Revert "ERR: Raise NotImplementedError with BaseIndexer and certain rolling operations (pandas-dev#33057)"

This reverts commit 2bf54a8.

Author: AlexKirko

pandas/core/window/common.py

@@ -324,27 +324,3 @@ def func(arg, window, min_periods=None):
         return cfunc(arg, window, min_periods)
 
     return func
-
-
-def validate_baseindexer_support(func_name: Optional[str]) -> None:
-    # GH 32865: These functions work correctly with a BaseIndexer subclass
-    BASEINDEXER_WHITELIST = {
-        "count",
-        "min",
-        "max",
-        "mean",
-        "sum",
-        "median",
-        "std",
-        "var",
-        "skew",
-        "kurt",
-        "quantile",
-        "cov",
-        "corr",
-    }
-    if isinstance(func_name, str) and func_name not in BASEINDEXER_WHITELIST:
-        raise NotImplementedError(
-            f"{func_name} is not supported with using a BaseIndexer "
-            f"subclasses. You can use .apply() with {func_name}."
-        )

pandas/core/window/rolling.py

@@ -48,7 +48,6 @@
     calculate_center_offset,
     calculate_min_periods,
     get_weighted_roll_func,
-    validate_baseindexer_support,
     zsqrt,
 )
 from pandas.core.window.indexers import (
@@ -393,12 +392,11 @@ def _get_cython_func_type(self, func: str) -> Callable:
             return self._get_roll_func(f"{func}_variable")
         return partial(self._get_roll_func(f"{func}_fixed"), win=self._get_window())
 
-    def _get_window_indexer(self, window: int, func_name: Optional[str]) -> BaseIndexer:
+    def _get_window_indexer(self, window: int) -> BaseIndexer:
         """
         Return an indexer class that will compute the window start and end bounds
         """
         if isinstance(self.window, BaseIndexer):
-            validate_baseindexer_support(func_name)
             return self.window
         if self.is_freq_type:
             return VariableWindowIndexer(index_array=self._on.asi8, window_size=window)
@@ -444,7 +442,7 @@ def _apply(
 
         blocks, obj = self._create_blocks()
         block_list = list(blocks)
-        window_indexer = self._get_window_indexer(window, name)
+        window_indexer = self._get_window_indexer(window)
 
         results = []
         exclude: List[Scalar] = []
@@ -1632,9 +1630,6 @@ def quantile(self, quantile, interpolation="linear", **kwargs):
     """
 
     def cov(self, other=None, pairwise=None, ddof=1, **kwargs):
-        if isinstance(self.window, BaseIndexer):
-            validate_baseindexer_support("cov")
-
         if other is None:
             other = self._selected_obj
             # only default unset
@@ -1781,9 +1776,6 @@ def _get_cov(X, Y):
     )
 
     def corr(self, other=None, pairwise=None, **kwargs):
-        if isinstance(self.window, BaseIndexer):
-            validate_baseindexer_support("corr")
-
         if other is None:
             other = self._selected_obj
             # only default unset

pandas/tests/window/test_base_indexer.py

@@ -82,19 +82,6 @@ def get_window_bounds(self, num_values, min_periods, center, closed):
         df.rolling(indexer, win_type="boxcar")
 
 
-@pytest.mark.parametrize("func", [])
-def test_notimplemented_functions(func):
-    # GH 32865
-    class CustomIndexer(BaseIndexer):
-        def get_window_bounds(self, num_values, min_periods, center, closed):
-            return np.array([0, 1]), np.array([1, 2])
-
-    df = DataFrame({"values": range(2)})
-    indexer = CustomIndexer()
-    with pytest.raises(NotImplementedError, match=f"{func} is not supported"):
-        getattr(df.rolling(indexer), func)()
-
-
 @pytest.mark.parametrize("constructor", [Series, DataFrame])
 @pytest.mark.parametrize(
     "func,np_func,expected,np_kwargs",