6 +13,7 @@
   setuptools-rust,
   setuptools-scm,
   replaceVars,
+  python,
   targetPackages,
 }:
 buildPythonPackage rec {
@@ -44,20 +45,12 @@ buildPythonPackage rec {
 
   # integrate the setup hook to set up the build environment for cross compilation
   # this hook is automatically propagated to consumers using setuptools-rust as build-system
-  #
-  # Only include the setup hook if targetPackages.python3 is defined.
-  # targetPackages.python3 is not always available, for example when including
-  # setuptools-rust via buildInputs instead of nativeBuildInputs or building it directly.
-  setupHook =
-    if !(targetPackages ? python3) then
-      null
-    else
-      replaceVars ./setuptools-rust-hook.sh {
-        pyLibDir = "${targetPackages.python3}/lib/${targetPackages.python3.libPrefix}";
-        cargoBuildTarget = stdenv.targetPlatform.rust.rustcTargetSpec;
-        cargoLinkerVar = stdenv.targetPlatform.rust.cargoEnvVarTarget;
-        targetLinker = "${targetPackages.stdenv.cc}/bin/${targetPackages.stdenv.cc.targetPrefix}cc";
-      };
+  setupHook = replaceVars ./setuptools-rust-hook.sh {
+    pyLibDir = "${python.pythonOnTargetForTarget}/lib/${python.pythonOnTargetForTarget.libPrefix}";
+    cargoBuildTarget = stdenv.targetPlatform.rust.rustcTargetSpec;
+    cargoLinkerVar = stdenv.targetPlatform.rust.cargoEnvVarTarget;
+    targetLinker = "${targetPackages.stdenv.cc}/bin/${targetPackages.stdenv.cc.targetPrefix}cc";
+  };
 
   passthru.tests = {
     pyo3 = maturin.tests.pyo3.override {