CMakePackage: Add option to get cmake args from dependencies

repos/spack_repo/builtin/build_systems/cmake.py

@@ -42,24 +42,6 @@ def _extract_primary_generator(generator):
     return _primary_generator_extractor.match(generator).group(1)
 
 
-def _maybe_set_python_hints(pkg: PackageBase, args: List[str]) -> None:
-    """Set the PYTHON_EXECUTABLE, Python_EXECUTABLE, and Python3_EXECUTABLE CMake variables
-    if the package has Python as build or link dep and ``find_python_hints`` is set to True. See
-    ``find_python_hints`` for context."""
-    if not getattr(pkg, "find_python_hints", False) or not pkg.spec.dependencies(
-        "python", deptype=("build", "link")
-    ):
-        return
-    python_executable = pkg.spec["python"].command.path
-    args.extend(
-        [
-            define("PYTHON_EXECUTABLE", python_executable),
-            define("Python_EXECUTABLE", python_executable),
-            define("Python3_EXECUTABLE", python_executable),
-        ]
-    )
-
-
 def _supports_compilation_databases(pkg: PackageBase) -> bool:
     """Check if this package (and CMake) can support compilation databases."""
 
@@ -172,20 +154,16 @@ class CMakePackage(PackageBase):
     https://cmake.org/cmake/help/latest/
     """
 
+    #: List of package names for which CMake argument injection should be disabled
+    disable_cmake_hints_from: List[str] = []
+
     #: This attribute is used in UI queries that need to know the build
     #: system base class
     build_system_class = "CMakePackage"
 
     #: Legacy buildsystem attribute used to deserialize and install old specs
     default_buildsystem = "cmake"
 
-    #: When this package depends on Python and ``find_python_hints`` is set to True, pass the
-    #: defines {Python3,Python,PYTHON}_EXECUTABLE explicitly, so that CMake locates the right
-    #: Python in its builtin FindPython3, FindPython, and FindPythonInterp modules. Spack does
-    #: CMake's job because CMake's modules by default only search for Python versions known at the
-    #: time of release.
-    find_python_hints = True
-
     build_system("cmake")
 
     with when("build_system=cmake"):
@@ -405,7 +383,25 @@ def std_args(pkg: PackageBase, generator: Optional[str] = None) -> List[str]:
             )
 
         _conditional_cmake_defaults(pkg, args)
-        _maybe_set_python_hints(pkg, args)
+
+        # Append extra hint/option arguments from dependencies
+        # TODO: Consider properties from virtual packages like Mpi
+        disable_cmake_hints_from = getattr(pkg, "disable_cmake_hints_from", [])
+        for dep in pkg.spec.edges_to_dependencies():
+            # Skip packages without the callback
+            dep_pkg = dep.spec.package
+            if not hasattr(dep_pkg, "dependent_cmake_args"):
+                continue
+
+            # Skip disabled dependency cmake args
+            if dep_pkg.name in disable_cmake_hints_from:
+                continue
+
+            # Skip disabled virtual dependency cmake args
+            if any(v in disable_cmake_hints_from for v in dep.virtuals):
+                continue
+
+            args.extend(dep_pkg.dependent_cmake_args(pkg.spec))
 
         return args
 

repos/spack_repo/builtin/packages/opencv/package.py

@@ -17,7 +17,7 @@ class Opencv(CMakePackage, CudaPackage):
     homepage = "https://opencv.org/"
     url = "https://github.com/opencv/opencv/archive/4.5.0.tar.gz"
     git = "https://github.com/opencv/opencv.git"
-    find_python_hints = False  # opencv uses custom OpenCVDetectPython.cmake
+    disable_cmake_hints_from = ["python"]  # opencv uses custom OpenCVDetectPython.cmake
 
     maintainers("bvanessen", "adamjstewart")
 

repos/spack_repo/builtin/packages/python/package.py

@@ -1324,6 +1324,16 @@ def setup_dependent_package(self, module, dependent_spec):
         module.python_platlib = join_path(dependent_spec.prefix, self.platlib)
         module.python_purelib = join_path(dependent_spec.prefix, self.purelib)
 
+    def dependent_cmake_args(self, dependent_spec: Spec) -> List[str]:
+        # pkg.spec["python"] can re-direct to python-venv if pkg extends python
+        # ref. https://github.com/spack/spack/pull/40773
+        python_executable = dependent_spec["python"].command.path
+        return [
+            f"-DPYTHON_EXECUTABLE:PATH={python_executable}",
+            f"-DPython_EXECUTABLE:PATH={python_executable}",
+            f"-DPython3_EXECUTABLE:PATH={python_executable}",
+        ]
+
     def add_files_to_view(self, view, merge_map, skip_if_exists=True):
         """Make the view a virtual environment if it isn't one already.
 

tests/build_systems.py

@@ -257,6 +257,12 @@ def test_cmake_std_args(self, default_mock_concretization):
         s = default_mock_concretization("mpich")
         assert cmake.CMakeBuilder.std_args(s.package)
 
+    def test_cmake_dependent_args(self, default_mock_concretization):
+        # Call the function on a CMakePackage instance
+        s = default_mock_concretization("cmake-client +cmake_hints")
+        args = cmake.CMakeBuilder.std_args(s.package)
+        assert '-DCMAKE_HINTS_ARG:STRING="Foo"' in args
+
     def test_cmake_bad_generator(self, default_mock_concretization):
         s = default_mock_concretization("cmake-client")
         with pytest.raises(InstallError):

tests/repos/spack_repo/builtin_mock/packages/cmake_client/package.py

@@ -30,8 +30,10 @@ class CmakeClient(CMakePackage):
     )
     variant("single", description="", default="blue", values=("blue", "red", "green"), multi=False)
     variant("truthy", description="", default=True)
+    variant("cmake_hints", description="", default=False)
 
     depends_on("c", type="build")
+    depends_on("cmake-hints", when="+cmake_hints")
 
     callback_counter = 0
 

tests/repos/spack_repo/builtin_mock/packages/cmake_hints/package.py

@@ -0,0 +1,24 @@
+# Copyright Spack Project Developers. See COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from typing import List
+
+from spack.package import Package, PackageBase, version
+
+
+def check(condition, msg):
+    """Raise an install error if condition is False."""
+    if not condition:
+        raise InstallError(msg)
+
+
+class CmakeHints(Package):
+    """A dummy package that uses cmake."""
+
+    homepage = "https://www.example.com"
+    url = "https://www.example.com/cmake-hints-1.0.tar.gz"
+    version("1.0", md5="4cb3ff35b2472aae70f542116d616e63")
+
+    def dependent_cmake_args(self, pkg: PackageBase) -> List[str]:
+        return ['-DCMAKE_HINTS_ARG:STRING="Foo"']