Added support for tools.cmake.cmaketoolchain:extra_variables

conan/tools/cmake/toolchain/blocks.py

@@ -1018,6 +1018,46 @@ def context(self):
                 "winsdk_version": winsdk_version,
                 "gen_platform_sdk_version": gen_platform_sdk_version}
 
+class ExtraVariablesBlock(Block):
+    template = textwrap.dedent(r"""
+        {% if extra_variables %}
+        {% for key, value in extra_variables.items() %}
+        set({{ key }} {{ value }})
+        {% endfor %}
+        {% endif %}
+    """)
+
+    CMAKE_CACHE_TYPES = ["BOOL","FILEPATH", "PATH", "STRING", "INTERNAL"]
+
+    def get_exact_type(self, key, value):
+        if isinstance(value, str):
+            return f"\"{value}\""
+        elif isinstance(value, (int, float)):
+            return value
+        elif isinstance(value, dict):
+            var_value = self.get_exact_type(key, value.get("value"))
+            is_cache = value.get("cache")
+            if is_cache:
+                if not isinstance(is_cache, bool):
+                    raise ConanException(f'tools.cmake.cmaketoolchain:extra_variables "cache" must be a boolean (True/False)')
+                var_type = value.get("type")
+                if not var_type:
+                    raise ConanException(f'tools.cmake.cmaketoolchain:extra_variables needs "type" defined for cache variable "{key}"')
+                if var_type not in self.CMAKE_CACHE_TYPES:
+                    raise ConanException(f'tools.cmake.cmaketoolchain:extra_variables invalid type "{var_type}" for cache variable "{key}". Possible types: {", ".join(self.CMAKE_CACHE_TYPES)}')
+                # Set docstring as variable name if not defined
+                docstring = value.get("docstring") or key
+                return f"{var_value} CACHE {var_type} \"{docstring}\""
+            else:
+                return var_value
+
+    def context(self):
+        # Reading configuration from "tools.cmake.cmaketoolchain:extra_variables"
+        extra_variables = self._conanfile.conf.get("tools.cmake.cmaketoolchain:extra_variables", default={}, check_type=dict)
+        parsed_extra_variables = {}
+        for key, value in extra_variables.items():
+            parsed_extra_variables[key] = self.get_exact_type(key, value)
+        return {"extra_variables": parsed_extra_variables}
 
 class OutputDirsBlock(Block):
 

conan/tools/cmake/toolchain/toolchain.py

@@ -9,7 +9,7 @@
 from conan.tools.build import use_win_mingw
 from conan.tools.cmake.presets import write_cmake_presets
 from conan.tools.cmake.toolchain import CONAN_TOOLCHAIN_FILENAME
-from conan.tools.cmake.toolchain.blocks import ToolchainBlocks, UserToolchain, GenericSystemBlock, \
+from conan.tools.cmake.toolchain.blocks import ExtraVariablesBlock, ToolchainBlocks, UserToolchain, GenericSystemBlock, \
     AndroidSystemBlock, AppleSystemBlock, FPicBlock, ArchitectureBlock, GLibCXXBlock, VSRuntimeBlock, \
     CppStdBlock, ParallelBlock, CMakeFlagsInitBlock, TryCompileBlock, FindFiles, PkgConfigBlock, \
     SkipRPath, SharedLibBock, OutputDirsBlock, ExtraFlagsBlock, CompilersBlock, LinkerScriptsBlock, \
@@ -165,6 +165,7 @@ def __init__(self, conanfile, generator=None):
                                        ("parallel", ParallelBlock),
                                        ("extra_flags", ExtraFlagsBlock),
                                        ("cmake_flags_init", CMakeFlagsInitBlock),
+                                       ("extra_variables", ExtraVariablesBlock),
                                        ("try_compile", TryCompileBlock),
                                        ("find_paths", FindFiles),
                                        ("pkg_config", PkgConfigBlock),

conans/model/conf.py

@@ -73,6 +73,7 @@
     "tools.cmake.cmaketoolchain:toolset_arch": "Toolset architecture to be used as part of CMAKE_GENERATOR_TOOLSET in CMakeToolchain",
     "tools.cmake.cmaketoolchain:toolset_cuda": "(Experimental) Path to a CUDA toolset to use, or version if installed at the system level",
     "tools.cmake.cmaketoolchain:presets_environment": "String to define wether to add or not the environment section to the CMake presets. Empty by default, will generate the environment section in CMakePresets. Can take values: 'disabled'.",
+    "tools.cmake.cmaketoolchain:extra_variables": "Dictionary with variables to be injected in CMakeToolchain (potential override of CMakeToolchain defined variables)",
     "tools.cmake.cmake_layout:build_folder_vars": "Settings and Options that will produce a different build folder and different CMake presets names",
     "tools.cmake.cmake_layout:build_folder": "(Experimental) Allow configuring the base folder of the build for local builds",
     "tools.cmake.cmake_layout:test_folder": "(Experimental) Allow configuring the base folder of the build for test_package",

test/integration/toolchains/cmake/test_cmaketoolchain.py

@@ -1501,7 +1501,6 @@ def layout(self):
     presets = json.loads(c.load(user_presets["include"][0]))
     assert os.path.isabs(presets["configurePresets"][0]["toolchainFile"])
 
-
 def test_output_dirs_gnudirs_local_default():
     # https://github.com/conan-io/conan/issues/14733
     c = TestClient()
@@ -1575,3 +1574,59 @@ def _assert_install(out):
     c.run("build .")
     _assert_install(c.out)
     assert "CMAKE_INSTALL_PREFIX" not in c.out
+
+
+def test_toolchain_extra_variables():
+    windows_profile = textwrap.dedent("""
+        [settings]
+        os=Windows
+        arch=x86_64
+        [conf]
+        tools.cmake.cmaketoolchain:extra_variables={'CMAKE_GENERATOR_INSTANCE': '${GENERATOR_INSTANCE}/buildTools/', 'FOO': '42' }
+        """)
+
+    client = TestClient()
+    client.save({"conanfile.txt": "[generators]\nCMakeToolchain",
+                 "windows": windows_profile})
+
+    # Test passing extra_variables from pro ile
+    client.run("install . --profile:host=windows")
+    toolchain = client.load("conan_toolchain.cmake")
+    assert 'set(CMAKE_GENERATOR_INSTANCE "${GENERATOR_INSTANCE}/buildTools/")' in toolchain
+    assert 'set(FOO "42")' in toolchain
+
+    # Test input from command line passing dict between doble quotes
+    client.run(textwrap.dedent(r"""
+        install . -c tools.cmake.cmaketoolchain:extra_variables="{'CMAKE_GENERATOR_INSTANCE': '${GENERATOR_INSTANCE}/buildTools/', 'FOO': 42.2, 'DICT': {'value': 1}, 'CACHE_VAR': {'value': 'hello world', 'cache': True, 'type': 'BOOL', 'docstring': 'test variable'}}"
+    """)
+    )
+
+    toolchain = client.load("conan_toolchain.cmake")
+    assert 'set(CMAKE_GENERATOR_INSTANCE "${GENERATOR_INSTANCE}/buildTools/")' in toolchain
+    assert 'set(FOO 42.2)' in toolchain
+    assert 'set(DICT 1)' in toolchain
+    assert 'set(CACHE_VAR "hello world" CACHE BOOL "test variable")' in toolchain
+
+
+    client.run(textwrap.dedent("""
+        install . -c tools.cmake.cmaketoolchain:extra_variables="{'invalid': {'value': 'hello world', 'cache': 'true'}}"
+    """) , assert_error=True)
+    assert 'tools.cmake.cmaketoolchain:extra_variables "cache" must be a boolean (True/False)' in client.out
+
+    # Test invalid cache variable
+    client.run(textwrap.dedent("""
+        install . -c tools.cmake.cmaketoolchain:extra_variables="{'invalid': {'value': 'hello world', 'cache': True}}"
+    """) , assert_error=True)
+    assert 'tools.cmake.cmaketoolchain:extra_variables needs "type" defined for cache variable "invalid"' in client.out
+
+    client.run(textwrap.dedent("""
+        install . -c tools.cmake.cmaketoolchain:extra_variables="{'invalid': {'value': 'hello world', 'cache': True, 'type': 'INVALID_TYPE'}}"
+    """) , assert_error=True)
+    assert 'tools.cmake.cmaketoolchain:extra_variables invalid type "INVALID_TYPE" for cache variable "invalid". Possible types: BOOL, FILEPATH, PATH, STRING, INTERNAL' in client.out
+
+    client.run(textwrap.dedent("""
+        install . -c tools.cmake.cmaketoolchain:extra_variables="{'CACHE_VAR_DEFAULT_DOC': {'value': 'hello world', 'cache': True, 'type': 'PATH'}}"
+    """))
+    toolchain = client.load("conan_toolchain.cmake")
+    assert 'set(CACHE_VAR_DEFAULT_DOC "hello world" CACHE PATH "CACHE_VAR_DEFAULT_DOC")' in toolchain
+