Confused about CMAKE_ARGS / SKBUILD_CMAKE_ARGS

[haampie]

I don't find the docs very helpful w.r.t. CMAKE_ARGS / SKBUILD_CMAKE_ARGS, so I'm grepping through the sources.

I found a test that sets SKBUILD_CMAKE_ARGS as follows:

monkeypatch.setenv("SKBUILD_CMAKE_ARGS", "-DFOO=BAR;-DBAR=FOO")

which gets parsed as

assert settings.cmake.args == ["-DFOO=BAR", "-DBAR=FOO"]

but this looks wrong to me, cause ; is a list separator in CMake. If you pass cmake '-DFOO=BAR;-DBAR=FOO' on the command line, CMake defines FOO as the list ["BAR", "-DBAR=FOO"].

Further, in scikit-build the value of CMAKE_ARGS was parsed using shlex.split, which is necessary to support white space in cmake arguments. When I grep for shlex.split in this code base, all I see is

scikit-build-core/src/scikit_build_core/builder/builder.py

Line 112 in bfbd625

filter(None, shlex.split(self.config.env.get("CMAKE_ARGS", "")))

which is apparently handled separately from SKBUILD_CMAKE_ARGS?

And SKBUILD_CMAKE_ARGS does use shlex.split?

1. How am I supposed to pass CMake defines that may contain whitespace in scikit-build-core?
2. What's the difference between SKBUILD_CMAKE_ARGS and CMAKE_ARGS?

[henryiii]

CMAKE_ARGS is modeled after conda-forge and other similar environments which work this way, with space separated values using shlex.split. SKBUILD_CMAKE_ARGS is identical to the other SKBUILD_* variables that can be used instead of passing --config-settings or setting the values in tool.scikit-build, and uses ; as the separator.

The best way to set a define is to use -Ccmake.define.FOO=BAR -Ccmake.define.BAR=FOO on the command line.

[haampie]

Ah, thanks. That is much better than this environment variable value parsing madness.

[haampie]

Closing this too early.

Is there a way to pass args in general, not just defines? Say -Ccmake.arg=--debug-find etc?

[henryiii]

It has an s. -Ccmake.args=1 -Ccmake.args=2, etc. It's literally the same thing as SKBUILD_CMAKE_ARGS, every argument can be passed in pyproject.toml, on the command line, or as an environment variable.

[haampie]

Thanks, will try