TypeError: Backend.__init__() takes 17 positional arguments but 18 were given

[yurivict]

Build fails:

===>  Building for py311-qmllib-1.1.5
* Getting build dependencies for wheel...
Using numpy 1.26.4
export FFLAGS='-O3 -fopenmp -m64 -march=native -fPIC -Wno-maybe-uninitialized -Wno-unused-function -Wno-cpp'
export LDFLAGS='-lgomp -lpthread -lm -ldl -L/usr/lib/ -lblas -llapack'
export FCC='gfortran'
src/qmllib/representations /usr/local/bin/python3.11 -m numpy.f2py -c frepresentations.f90 -m frepresentations --backend meson
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/usr/local/lib/python3.11/site-packages/numpy/f2py/__main__.py", line 5, in <module>
    main()
  File "/usr/local/lib/python3.11/site-packages/numpy/f2py/f2py2e.py", line 768, in main
    run_compile()
  File "/usr/local/lib/python3.11/site-packages/numpy/f2py/f2py2e.py", line 720, in run_compile
    builder = build_backend(
              ^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/numpy/f2py/_backends/_meson.py", line 123, in __init__
    super().__init__(*args, **kwargs)
TypeError: Backend.__init__() takes 17 positional arguments but 18 were given

Version: 1.1.5
Python-3.11
FreeBSD 14.2

[charnley]

Can you try with numpy > 2.0?

[yurivict]

Unfortunately numpy-2.0 is still not available on my platform.

[charnley]

When trying to build and run tests with Python 3.11 and numpy 1.26. I had no problems.

Using python 3.11.11
Using numpy 1.26.4
export FFLAGS='-O3 -m64 -march=native -fPIC -Wno-maybe-uninitialized -Wno-unused-function -Wno-cpp -fopenmp'
export LDFLAGS='-lpthread -lm -ldl -L/usr/lib/ -lblas -llapack -lgomp'
export FC='gfortran'
src/qmllib/representations /tmp/build-env-jjmrl44v/bin/python -m numpy.f2py -c frepresentations.f90 -m frepresentations --backend meson
...

What meson version do you have? Otherwise, I would need to run a docker with FreeBSD 14.2 to debug it.

[yurivict]

I used meson-1.6.1 and gcc13-13.3.0

---

FreeBSD doesn't run in Docker.
It can be installed into a VM:

Is there an easy way to test under FreeBSD?

1. Install the FreeBSD VM image into VirtualBox.
2. Boot FreeBSD
3. Install git: pkg install git

[charnley]

Can you tell me exactly which packages you installed in FreeBSD 14.2? I assume pkg install python3?

[yurivict]

gcc13, binutils, py311-build, py311-installer
python311, py311-numpy, py311-scipy

[charnley]

I could reproduce your error. I got the same error message, indicating something was wrong with the meson vs. Backend building classes in Numpy. Locally on Ubuntu, though, it worked fine for me.

And then it took me down a long rabid hole of trial and error. I am not sure why the changes I did to the qmllib package worked, but now I am not getting the error message. I also added some changes to the compile flags to find the math libs on FreeBSD. In the end this worked.

pkg install python311 py311-numpy py311-scipy py311-pip py311-build
pkg install gcc math/lapack math/blas
python3.11 -m pip install qmllib # 1.1.9

I could also get numpy 2.0 by

python3.11 -m pip install numpy --upgrade

[yurivict]

I am still getting the same error with the version 1.1.9 with numpy-1.26.4

numpy-2.x wasn't released as a package yet on FreeBSD because it causes breakage in a lot of various packages.

[charnley]

I restarted my FreeBSD with pkg delete -af and then rm -rf /usr/local/* and installed the dependencies. It still worked.

So, I need to find another time slot to reinstall the VM from scratch. Unfortunately, downloading build dependencies takes a long time, so iterations are slow.

Exactly which command did you use to install qmllib?

python -m pip install qmllib 

or

python -m pip install qmllib --user

My assumption is that when I installed Numpy 2.0 or another package, some dependencies corrected themselves. The error you are getting is from the f2py/numpy Builder constructor.

In the meantime, can you do a full Python environment dump? That will give me a bit more to work with.

pip freeze

[charnley]

Hey @yurivict , I just tried with a fresh VM of FreeBSD 14.2 https://download.freebsd.org/ftp/releases/VM-IMAGES/14.2-RELEASE/amd64/Latest/ .vmdk. Changed the hard disk size. And only ran the following commands;

pkg install gcc math/lapack math/blas
pkg install python311 py311-numpy py311-scipy py311-pip py311-build
python3.11 -m pip install qmllib --user

That works fine. Can you try it in a fresh FreeBSD? If that works, can you give me a complete dump of the python3.11 -m freeze so I can reproduce your environment?