[Python-modules-team] Bug#896269: python3-rebulk: rebulk fails to import

[Helmut Grohne]

Package: python3-rebulk
Version: 0.9.0-1
Severity: serious
User: helmutg at debian.org
Usertags: python-import

After installing python3-rebulk importing the module rebulk
into a python interpreter fails with the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/rebulk/__init__.py", line 7, in <module>
    from .rebulk import Rebulk
  File "/usr/lib/python3/dist-packages/rebulk/rebulk.py", line 13, in <module>
    from .processors import ConflictSolver, PrivateRemover
  File "/usr/lib/python3/dist-packages/rebulk/processors.py", line 10, in <module>
    from .rules import Rule, RemoveMatch
  File "/usr/lib/python3/dist-packages/rebulk/rules.py", line 14, in <module>
    from toposort import toposort
ModuleNotFoundError: No module named 'toposort'

The vast majority of import failures is attributed to missing dependencies.
Often times that manifests as an ImportError or ModuleNotFoundError.
Typically, dependencies should be inserted by dh-python via ${python:Depends}
or ${python3:Depends}. Thus a missing dependency can be caused by incomplete
install_requires in setup.py. Sometimes a missing dependency of a dependency
is the cause, in such cases this bug should be reassigned.

Helmut