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

[Olly Betts]

Control: severity -1 normal

On Sat, Apr 07, 2018 at 05:30:19PM +0300, Adrian Bunk wrote:
> On Fri, Apr 06, 2018 at 11:53:39PM -0400, Scott Talbert wrote:
> > On Sat, 7 Apr 2018, Norbert Lange wrote:
> > 
> > > it appears that the files are installed in a subdirectory,
> > > potentially to avoid confligs with previous versions?
> > > result is that
> > > 
> > > import wx fails with
> > > 
> > > ImportError: No module named wx
> > > 
> > > I havent found a way to configure the installation
> > 
> > The purpose of the python-wxgtk4.0 package is primarily for application
> > developers to use in porting their applications to wxPython 4.0 (Phoenix).
> > There isn't much of a reason otherwise to use the Python 2 version of
> > wxPython 4.0.  Instead, you should use python3-wxgtk4.0 with which you can
> > 'import wx'.
> > 
> > If you really would like to use the Python 2 version, you can do:
> > 
> > PYTHONPATH=/usr/lib/python2.7/dist-packages/wxPython-4.0.1-py2.7-linux-amd64.egg python
> > import wx

This doesn't appear to be documented in the package, which it really
should be (probably a brief explanation in the package description, and
more detail in README.Debian).

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.

And a lot of packages use wxPython 3.0, so wxPython 4.0 for Python 2
really needs to be co-installable with wxPython 3.0.

Installing the module as "wx4" or something isn't helpful as that
doesn't match what upstream does, nor how it's packaged for Python 3.

The only reason Scott created this package is to help people maintaining
a wxPython application who want to migrate it to wxPython 4.0 - that
involves both porting it from Python 2 to Python 3 and from wxPython 3.0
to wxPython 4.0.  Rather than having to do both together, with this
package you can port to Python 2 + wxPython 4.0 as an intermediate step.

So I'd say the bug here is really that this isn't clear from the current
packages.

> 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.

Cheers,
    Olly