BUG: improper use of conditional compilation always resulted in PyUnicode_GET_SIZE

Author: mattip

pandas/lib.pyx

@@ -26,9 +26,9 @@ from cpython cimport (PyDict_New, PyDict_GetItem, PyDict_SetItem,
                       PyBytes_GET_SIZE,
                       PyUnicode_GET_SIZE)
 
-try:
+IF PY_MAJOR_VERSION == 2:
     from cpython cimport PyString_GET_SIZE
-except ImportError:
+ELSE:
     from cpython cimport PyUnicode_GET_SIZE as PyString_GET_SIZE
 
 cdef extern from "Python.h":

setup.py

@@ -149,6 +149,11 @@ def build_extensions(self):
 
                 with open(outfile, "w") as f:
                     f.write(pyxcontent)
+            # XXX used only in lib.pyx, assumes old_build_ext
+            if not self.cython_compile_time_env:
+                self.cython_compile_time_env = {}
+            major = sys.version_info.major
+            self.cython_compile_time_env['PY_MAJOR_VERSION'] = major
 
         numpy_incl = pkg_resources.resource_filename('numpy', 'core/include')