check in interp_with_fill too

Author: Tom Augspurger

doc/source/release.rst

@@ -116,16 +116,13 @@ Bug Fixes
 - TimeGrouper has a more compatible API to the rest of the groupers (e.g. ``groups`` was missing) (:issue:`3881`)
 - Bug in ``pd.eval`` when parsing strings with possible tokens like ``'&'``
   (:issue:`6351`)
-<<<<<<< HEAD
 - Bug correctly handle placements of ``-inf`` in Panels when dividing by integer 0 (:issue:`6178`)
 - ``DataFrame.shift`` with ``axis=1`` was raising (:issue:`6371`)
 - Disabled clipboard tests until release time (run locally with ``nosetests -A disabled`` (:issue:`6048`).
 - Bug in ``DataFrame.replace()`` when passing a nested ``dict`` that contained
   keys not in the values to be replaced (:issue:`6342`)
 - Bug in take with duplicate columns not consolidated (:issue:`6240`)
-=======
 - Bug in interpolate changing dtypes (:issue:`6290`)
->>>>>>> 336b309... BUG: preserve dtypes in interpolate
 
 pandas 0.13.1
 -------------

pandas/core/internals.py

@@ -805,13 +805,25 @@ def interpolate(self, method='pad', axis=0, index=None,
                     values=None, inplace=False, limit=None,
                     fill_value=None, coerce=False, downcast=None, **kwargs):
 
+        def check_int_bool(self, inplace):
+            # Only FloatBlocks will contain NaNs.
+            # timedelta subclasses IntBlock
+            if (self.is_bool or self.is_integer) and not self.is_timedelta:
+                if inplace:
+                    return self
+                else:
+                    return self.copy()
+
         # a fill na type method
         try:
             m = com._clean_fill_method(method)
         except:
             m = None
 
         if m is not None:
+            r = check_int_bool(self, inplace)
+            if r is not None:
+                return r
             return self._interpolate_with_fill(method=m,
                                                axis=axis,
                                                inplace=inplace,
@@ -826,6 +838,9 @@ def interpolate(self, method='pad', axis=0, index=None,
             m = None
 
         if m is not None:
+            r = check_int_bool(self, inplace)
+            if r is not None:
+                return r
             return self._interpolate(method=m,
                                      index=index,
                                      values=values,