Problem with testing the last release in Python 3.9

[pllim]

pip install cubeviz downgrades pyqt5, causing this message to appear when mosviz is also installed: ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts. mosviz 0.3.1 requires pyqt5==5.12.3, but you have pyqt5 5.8 which is incompatible.

Running cubeviz command gave me this error in a clean conda env with Python 3.9 after I installed qt from conda. I failed to install PySide from both conda and pip; not sure why.

$ cubeviz
Traceback (most recent call last):
  File ".../python3.9/site-packages/qtpy/__init__.py", line 204, in <module>
    from PySide import __version__ as PYSIDE_VERSION  # analysis:ignore
ModuleNotFoundError: No module named 'PySide'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File ".../cubeviz", line 5, in <module>
    from cubeviz.cubeviz import main
  File ".../cubeviz/__init__.py", line 38, in <module>
    from . import keyboard_shortcuts
  File ".../cubeviz/keyboard_shortcuts.py", line 2, in <module>
    from qtpy import QtCore, QtWidgets, QtGui, compat
  File ".../qtpy/__init__.py", line 210, in <module>
    raise PythonQtError('No Qt bindings could be found')
qtpy.PythonQtError: No Qt bindings could be found

[pllim]

In Python 3.6, I still see the same "pip's dependency resolver..." message when mosviz is also installed, but the splash screen shows.

[ibusko]

The original JIRA ticket is JDAT-1296.

[eteq]

In some out-of-band discussion, I think we settled on the following solution:

• Set the maximum python version to whatever we know works right now (which I think is 3.6?)
• This has the downside that anyone who pip installs will get a downgrade
• ASAP, we put out a last version that has none of the current dependencies (and therefore leads to no downgrades), but just creates the error on import that says "go to jdaviz"

[pllim]

I see that there is a very specific pinning here:

https://github.com/spacetelescope/cubeviz/blob/c23e48113afa6ba4971bf483c4c50c9402383f0e/setup.cfg#L16

But I am not sure if it works because pip install cubeviz pulls in cubeviz 0.3.1 and specviz 0.7.0 into Python 3.9 env. 🤯

And the official doc has no example. 🤦 https://setuptools.readthedocs.io/en/latest/userguide/dependency_management.html#python-requirement "Example WIP"

[pllim]

Okay... now I am very confused... https://pypi.org/project/cubeviz/#history shows releases up to 0.3.3 but the tags on this repo only goes up to 0.3.0.

Actually... 0.3.2 is completely missing both in the repo and also on PyPI. 🤷

[pllim]

Regardless, now I don't quite see the value in releasing anything with max Python version pinning, as the resolver will just grab the last (and older) release without this pin for newer Python versions, which is even worse.

I will proceed to just lift the python_requires pin and gut this package out.