dont pass Series with DTI to SeriesGrouper

Author: jbrockmendel

pandas/core/groupby/ops.py

@@ -45,7 +45,14 @@
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame
 from pandas.core.groupby import base, grouper
-from pandas.core.indexes.api import Index, MultiIndex, RangeIndex, ensure_index
+from pandas.core.indexes.api import (
+    DatetimeIndex,
+    Index,
+    MultiIndex,
+    RangeIndex,
+    TimedeltaIndex,
+    ensure_index,
+)
 from pandas.core.series import Series
 from pandas.core.sorting import (
     compress_group_index,
@@ -616,7 +623,9 @@ def agg_series(self, obj: Series, func: F, *args, **kwargs):
             # TODO: can we get a performant workaround for EAs backed by ndarray?
             return self._aggregate_series_pure_python(obj, func)
 
-        elif obj.index._has_complex_internals or isinstance(obj.index, RangeIndex):
+        elif obj.index._has_complex_internals or isinstance(
+            obj.index, (RangeIndex, DatetimeIndex, TimedeltaIndex)
+        ):
             # Preempt TypeError in _aggregate_series_fast
             # exclude RangeIndex because patching it in libreduction would
             #  silently be incorrect