[Freewx-maint] Bug#895083: Bug#895083: python-wxgtk4.0: module wx is not usable

[Scott Talbert]

On Sun, 8 Apr 2018, Norbert Lange wrote:

>> Maybe it's also worth including a trival wrapper script to set
>> PYTHONPATH suitably and then exec python.
>>
>>> Is there a good reason why you are making it harder than necessary to
>>> use python-wxgtk4.0 ?
>>
>> Because wxPython 3.0 already exists for Python 2 as module "wx".  But
>> wxPython 3.0 doesn't support Python 3 and never will, so there's no
>> other claimant for module "wx" for Python 3.
>>
>> wxPython 4.0 is pretty much a from-the-ground-up rebuild and isn't
>> completely compatible with wxPython 3.0, so switching "import wx" to use
>> that for Python 2 would not work out well.
>
> its not entirely incompatible either, as right now I only get deprecation
> warnings on code that was written for wxPython 3.0.

The code you're running must not use any of the changed APIs.  See here 
for some of the changes:
https://github.com/wxWidgets/Phoenix/blob/master/docs/classic_vs_phoenix.rst

>>> Python 2 is fully supported by Debian during the lifetime of buster,
>>> and there are various reasons why many users are stuck with Python 2
>>> for some more time.
>>
>> There are, but people sticking with Python 2 are really unlikely to want
>> to use wxPython 4.0.
>
> Sticking to Python2 is not the reason, no. The argument would be to
> use wxPython 4.0,
> and have it painlessly run on current systems and with packages
> that aren't yet ported to python3.
> without wxPython 4.0 on python2, you have to stick to wxPython 3.0,
> and either bet on upwards compatibility or test on both libraries.

There really isn't much of a reason to use wxPython 4.0 though, other than 
for Python 3 support.  That's really the only major enhancement over 
wxPython 3.0.  Both wxPython 3.0 and wxPython 4.0 are python bindings for 
wxWidgets 3.0.  wxPython 4.0 just has a slightly different API in some 
cases.

> Personally I would prefer a mutual-exlusive installation or
> an update-alternatives scheme as sym-linking the wx folder did work for me.

We can't break any existing wxPython 3.0 applications though.  I suppose 
we could do an update-alternatives scheme, but wxPython 3.0 would have the 
higher priority to avoid breaking any applications.  So, it would really 
only be useful if wxPython 4.0 was the only one installed.

Scott