[vtk-developers] VTK, Python 3 and the six module - install error on six.pyc

[Marcus D. Hanwell]

On Tue, May 16, 2017 at 11:24 AM, Ben Boeckel <ben.boeckel at kitware.com> wrote:
> On Tue, May 16, 2017 at 11:11:50 -0400, Aron Helser wrote:
>> Yes, I updated Autobahn to use the third-party update mechanism, and used
>> the cmake files that already existed. I never tested the 'make install'
>> functionality
>> with Python 3. I would expect the ParaView superbuild to do that, but I
>> don't
>
> ParaView does other things for its Python install rules, so I'm not
> surprised that VTK on its own is a bit different. Maybe ParaView *only*
> installs the `.py` files and after installation does the `.pyc`
> generation?

I originally discovered this issue when doing a make install from
ParaView with the web stuff turned on using Python 3. Perhaps this
combination is not tested?
>
>> really know. I've not touched the vtk cmake infrastructure yet - I'll go
>> ask for help.
>> I don't see '__pycache__' handled anywhere in vtk/paraview .cmake files....
>
> That's the problem ;) . Python3 now stores `.pyc`, `.pyo`, and other
> files under a `__pycache__` directory rather than right beside the `.py`
> files they are generated from.
>
Yes, and the third party appears to be missing this. I found it in
building an updated ParaView dependency for Tomviz where we need
ParaView built against Python 3 and using the web flags in order to do
the export to a web viewer. If this isn't tested it would be nice to
get a test added.

I am out on travel right now, but can supply the flags for VTK and/or
ParaView. It is a VTK issue that ParaView seems to inherit when
turning on these modules recently ported to Python 3 (aside from the
make install step).