python
Feature: Add guide to install system dependencies with pixi
Describe the enhancement or feature you would like
I've stopped using brew on my macOS and I'm instead using pixi whenever I need system-level dependencies. This works very well in practice even for building CPython and I can do things like pixi run configure and it automatically sets up all of the system dependencies and runs configure. Doing that requires setting some environment variables here and there, but I've done that in a pixi.toml and it's all automated. It looks somewhat like this:
[project]
name = "cpython-dev"
channels = ["conda-forge"]
platforms = ["osx-arm64"]
[dependencies]
gdbm = "*"
libmpdec-devel = "*"
openssl = "3.*"
pkg-config = "*"
tk = "*"
xz = "*"
zstd = "*"
zlib = "*"
[tasks.configure]
cmd = "./configure --with-openssl=$CONDA_PREFIX"
[tasks.configure.env]
PKG_CONFIG_PATH = "$CONDA_PREFIX/lib/pkgconfig"
GDBM_CFLAGS = "-I$CONDA_PREFIX/include"
GDBM_LIBS = "-L$CONDA_PREFIX/lib -lgdbm"
TCLTK_CFLAGS = "$(pkg-config --cflags tcl tk)"
# tcl.pc and tk.pc files contain stub libraries, but those do not extist
# in the conda package
TCLTK_LIBS = "$(pkg-config --libs tcl tk | sed 's/-l[^ ]*stub[^ ]*//g')"
LDFLAGS = "-Wl,-rpath,$CONDA_PREFIX/lib"
It's a bit too much to propose adding this to the CPython repo, at least for now. However, pointing to this as a way to install system-level dependencies in the devguide doesn't sounds like a bad idea to me.
Thoughts? Is there an appetite for this? If so, I can start drafting a PR.
Describe alternatives you have considered
No response
Additional context
No response
Is there an appetite for this?
While I have never used a Mac properly, this seems reasonable to me. Adding a third tab (we already have "Homebrew" and "MacPorts" seems fine.
It would be nice to also add other tasks with "usual" configuration options like debug build or a prefix. As far as I am aware, I think pixi tasks can accept user arguments. My typical python configuration/building is something like this
PYTHON_VERSION="3.14.0"
PYTHON_MINOR=$(echo $PYTHON_VERSION | grep -oE '^[0-9]+\.[0-9]+')
./configure --prefix=/opt/python/${PYTHON_VERSION}/ --enable-loadable-sqlite-extensions --with-openssl=/opt/homebrew/opt/openssl@3 --with-pydebug
sudo make -j16
sudo make altinstall
FWIW, we've found pixi extremely useful to test downstreams with the address sanitizer, as they need quite a delicate environment to be setup. I have proposed adding pixi definitions in CPython for ASAN builds at https://github.com/python/cpython/issues/142466, as IMO there's a strong reason to do so in that use-case.
I think a broader use of pixi could be helpful.
see https://github.com/python/cpython/pull/142469. That PR is geared towards automating builds which can be used downstream, but it should be helpful for similar work towards a Pixi workspace for developing CPython itself.
