Compilation failures --python=39 or 310

[luc-j-bourhis]

In an empty directory, python .\boostrap.py --builder cctbx --python=39 --use-conda --nproc 10 fails with

...\modules\boost\libs\python\src\numpy\dtype.cpp(101): error C2039: 'elsize': is not a member of '_PyArray_Descr'
...\conda_base\lib\site-packages\numpy\_core\include\numpy\ndarraytypes.h(618): note: see declaration of '_PyArray_Descr'

With --python=310, it's

...\modules\boost\libs\python\src\exec.cpp(109): error C3861: '_Py_fopen': identifier not found

This was with Visual Studio 2022 but it is not relevant I don't think: the problem is that the version of Boost at https://github.com/cctbx/boost.git is far too old.

What am I missing here?!?

[bkpoon]

Sorry, I have not updated our copy of Boost yet since with the latest conda environments, we should move towards using the Boost headers and libraries inside the conda environment (currently at Boost 1.86).

There are 2 issues, the first one is a numpy 2.0 issue. The latest conda environments contain numpy 2 and our copy of Boost does not have the patches for numpy 2.0 support.

Numpy 2 change
https://numpy.org/devdocs/numpy_2_0_migration_guide.html#the-pyarray-descr-struct-has-been-changed

Boost patch (1.84 and 1.86 branches)
cctbx/boost@6c378eb

The second issue is also patched in later version of Boost (1.74 branch)

cctbx/boost@0a13aaa

I think for the cctbx builder, I will just change it so that bootstrap.py no longer pulls in our copy of Boost. For now, you can delete the modules/boost directory and add the --no-boost-src flag to your bootstrap command. That flag prevents the download of our Boost source. The reason we still have the boost directory is for compiling for older linux distributions with older versions of GCC.