add CMakeLists options to disable building CLI, installing headers

[jameslamb]

Contributes to #5061.

Proposes adding 3 options to CMakeLists.txt:

• __BUILD_FOR_PYTHON = indicate that lib_lightgbm is being built for use in a Python wheel
• BUILD_CLI = do / do not compile the lightgbm CLI when running make or make install
• INSTALL_HEADERS = do/do not move LightGBM's headers into CMAKE_INSTALL_PREFIX (e.g. /usr/local/include/LightGBM/*.h)

Benefits of this change

Prevents unnecessary compilation of the CLI when building the Python package with scikit-build-core.

Prevents unnecessary generation of Makefile code for targets that won't ever be used by the R and Python packages.

More Details

LightGBM's CMakeLists.txt generates Makefile(s) where make / make install has 3 effects:

• compile lib_lightgbm.{dll/so} + install it
• compile lightgbm (the CLI) + install it
• install LightGBM's header files to the default system location for headers

When building for the R and Python packages, the steps about the CLI and installing headers aren't required. LightGBM currently avoids those in those contexts by running make _lightgbm instead of make or make install.

LightGBM/python-package/setup.py

Line 174 in 1c873af

silent_call(["make", "_lightgbm", f"-I{build_dir}", "-j4"], raise_error=True,

LightGBM/R-package/src/install.libs.R

Line 138 in 1c873af

build_args <- c("_lightgbm", make_args_from_build_script)

To address #5061, in #5759 I'm proposing that LightGBM use scikit-build-core (https://github.com/scikit-build/scikit-build-core) as its build backend.

As of this writing, that project unconditionally runs make install on the CMake-generated makefiles (docs link). With that tool, there's no way to say "just build the _lightgbm target".

This PR's changes make it possible to use LightGBM's CMakeLists.txt in a way that make and make install only build the shared library.

[jameslamb]

The changes here in test.sh aren't strictly related to the CMakeLists.txt changes.

This isn't actually event changing anything about this script. Just breaking these arguments onto individual lines, to make the size of the diff in #5759 a bit smaller (and therefore those changes a bit easier to review).

[jameslamb]

Note that the new options BUILD_CLI and INSTALL_HEADERS both default to ON so that this PR preserves the current default behavior on master.

[jameslamb]

@guolinke @shiyu1994 can you please help with reviews on this and #5884 ? So I can hopefully continue making progress on #5061.

[jameslamb]

Thank you!

[github-actions]

This pull request has been automatically locked since there has not been any recent activity since it was closed. To start a new related discussion, open a new issue at https://github.com/microsoft/LightGBM/issues including a reference to this.