[Debian-med-packaging] Bug#910284: r-cran-fastcluster does not build Python modules for all supported Python versions

[Gard Spreemann]

Source: r-cran-fastcluster
Version: 1.1.25-1
Severity: important

Dear Maintainer,

The package currently does not build its Python modules for all
supported Python versions. For example, on Buster, we currently have

 $ py3versions -s
 python3.7 python3.6

Using fastcluster with the supported version 3.7 fails:

 $ python3.7
 Python 3.7.0 (default, Jun 27 2018, 14:40:03) 
 [GCC 8.1.0] on linux
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import fastcluster
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "/usr/lib/python3/dist-packages/fastcluster.py", line 37, in <module>
     from _fastcluster import linkage_wrap, linkage_vector_wrap
 ModuleNotFoundError: No module named '_fastcluster'
 >>>

Loading with the current default Python 3 version (3.6) works as
intended.

Section 3.3 of the Python Policy says that module packages should
support the current Debian Python version, and more if possible.

Please consider building the Python module for all supported Python
versions.

Thanks.


 Best regards,
 Gard Spreemann

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.18.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled