Fix issue pandas-dev#712 - pandas deprecation warning in chunkstore serializer (pandas-dev#713)

Author: bmoscon

CHANGES.md

@@ -2,6 +2,7 @@
 
 ### 1.74
   * Feature: #688 Remove Chunkstore check for issue #422
+  * Bugfix: #712 Pandas deprecation warning in chunkstore serializer
 
 ### 1.73 (2018-11-27)
   * Bugfix: #658 Write/append errors for Panel objects from older pandas versions

arctic/serialization/numpy_arrays.py

@@ -74,15 +74,15 @@ def _convert_types(self, a):
         else:
             mask = None
 
-        if infer_dtype(a) == 'mixed':
+        if infer_dtype(a, skipna=False) == 'mixed':
             # assume its a string, otherwise raise an error
             try:
                 a = np.array([s.encode('ascii') for s in a])
                 a = a.astype('O')
             except:
                 raise ValueError("Column of type 'mixed' cannot be converted to string")
 
-        type_ = infer_dtype(a)
+        type_ = infer_dtype(a, skipna=False)
         if type_ in ['unicode', 'string']:
             max_len = max_len_string_array(a)
             return a.astype('U{:d}'.format(max_len)), mask
@@ -115,7 +115,7 @@ def docify(self, df):
                     masks[str(c)] = Binary(compress(mask.tostring()))
                 arrays.append(arr.tostring())
             except Exception as e:
-                typ = infer_dtype(df[c])
+                typ = infer_dtype(df[c], skipna=False)
                 msg = "Column '{}' type is {}".format(str(c), typ)
                 logging.info(msg)
                 raise e