How to force that CMAKE_TOOLCHAIN_FILE is an absolute file path?

Code
1

I use this code to check if the installed cmake config package is usable:

if(BEMAN_SCOPE_INSTALL_CONFIG_FILE_PACKAGE)
    # test if the targets are usable from the install directory
    add_test(
        NAME install-to-stagedir
        COMMAND
            ${CMAKE_COMMAND} --install ${CMAKE_BINARY_DIR} --prefix
            ${CMAKE_BINARY_DIR}/stagedir --config $<CONFIG>
    )
    add_test(
        NAME find-package-test
        COMMAND
            ${CMAKE_CTEST_COMMAND} # --verbose
            --output-on-failure -C $<CONFIG> --build-and-test
            "${CMAKE_SOURCE_DIR}/examples"
            "${CMAKE_CURRENT_BINARY_DIR}/find-package-test" --build-generator
            ${CMAKE_GENERATOR} --build-makeprogram ${CMAKE_MAKE_PROGRAM}
            --build-options #
            "-D BEMAN_SCOPE_IMPORT_STD=${BEMAN_SCOPE_IMPORT_STD}"
            "-D BEMAN_SCOPE_USE_DANIELA_ADVICE=${BEMAN_SCOPE_USE_DANIELA_ADVICE}"
            "-D BEMAN_USE_STD_MODULE=${BEMAN_USE_STD_MODULE}"
            "-D CMAKE_BUILD_TYPE=$<CONFIG>"
            "-D CMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
            "-D CMAKE_CXX_EXTENSIONS=${CMAKE_CXX_EXTENSIONS}"
            "-D CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}"
            "-D CMAKE_PREFIX_PATH=${CMAKE_BINARY_DIR}/stagedir"
            "-D CMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}"
    )
endif()

but sometimes the CMAKE_TOOLCHAIN_FILE is not an absolute file path?

2

For CMake ≤ 3.21:

See https://cmake.org/cmake/help/latest/manual/cmake.1.html#cmdoption-cmake-toolchain

and use the command cmake_path (if needed):

cmake_path(
    ABSOLUTE_PATH <relative_path>
    BASE_DIRECTORY <assumed_prefix>
    OUTPUT_VARIABLE <result_absolute_path>)
3

On CI it was a relative path, no idea why?

I am using CMake v4.3.3 both on CI and local.

But this changes helps:

diff --git a/CMakePresets.json b/CMakePresets.json
index b8ca3cc..085ddc9 100644
--- a/CMakePresets.json
+++ b/CMakePresets.json
@@ -16,7 +16,7 @@
         "CMAKE_EXPORT_COMPILE_COMMANDS": true,
         "CMAKE_INSTALL_MESSAGE": "LAZY",
         "CMAKE_SKIP_TEST_ALL_DEPENDENCY": false,
-        "CMAKE_PROJECT_TOP_LEVEL_INCLUDES": "infra/cmake/use-fetch-content.cmake"
+        "CMAKE_PROJECT_TOP_LEVEL_INCLUDES": "${sourceDir}/infra/cmake/use-fetch-content.cmake"
       }
     },
     {
@@ -53,7 +53,7 @@
         "_debug-base"
       ],
       "cacheVariables": {
-        "CMAKE_TOOLCHAIN_FILE": "infra/cmake/gnu-toolchain.cmake"
+        "CMAKE_TOOLCHAIN_FILE": "${sourceDir}/infra/cmake/gnu-toolchain.cmake"
       }
     },
     {