Build Requires Example

Author: Behemyth

examples/conan_cmake/build_requires/CMakeLists.txt

@@ -1,10 +1,19 @@
 cmake_minimum_required(VERSION 3.24)
 
-project(FormatOutput LANGUAGES CXX C)
+project(BuildRequiresExample LANGUAGES CXX)
 
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-find_package(fmt REQUIRED)
+# Find the abseil package (provided by CMakeDeps generator)
+find_package(absl REQUIRED)
 
+# Create the executable
 add_executable(main main.cpp)
-target_link_libraries(main PRIVATE fmt::fmt)
+
+# Link against abseil libraries
+target_link_libraries(main PRIVATE
+    absl::strings
+    absl::str_format
+    absl::base
+)

examples/conan_cmake/build_requires/conanfile.py

@@ -0,0 +1,54 @@
+"""Conan recipe demonstrating tool_requires with CMake and abseil dependency.
+
+This example shows how to use tool_requires to specify build-time dependencies
+like CMake, while using regular requires for runtime dependencies like abseil.
+"""
+
+from conan import ConanFile
+from conan.tools.cmake import CMake, cmake_layout
+
+
+class BuildRequiresExample(ConanFile):
+    """Example Conan recipe demonstrating tool_requires with CMake and abseil."""
+
+    name = 'build_requires_example'
+    version = '1.0'
+
+    # Basic package configuration
+    settings = 'os', 'compiler', 'build_type', 'arch'
+
+    # Regular dependencies - libraries we link against
+    requires = 'abseil/20240116.2'
+
+    # Build dependencies - tools needed during build
+    tool_requires = 'cmake/[>=3.24]'
+
+    # Generators for CMake integration
+    generators = 'CMakeToolchain', 'CMakeDeps'
+
+    def layout(self):
+        """Define the layout for the project."""
+        cmake_layout(self)
+
+    def configure(self):
+        """Configure package options based on settings."""
+        # Example: Configure abseil options if needed
+        # self.options["abseil"].shared = False
+        pass
+
+    def build_requirements(self):
+        """Additional build requirements logic if needed."""
+        # This method can be used for conditional build requirements
+        # For example, only require certain tools on specific platforms
+        pass
+
+    def build(self):
+        """Build the project using CMake."""
+        cmake = CMake(self)
+        cmake.configure()
+        cmake.build()
+
+    def package(self):
+        """Package the built artifacts."""
+        cmake = CMake(self)
+        cmake.install()

examples/conan_cmake/build_requires/main.cpp

@@ -1,7 +1,25 @@
-#include "fmt/color.h"
+#include <iostream>
+#include "absl/strings/str_format.h"
+#include "absl/strings/string_view.h"
+#include "absl/base/macros.h"
 
 int main()
 {
-    fmt::print(fg(fmt::terminal_color::cyan), "Hello fmt {}!\n", FMT_VERSION);
+    // Demonstrate abseil string formatting
+    absl::string_view greeting = "Hello";
+    std::string name = "Abseil";
+
+    // Use absl::StrFormat instead of printf-style formatting
+    std::string formatted = absl::StrFormat("%s %s! Version: %s",
+                                            greeting, name,
+                                            ABSL_PACKAGE_VERSION);
+
+    std::cout << formatted << std::endl;
+
+    // Demonstrate some abseil string operations
+    std::string message = absl::StrFormat("This example shows tool_requires with CMake %s",
+                                          "working correctly!");
+    std::cout << message << std::endl;
+
     return 0;
 }

examples/conan_cmake/build_requires/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
-description = "A simple project showing how to use conan with CPPython"
-name = "cppython-conan-cmake-simple"
+description = "Example showing tool_requires with CMake and abseil dependency"
+name = "cppython-conan-cmake-build-requires"
 version = "1.0.0"
 
 license = { text = "MIT" }
@@ -18,7 +18,11 @@ provider-name = "conan"
 
 install-path = "install"
 
-dependencies = ["fmt>=11.2.0"]
+dependencies = ["abseil/20240116.2"]
+
+# Future tool_requires support (not yet implemented in CPPython):
+# [tool.cppython.provider.tool_requires]
+# cmake = ">=3.20"
 
 [tool.cppython.generator]
 

tests/integration/examples/test_conan_cmake.py

@@ -59,3 +59,43 @@ def test_simple(example_runner: CliRunner) -> None:
 
         # Publish the project to the local cache
         publish_project.publish()
+
+    @staticmethod
+    def test_build_requires(example_runner: CliRunner) -> None:
+        """build_requires project"""
+        # Create project configuration
+        project_root = Path.cwd()
+        project_configuration = ProjectConfiguration(project_root=project_root, version=None, verbosity=2, debug=True)
+
+        # Create console interface
+        interface = ConsoleInterface()
+
+        # Load pyproject.toml data
+        pyproject_path = project_root / 'pyproject.toml'
+        pyproject_data = loads(pyproject_path.read_text(encoding='utf-8'))
+
+        # Create and use the project directly
+        project = Project(project_configuration, interface, pyproject_data)
+
+        # Call install directly to get structured results
+        project.install()
+
+        # Run the CMake configuration command
+        result = subprocess.run(['cmake', '--preset=default'], capture_output=True, text=True, check=False)
+
+        assert result.returncode == 0, f'Cmake failed: {result.stderr}'
+
+        path = Path('build').absolute()
+
+        # Verify that the build directory contains the expected files
+        assert (path / 'CMakeCache.txt').exists(), f'{path / "CMakeCache.txt"} not found'
+
+        # --- Setup for Publish with modified config ---
+        # Modify the in-memory representation of the pyproject data
+        pyproject_data['tool']['cppython']['provider']['remotes'] = []
+
+        # Create a new project instance with the modified configuration for the 'publish' step
+        publish_project = Project(project_configuration, interface, pyproject_data)
+
+        # Publish the project to the local cache
+        publish_project.publish()