At the top of a build tree we configure inside the CMakeFiles directory
files such as "CMakeSystem.cmake" and "CMake<lang>Compiler.cmake" to
save information detected about the system and compilers in use. The
method of detection and the exact results store varies across CMake
versions as things improve. This leads to problems when loading files
configured by a different version of CMake. Previously we ignored such
existing files only if the major.minor part of the CMake version
component changed, and depended on the CMakeCache.txt to tell us the
last version of CMake that wrote the files. This led to problems if the
user deletes the CMakeCache.txt or we add required information to the
files in a patch-level release of CMake (still a "feature point" release
by modern CMake versioning convention).
Ensure that we always have version-consistent platform information files
by storing them in a subdirectory named with the CMake version. Every
version of CMake will do its own system and compiler identification
checks even when a build tree has already been configured by another
version of CMake. Stored results will not clobber those from other
versions of CMake which may be run again on the same tree in the future.
Loaded results will match what the system and language modules expect.
Rename the undocumented variable CMAKE_PLATFORM_ROOT_BIN to
CMAKE_PLATFORM_INFO_DIR to clarify its purpose. The new variable points
at the version-specific directory while the old variable did not.
If you think about adding a new testcase then here is a small checklist you
can run through to find a proper place for it. Go through the list from the
beginning and stop once you find something that matches your tests needs,
i.e. if you will test a module and only need the configure mode use the
instructions from section 2, not 3.
1. Your testcase can run in CMake script mode, i.e. "cmake -P something"
Put your test in Tests/CMakeTests/ directory as a .cmake.in file. It will be
put into the test binary directory by configure_file(... @ONLY) and run from
there. Use the AddCMakeTest() macro in Tests/CMakeTests/CMakeLists.txt to add
your test to the test runs.
2. Your test needs CMake to run in configure mode, but will not build anything
This includes tests that will build something using try_compile() and friends,
but nothing that expects add_executable(), add_library(), or add_test() to run.
If the test configures the project only once and it must succeed then put it
into the Tests/CMakeOnly/ directory. Create a subdirectory named like your
test and write the CMakeLists.txt you need into that subdirectory. Use the
add_CMakeOnly_test() macro from Tests/CMakeOnly/CMakeLists.txt to add your
test to the test runs.
If the test configures the project with multiple variations and verifies
success or failure each time then put it into the Tests/RunCMake/ directory.
Read the instructions in Tests/RunCMake/CMakeLists.txt to add a test.
3. If you are testing something from the Modules directory
Put your test in the Tests/Modules/ directory. Create a subdirectory there
named after your test. Use the ADD_TEST_MACRO macro from Tests/CMakeLists.txt
to add your test to the test run. If you have put your stuff in
Tests/Modules/Foo then you call it using ADD_TEST_MACRO(Module.Foo Foo).
4. You are doing other stuff.
Find a good place ;) In doubt mail to cmake-developers@cmake.org and ask for
advise.
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