Python 3 support

[zackw]

Please consider these changes, which collectively add Python 3 support. The bulk of the work is modernizing CAPI use to the >=2.6 standard; the only Py3-specific changes are related to str/unicode and the different signature for module initialization.

[oschwald]

Thanks for the patch. Beyond just adding Python 3 support, it looks like a worthwhile clean-up of the code. Before merging, we need to discuss internally whether we are ready to drop Python 2.5 support, but I suspect that we are.

[zackw]

2.6 is the oldest Python I can conveniently test, but I suspect 2.5 will
either still work, or require only trivial changes. Most of the "new" stuff
I used is documented as present since the object revamp in 2.2.

If you do still need 2.5 internally and my changes don't work as is, I can
try to find time to set up a 2.5 environment and fix it, but I can't
promise any timeframe.

[oschwald]

I just tried building it on 2.5 using pyenv and received the following:

/usr/bin/gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/greg/.pyenv/versions/2.5.6/include/python2.5 -c py_GeoIP.c -o build/temp.linux-x86_64-2.5/py_GeoIP.o
py_GeoIP.c:662:5: warning: implicit declaration of function ‘PyVarObject_HEAD_INIT’ [-Wimplicit-function-declaration]
     PyVarObject_HEAD_INIT(NULL, 0)
     ^
py_GeoIP.c:663:5: error: initializer element is not constant
     "GeoIP.GeoIP",               /*tp_name*/
     ^
py_GeoIP.c:663:5: error: (near initialization for ‘GeoIP_GeoIPType.ob_refcnt’)
py_GeoIP.c:663:5: error: expected ‘}’ before string constant
py_GeoIP.c: In function ‘GeoIP_populate_module’:
py_GeoIP.c:762:5: warning: implicit declaration of function ‘PyModule_AddIntMacro’ [-Wimplicit-function-declaration]
     CHECK(PyModule_AddIntMacro(m, GEOIP_STANDARD));
     ^
py_GeoIP.c: At top level:
py_GeoIP.c:47:1: warning: ‘GeoIP_GeoIP_init’ defined but not used [-Wunused-function]
 GeoIP_GeoIP_init(PyObject *self, PyObject *args, PyObject *kwargs)
 ^
py_GeoIP.c:79:13: warning: ‘GeoIP_GeoIP_dealloc’ defined but not used [-Wunused-function]
 static void GeoIP_GeoIP_dealloc(PyObject *self)
             ^
py_GeoIP.c:565:20: warning: ‘GeoIP_GeoIP_methods’ defined but not used [-Wunused-variable]
 static PyMethodDef GeoIP_GeoIP_methods[] = {
                    ^
py_GeoIP.c:651:20: warning: ‘GeoIP_GeoIP_getsets’ defined but not used [-Wunused-variable]
 static PyGetSetDef GeoIP_GeoIP_getsets[] = {
                    ^
error: command '/usr/bin/gcc' failed with exit status 1

[oschwald]

I got some free time to look into that failure and fixed it in the branch greg/py3. We will review the rest of the changes and hopefully merge this.

[zackw]

Thanks for the pointer to pyenv; that makes backward compatibility testing much much easier.

I just pushed another batch of changes which should fix the py2.5 failures and also the CI failures (all of the CI failures appear to be because of -Wmissing-field-initializers, which is not in any of my pythons' default CFLAGS). Now works for me with 2.5, 2.6, 2.7, 3.3, and 3.4.

[oschwald]

Everything looks great. Thanks! 👍

[oschwald]

I released this to PyPI.

[zackw]

Awesome! Thanks for the quick turnaround.

[oschwald]

I realized that non-ascii strings were broken in Python 3 with these changes as they are encoded in Latin1 by default. I fixed this in #13 and will release that once someone here reviews it.