Add an option to avoid passing the python hints

Signed-off-by: Cristian Le <[email protected]>

Author: LecrisUT

README.md

@@ -184,6 +184,11 @@ cmake.targets = ""
 # The CMAKE_TOOLCHAIN_FILE used for cross-compilation.
 cmake.toolchain-file = ""
 
+# Do not pass the current environment's python hints such as
+# ``Python_EXECUTABLE``. Primarily used for cross-compilation where the
+# CMAKE_TOOLCHAIN_FILE should handle it instead.
+cmake.no-python-hints = false
+
 # The versions of Ninja to allow. If Ninja is not present on the system or does
 # not pass this specifier, it will be downloaded via PyPI if possible. An empty
 # string will disable this check.

src/scikit_build_core/builder/builder.py

@@ -234,25 +234,26 @@ def configure(
         if self.settings.cmake.toolchain_file:
             cache_config["CMAKE_TOOLCHAIN_FILE"] = self.settings.cmake.toolchain_file
 
-        # Classic Find Python
-        cache_config["PYTHON_EXECUTABLE"] = sys.executable
-        cache_config["PYTHON_INCLUDE_DIR"] = python_include_dir
-        if python_library:
-            cache_config["PYTHON_LIBRARY"] = python_library
-
-        # Modern Find Python
-        for prefix in ("Python", "Python3"):
-            cache_config[f"{prefix}_EXECUTABLE"] = sys.executable
-            cache_config[f"{prefix}_ROOT_DIR"] = sys.base_exec_prefix
-            cache_config[f"{prefix}_INCLUDE_DIR"] = python_include_dir
-            cache_config[f"{prefix}_FIND_REGISTRY"] = "NEVER"
-            # FindPython may break if this is set - only useful on Windows
-            if python_library and sysconfig.get_platform().startswith("win"):
-                cache_config[f"{prefix}_LIBRARY"] = python_library
-            if python_sabi_library and sysconfig.get_platform().startswith("win"):
-                cache_config[f"{prefix}_SABI_LIBRARY"] = python_sabi_library
-            if numpy_include_dir:
-                cache_config[f"{prefix}_NumPy_INCLUDE_DIR"] = numpy_include_dir
+        if not self.settings.cmake.no_python_hints:
+            # Classic Find Python
+            cache_config["PYTHON_EXECUTABLE"] = sys.executable
+            cache_config["PYTHON_INCLUDE_DIR"] = python_include_dir
+            if python_library:
+                cache_config["PYTHON_LIBRARY"] = python_library
+
+            # Modern Find Python
+            for prefix in ("Python", "Python3"):
+                cache_config[f"{prefix}_EXECUTABLE"] = sys.executable
+                cache_config[f"{prefix}_ROOT_DIR"] = sys.base_exec_prefix
+                cache_config[f"{prefix}_INCLUDE_DIR"] = python_include_dir
+                cache_config[f"{prefix}_FIND_REGISTRY"] = "NEVER"
+                # FindPython may break if this is set - only useful on Windows
+                if python_library and sysconfig.get_platform().startswith("win"):
+                    cache_config[f"{prefix}_LIBRARY"] = python_library
+                if python_sabi_library and sysconfig.get_platform().startswith("win"):
+                    cache_config[f"{prefix}_SABI_LIBRARY"] = python_sabi_library
+                if numpy_include_dir:
+                    cache_config[f"{prefix}_NumPy_INCLUDE_DIR"] = numpy_include_dir
 
         cache_config["SKBUILD_SOABI"] = get_soabi(self.config.env, abi3=limited_api)
 

src/scikit_build_core/resources/scikit-build.schema.json

@@ -106,6 +106,11 @@
         "toolchain-file": {
           "type": "string",
           "description": "The CMAKE_TOOLCHAIN_FILE used for cross-compilation."
+        },
+        "no-python-hints": {
+          "type": "boolean",
+          "default": false,
+          "description": "Do not pass the current environment's python hints such as ``Python_EXECUTABLE``. Primarily used for cross-compilation where the CMAKE_TOOLCHAIN_FILE should handle it instead."
         }
       }
     },

src/scikit_build_core/settings/skbuild_model.py

@@ -108,6 +108,13 @@ class CMakeSettings:
     The CMAKE_TOOLCHAIN_FILE used for cross-compilation.
     """
 
+    no_python_hints: bool = False
+    """
+    Do not pass the current environment's python hints such as ``Python_EXECUTABLE``.
+    Primarily used for cross-compilation where the CMAKE_TOOLCHAIN_FILE should handle it
+    instead.
+    """
+
 
 @dataclasses.dataclass
 class SearchSettings: