TST: don't use Py_ssize_t in the buffer for now

Author: wesm

pandas/core/groupby.py

@@ -1358,7 +1358,8 @@ def slicer(data, slob):
         def slicer(data, slob):
             return data[slob]
 
-    starts, ends = lib.generate_slices(group_index, np.prod(shape))
+    starts, ends = lib.generate_slices(group_index.astype('i4'),
+                                       np.prod(shape))
 
     for i, (start, end) in enumerate(zip(starts, ends)):
         if start == end:

pandas/src/groupby.pyx

@@ -513,7 +513,7 @@ def duplicated(list values, take_last=False):
     return result.view(np.bool_)
 
 
-def generate_slices(ndarray[Py_ssize_t] labels, Py_ssize_t ngroups):
+def generate_slices(ndarray[int32_t] labels, Py_ssize_t ngroups):
     cdef:
         Py_ssize_t i, group_size, n, lab, start
         object slobj