Fix python3 pyspatialite import

[dmarteau]

pyspatialite is broken under python 3.5+:

• The entry point of the c module does does not follow the python 3 specs - see https://docs.python.org/3/extending/building.html - and pyspatialite import fails with the following error:

ImportError: dynamic module does not define module export function (PyInit__spatialite)

• buffer() is removed in python3 in favor of memoryview - see https://docs.python.org/2/c-api/buffer.html. memoryview works in 2.7 and support the object implementing buffer protocol. I did not see any explicit reference to buffer() in the qgis ( buffer is aliased as Binary in dbapi2.py) but I cannot speak for plugins.

[mhugo]

Hi @dmarteau
Just to let you know pyspatialite is now replaced by sqlite + load_extension. See https://github.com/qgis/QGIS/blob/master/python/utils.py#L587
If your patch helps to simplify utils.spatialite_connect it's fine :)

[dmarteau]

Hi @mhugo,

Actually, this is going to be a problem on OSX: the default implementation for python module sqlite does not enable load_extension: mac users will have to use a patched versions of python sqlite which is a core module:

I don't know about homebrew but Macport currently adopt the OSX way - and I hope that is going to be fixed soon: https://trac.macports.org/ticket/49317.

David

[mhugo]

Ok, so on OSX with your patch and the compilation flag WITH_PYSPATIALITE, pyspatialite should now be usable in Python 3 ? Cool.
Does anyone know why we don't compile our own version of pyspatialite whatever the platform ?

[dmarteau]

Actually, this is really a pain to install pyspatialite on OSX because the official pyspatialite module is totally deprecated and the right way is to use load_extension from python (which is deactivated on OSX - it does not even compile). The actual QGIS implementation is 'de facto' the only way to use pyspatialite on OSX without patching python.

[m-kuhn]

No reason to check that, we no longer need to support python 2 on master

[jef-n]

This was a missing bit of 6e4e845.