conanfile.py

# The MIT License (MIT)
#
# Copyright (c) 2018 Mateusz Pusz
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import os
import re

from conan import ConanFile
from conan.errors import ConanInvalidConfiguration
from conan.tools.build import can_run, default_cppstd, valid_min_cppstd
from conan.tools.cmake import CMake, CMakeDeps, CMakeToolchain, cmake_layout
from conan.tools.files import copy, load, rm
from conan.tools.scm import Version

required_conan_version = ">=2.0.15"


class MPUnitsConan(ConanFile):
    name = "mp-units"
    homepage = "https://github.com/mpusz/mp-units"
    description = "The quantities and units library for C++"
    topics = (
        "units",
        "dimensions",
        "quantities",
        "dimensional-analysis",
        "physical-quantities",
        "physical-units",
        "system-of-units",
        "system-of-quantities",
        "isq",
        "si",
        "library",
        "quantity-manipulation",
    )
    license = "MIT"
    url = "https://github.com/mpusz/mp-units"
    settings = "os", "arch", "compiler", "build_type"
    options = {
        "cxx_modules": [True, False],
        "import_std": [True, False],
        "std_format": [True, False],
        "no_crtp": [True, False],
        "contracts": ["none", "std", "gsl-lite", "ms-gsl"],
        "freestanding": [True, False],
    }
    default_options = {
        # "cxx_modules" default set in config_options()
        # "import_std" default set in config_options()
        # "std_format" default set in config_options()
        # "no_crtp" default set in config_options()
        "import_std": False,  # still experimental in CMake
        "contracts": "gsl-lite",
        "freestanding": False,
    }
    # third-party libraries exercised by the linear algebra integration example and tests. These are
    # never runtime requirements of mp-units: the integration headers are dependency-free (guarded
    # by `__has_include`) and always ship; only the optional C++ modules are compiled against a
    # library, and only when it happens to be available (e.g. in the `build_all` developer build).
    _linear_algebra_libs = ["eigen/5.0.1", "glm/1.0.1", "blaze/3.8.2"]
    implements = ["auto_header_only"]
    exports = "LICENSE.md"
    exports_sources = (
        "docs/*",
        "src/*",
        "test/*",
        "cmake/*",
        "example/*",
        "CMakeLists.txt",
    )
    no_copy_source = True

    @property
    def _feature_compatibility(self):
        return {
            "minimum_support": {
                "min_cppstd": "20",
                "compiler": {
                    "gcc": "12",
                    "clang": "16",
                    "apple-clang": "15",
                    "msvc": "195",
                },
            },
            "std_format": {
                "min_cppstd": "20",
                "compiler": {
                    "gcc": "13",
                    "clang": "17",
                    "apple-clang": "16",
                    "msvc": "195",
                },
            },
            "cxx_modules": {
                "min_cppstd": "20",
                "compiler": {"gcc": "", "clang": "17", "apple-clang": "", "msvc": ""},
            },
            "import_std": {
                "min_cppstd": "23",
                "compiler": {
                    "gcc": "15",
                    "clang": "18",
                    "apple-clang": "",
                    "msvc": "195",
                },
            },
            "explicit_this": {
                "min_cppstd": "23",
                "compiler": {
                    "gcc": "14",
                    "clang": "18",
                    "apple-clang": "17",
                    "msvc": "195",
                },
            },
            "std_contracts": {
                "min_cppstd": "26",
                "compiler": {
                    "gcc": "16",
                    "clang": "",
                    "apple-clang": "",
                    "msvc": "",
                },
            },
        }

    @property
    def _option_feature_map(self):
        return {
            "std_format": "std_format",
            "cxx_modules": "cxx_modules",
            # "import_std": "import_std",  # still experimental in CMake
            "no_crtp": "explicit_this",
        }

    def _set_default_option(self, name):
        compiler = self.settings.compiler
        feature_name = self._option_feature_map[name]
        feature = self._feature_compatibility[feature_name]
        min_version = feature["compiler"].get(str(compiler))
        setattr(
            self.options,
            name,
            bool(
                min_version
                and Version(compiler.version) >= min_version
                and valid_min_cppstd(self, feature["min_cppstd"])
            ),
        )

    def _check_feature_supported(self, name, feature_name=name):
        compiler = self.settings.compiler
        cppstd = compiler.get_safe("cppstd", default_cppstd(self))
        feature = self._feature_compatibility[feature_name]

        # check C++ version
        if not valid_min_cppstd(self, feature["min_cppstd"]):
            raise ConanInvalidConfiguration(
                f"'{name}' requires at least cppstd={feature['min_cppstd']} ({cppstd} in use)",
            )

        # check compiler version
        min_version = feature["compiler"].get(str(compiler))
        if min_version == None:
            # not tested compiler being used - use at your own risk
            return
        if min_version == "":
            raise ConanInvalidConfiguration(
                f"'{name}' is not yet supported by any known {compiler} version"
            )
        if Version(compiler.version) < min_version:
            raise ConanInvalidConfiguration(
                f"'{name}' requires at least {compiler}-{min_version} ({compiler}-{compiler.version} in use)"
            )

    @property
    def _build_all(self):
        return bool(self.conf.get("user.mp-units.build:all", default=False))

    @property
    def _run_clang_tidy(self):
        return bool(self.conf.get("user.mp-units.analyze:clang-tidy", default=False))

    def set_version(self):
        content = load(self, os.path.join(self.recipe_folder, "src/CMakeLists.txt"))
        version = re.search(
            r"project\([^\)]+VERSION (\d+\.\d+\.\d+)[^\)]*\)", content
        ).group(1)
        self.version = version.strip()

    def config_options(self):
        for key in self._option_feature_map.keys():
            self._set_default_option(key)
        # TODO mixing of `import std;` and regular header files includes does not work for now
        if self.options.import_std:
            self.options.contracts = "none"

    def configure(self):
        if self.options.cxx_modules:
            self.package_type = "static-library"
        else:
            self.package_type = "header-library"
        if self.options.freestanding:
            self.options.rm_safe("std_format")

    def requirements(self):
        if not self.options.freestanding:
            if self.options.contracts == "gsl-lite":
                self.requires("gsl-lite/1.0.1", transitive_headers=True)
            elif self.options.contracts == "ms-gsl":
                self.requires("ms-gsl/4.2.0", transitive_headers=True)
            if not self.options.std_format:
                self.requires("fmt/12.1.0", transitive_headers=True)

    def build_requirements(self):
        self.tool_requires("cmake/[>=4.4.0 <5]")
        if self.options.freestanding:
            return
        if self._build_all:
            self.test_requires("catch2/3.11.0")
        # Make the linear algebra libraries available in the BUILD context
        # A consumer that later uses an integration pulls its library in via
        # `find_package(mp-units-integrations-<lib>)`, not via mp-units itself.
        if self._build_all or self.options.get_safe("cxx_modules"):
            for ref in self._linear_algebra_libs:
                self.test_requires(ref)

    def validate(self):
        compiler = self.settings.compiler
        if compiler == "clang" and Version(compiler.version).major == 19:
            raise ConanInvalidConfiguration(
                "clang-19 does not build mp-units because of an unfixable bug in the compiler."
            )
        if compiler == "apple-clang" and Version(compiler.version).major == 17:
            raise ConanInvalidConfiguration(
                "apple-clang-17 (Xcode 16.3+) does not build mp-units "
                + "because it has the same unfixable bug as clang-19."
            )

        self._check_feature_supported("mp-units", "minimum_support")
        for key, value in self._option_feature_map.items():
            if self.options.get_safe(key) == True:
                self._check_feature_supported(key, value)
        if self.options.contracts == "std":
            self._check_feature_supported("contracts", "std_contracts")
        # third-party contract libraries require a hosted implementation; C++26 contracts
        # are a language feature (the application has to provide a contract-violation
        # handler or compile with an evaluation semantic that does not need one)
        if self.options.freestanding and self.options.contracts not in ["none", "std"]:
            raise ConanInvalidConfiguration(
                "'contracts' should be set to 'none' or 'std' for a freestanding build"
            )
        # TODO mixing of `import std;` and regular header files includes does not work for now
        if self.options.import_std:
            # C++26 contracts are a language feature and do not bring any third-party
            # library headers that would conflict with `import std;`
            if self.options.contracts not in ["none", "std"]:
                raise ConanInvalidConfiguration(
                    "'contracts' should be set to 'none' or 'std' to use `import std;`"
                )
            if not self.options.get_safe("std_format", default=True):
                raise ConanInvalidConfiguration(
                    "'std_format' should be enabled to use `import std;`"
                )
        # MSVC Debug + std::format triggers error C7595 ("call to immediate function is not
        # a constant expression") on heavily templated quantity types — the
        # std::basic_format_string consteval ctor can't be evaluated under Debug's stricter
        # constant evaluator.  Release works; {fmt} works.  Mirror the CI matrix's
        # exclusion of this combination here so a local repro fails fast at install time.
        if (
            compiler == "msvc"
            and self.settings.build_type == "Debug"
            and self.options.get_safe("std_format", default=True)
        ):
            raise ConanInvalidConfiguration(
                "'std_format' is not supported on MSVC Debug builds (C7595: consteval "
                "format-string ctor fails on deeply templated quantity arguments). "
                "Use 'std_format=False' to build with {fmt} instead, or build Release."
            )

    def layout(self):
        cmake_layout(self)

    def generate(self):
        opt = self.options
        tc = CMakeToolchain(self)
        tc.absolute_paths = True  # only needed for CMake CI
        if self._build_all:
            tc.cache_variables["CMAKE_EXPORT_COMPILE_COMMANDS"] = True
            tc.cache_variables["CMAKE_COMPILE_WARNING_AS_ERROR"] = True
            tc.cache_variables["CMAKE_VERIFY_INTERFACE_HEADER_SETS"] = (
                not opt.import_std
            )
            if self._run_clang_tidy:
                tc.cache_variables["MP_UNITS_DEV_CLANG_TIDY"] = True
        tc.cache_variables["MP_UNITS_BUILD_CXX_MODULES"] = opt.cxx_modules
        if opt.cxx_modules or opt.import_std:
            tc.cache_variables["CMAKE_CXX_SCAN_FOR_MODULES"] = True
        if opt.import_std:
            tc.cache_variables["CMAKE_CXX_MODULE_STD"] = True
            # Current experimental support according to `Help/dev/experimental.rst`
            tc.cache_variables["CMAKE_EXPERIMENTAL_CXX_IMPORT_STD"] = (
                "f35a9ac6-8463-4d38-8eec-5d6008153e7d"
            )

        # TODO remove the below when Conan will learn to handle C++ modules
        if opt.freestanding:
            tc.cache_variables["MP_UNITS_API_FREESTANDING"] = True
            # Fix for freestanding builds: CMake compiler tests fail when linking with -ffreestanding
            # Set CMAKE_TRY_COMPILE_TARGET_TYPE to STATIC_LIBRARY to avoid linking during compiler tests
            tc.cache_variables["CMAKE_TRY_COMPILE_TARGET_TYPE"] = "STATIC_LIBRARY"
        else:
            tc.cache_variables["MP_UNITS_API_STD_FORMAT"] = opt.std_format
        tc.cache_variables["MP_UNITS_API_NO_CRTP"] = opt.no_crtp
        tc.cache_variables["MP_UNITS_API_CONTRACTS"] = str(opt.contracts).upper()

        tc.generate()
        deps = CMakeDeps(self)
        deps.generate()

    def build(self):
        cmake = CMake(self)
        cmake.configure(build_script_folder=None if self._build_all else "src")
        if self._build_all or self.options.cxx_modules:
            cmake.build()
        if self._build_all:
            if not self.options.import_std:
                cmake.build(target="all_verify_interface_header_sets")
            if can_run(self):
                cmake.ctest(cli_args=["--output-on-failure"])

    def package(self):
        copy(
            self,
            "LICENSE.md",
            self.source_folder,
            os.path.join(self.package_folder, "licenses"),
        )
        cmake = CMake(self)
        cmake.install()
        # TODO remove the below when Conan will learn to handle C++ modules
        if not self.options.cxx_modules:
            # CMakeDeps regenerates the package config from cpp_info when
            # cxx_modules is off, so the bundled `mp-unitsConfig.cmake` /
            # `mp-unitsTargets*.cmake` exports would conflict. Remove only
            # those — keep helper scripts like `import-std-setup.cmake`,
            # which `cmake_build_modules` points at for import_std consumers.
            cmake_dir = os.path.join(self.package_folder, "lib", "cmake", "mp-units")
            rm(self, "mp-unitsConfig.cmake", cmake_dir)
            rm(self, "mp-unitsConfigVersion.cmake", cmake_dir)
            rm(self, "mp-unitsTargets*.cmake", cmake_dir)

    def package_info(self):
        compiler = self.settings.compiler
        # TODO remove the branch when Conan will learn to handle C++ modules
        if self.options.cxx_modules:
            # CMakeDeps does not generate C++ modules definitions for now
            # Skip the Conan-generated files and use the mp-unitsConfig.cmake bundled with mp-units
            self.cpp_info.set_property("cmake_find_mode", "none")
            self.cpp_info.builddirs = ["."]
        else:
            # handle contracts
            if self.options.contracts == "none":
                self.cpp_info.components["core"].defines.append(
                    "MP_UNITS_API_CONTRACTS=0"
                )
            elif self.options.contracts == "std":
                self.cpp_info.components["core"].defines.append(
                    "MP_UNITS_API_CONTRACTS=1"
                )
                if self.settings.compiler == "gcc":
                    self.cpp_info.components["core"].cxxflags.append("-fcontracts")
                    if not self.options.freestanding:
                        # the default contract-violation handler lives in the experimental
                        # library; a freestanding application has to provide its own handler
                        # (or compile with `-fcontract-evaluation-semantic=quick_enforce`)
                        self.cpp_info.components["core"].system_libs.append("stdc++exp")
            elif self.options.contracts == "gsl-lite":
                self.cpp_info.components["core"].requires.append("gsl-lite::gsl-lite")
                self.cpp_info.components["core"].defines.append(
                    "MP_UNITS_API_CONTRACTS=2"
                )
            elif self.options.contracts == "ms-gsl":
                self.cpp_info.components["core"].requires.append("ms-gsl::ms-gsl")
                self.cpp_info.components["core"].defines.append(
                    "MP_UNITS_API_CONTRACTS=3"
                )

            # handle API options
            self.cpp_info.components["core"].defines.append(
                "MP_UNITS_API_NO_CRTP=" + str(int(self.options.no_crtp == True))
            )

            # handle hosted configuration
            if self.options.freestanding:
                self.cpp_info.components["core"].defines.append("MP_UNITS_HOSTED=0")
                if compiler == "msvc":
                    self.cpp_info.components["core"].cxxflags.append("/kernel")
                else:
                    self.cpp_info.components["core"].cxxflags.append("-ffreestanding")
            else:
                self.cpp_info.components["core"].defines.append("MP_UNITS_HOSTED=1")
                if not self.options.std_format:
                    self.cpp_info.components["core"].requires.append("fmt::fmt")
                self.cpp_info.components["core"].defines.append(
                    "MP_UNITS_API_STD_FORMAT="
                    + str(int(self.options.std_format == True))
                )

            # handle import std
            if self.options.import_std:
                self.cpp_info.components["core"].defines.append("MP_UNITS_IMPORT_STD")
                if compiler == "clang" and Version(compiler.version) < 19:
                    self.cpp_info.components["core"].cxxflags.append(
                        "-Wno-deprecated-declarations"
                    )
                # Ship the import-std-setup.cmake snippet that escalates the
                # compiler-specific flags needed for `import std;` to project-wide
                # compile options, so CMake's implicit std module BMI is built
                # with matching preprocessor / warning state (MSVC C5050, Clang 21
                # reserved-module-identifier). `cmake_find_mode = "none"` consumers
                # (cxx_modules=True) get the same snippet through the bundled
                # mp-unitsConfig.cmake instead.
                self.cpp_info.components["core"].set_property(
                    "cmake_build_modules",
                    [
                        os.path.join(
                            "lib", "cmake", "mp-units", "import-std-setup.cmake"
                        )
                    ],
                )

            if compiler == "msvc":
                self.cpp_info.components["core"].cxxflags.append("/utf-8")

            self.cpp_info.components["systems"].requires = ["core"]

            # Add-on representation types and helpers (cartesian/polar vectors, tensors, constrained,
            # safe_int, random) layered above systems; everything beyond the standardizable core.
            self.cpp_info.components["utility"].requires = ["core", "systems"]

            # The dependency-free integration headers (`mp-units::integrations`). Mirrors the CMake
            # target exported in `mp-unitsTargets`. The third-party backends stay out of the dependency
            # graph: they are pulled in only by the separate `find_package(mp-units-integrations-<lib>)`
            # packages, never by mp-units itself.
            #
            # The per-backend `mp-units::integrations-<lib>` targets are intentionally NOT surfaced as
            # Conan components. They are a CMake-level feature for source consumers (`add_subdirectory`/
            # FetchContent) and raw `cmake --install` users, where the backend is found at configure time
            # and the module is built from source. Conan consumers instead link `mp-units::integrations`
            # (always-shipped, dependency-free headers) plus their own copy of the linear algebra library
            # (see `test_package`). Making them Conan components would force opt-in host dependencies on
            # mp-units for a benefit that only fully lands once module consumption from an installed
            # package is supported - revisit then.
            self.cpp_info.components["integrations"].requires = ["core"]

            # https://github.com/llvm/llvm-project/issues/131410
            if (
                compiler == "clang"
                and Version(compiler.version).major == 20
                and Version(compiler.version).minor == 1
            ):
                self.cpp_info.components["core"].cxxflags.append("-Wno-unused-result")