From ba3d0f2d128c997069e4d83ca3adb0ca089df366 Mon Sep 17 00:00:00 2001
From: Tom Augspurger <tom.w.augspurger@gmail.com>
Date: Fri, 3 Apr 2020 10:09:21 -0500
Subject: [PATCH 1/3] Pass method in __finalize__

This passes `method` everywhere we use `__finalize__`. This will be
useful for future enhancements buliding on `__finalize__`.
---
 pandas/core/base.py          |  2 +-
 pandas/core/frame.py         | 10 ++--
 pandas/core/generic.py       | 90 ++++++++++++++++++++++--------------
 pandas/core/indexes/multi.py |  2 +-
 pandas/core/ops/__init__.py  |  2 +-
 pandas/core/series.py        | 64 ++++++++++++++++---------
 6 files changed, 106 insertions(+), 64 deletions(-)

diff --git a/pandas/core/base.py b/pandas/core/base.py
index a28a2c9594341..5945d8a4b432d 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -1521,4 +1521,4 @@ def duplicated(self, keep="first"):
         else:
             return self._constructor(
                 duplicated(self, keep=keep), index=self.index
-            ).__finalize__(self)
+            ).__finalize__(self, method="duplicated")
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index be04bbc7942c4..94ec49c5b1b2a 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2521,7 +2521,7 @@ def transpose(self, *args, copy: bool = False) -> "DataFrame":
                 new_values, index=self.columns, columns=self.index
             )
 
-        return result.__finalize__(self)
+        return result.__finalize__(self, method="transpose")
 
     @property
     def T(self) -> "DataFrame":
@@ -2662,7 +2662,7 @@ def _getitem_multilevel(self, key):
                 result = self._constructor(
                     new_values, index=self.index, columns=result_columns
                 )
-                result = result.__finalize__(self)
+                result = result.__finalize__(self, method="_getitem_multilevel")
 
             # If there is only one column being returned, and its name is
             # either an empty string, or a tuple with an empty string as its
@@ -4480,7 +4480,7 @@ def _maybe_casted_values(index, labels=None):
     @Appender(_shared_docs["isna"] % _shared_doc_kwargs)
     def isna(self) -> "DataFrame":
         result = self._constructor(self._data.isna(func=isna))
-        return result.__finalize__(self)
+        return result.__finalize__(self, method="isna")
 
     @Appender(_shared_docs["isna"] % _shared_doc_kwargs)
     def isnull(self) -> "DataFrame":
@@ -4808,7 +4808,7 @@ def sort_values(
         if inplace:
             return self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="sort_values")
 
     def sort_index(
         self,
@@ -4944,7 +4944,7 @@ def sort_index(
         if inplace:
             return self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="sort_index")
 
     def value_counts(
         self,
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 143e4543e7ab8..6dabd7047d30a 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -144,7 +144,9 @@ def _single_replace(self, to_replace, method, inplace, limit):
     if values.dtype == orig_dtype and inplace:
         return
 
-    result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(self)
+    result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(
+        self, method="_single_replace"
+    )
 
     if inplace:
         self._update_inplace(result)
@@ -588,7 +590,9 @@ def swapaxes(self: FrameOrSeries, axis1, axis2, copy=True) -> FrameOrSeries:
         if copy:
             new_values = new_values.copy()
 
-        return self._constructor(new_values, *new_axes).__finalize__(self)
+        return self._constructor(new_values, *new_axes).__finalize__(
+            self, method="swapaxes"
+        )
 
     def droplevel(self: FrameOrSeries, level, axis=0) -> FrameOrSeries:
         """
@@ -991,7 +995,7 @@ def rename(
             self._update_inplace(result)
             return None
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="rename")
 
     @rewrite_axis_style_signature("mapper", [("copy", True), ("inplace", False)])
     def rename_axis(self, mapper=lib.no_default, **kwargs):
@@ -1357,7 +1361,7 @@ def __invert__(self):
             return self
 
         new_data = self._data.apply(operator.invert)
-        result = self._constructor(new_data).__finalize__(self)
+        result = self._constructor(new_data).__finalize__(self, method="__invert__")
         return result
 
     def __nonzero__(self):
@@ -1802,7 +1806,9 @@ def __array_wrap__(self, result, context=None):
             # ptp also requires the item_from_zerodim
             return result
         d = self._construct_axes_dict(self._AXIS_ORDERS, copy=False)
-        return self._constructor(result, **d).__finalize__(self)
+        return self._constructor(result, **d).__finalize__(
+            self, method="__array_wrap__"
+        )
 
     # ideally we would define this to avoid the getattr checks, but
     # is slower
@@ -3360,7 +3366,7 @@ class  max_speed
         new_data = self._data.take(
             indices, axis=self._get_block_manager_axis(axis), verify=True
         )
-        return self._constructor(new_data).__finalize__(self)
+        return self._constructor(new_data).__finalize__(self, method="take")
 
     def _take_with_is_copy(self: FrameOrSeries, indices, axis=0) -> FrameOrSeries:
         """
@@ -3567,7 +3573,7 @@ def _slice(self: FrameOrSeries, slobj: slice, axis=0) -> FrameOrSeries:
         assert isinstance(slobj, slice), type(slobj)
         axis = self._get_block_manager_axis(axis)
         result = self._constructor(self._data.get_slice(slobj, axis=axis))
-        result = result.__finalize__(self)
+        result = result.__finalize__(self, method="_slice")
 
         # this could be a view
         # but only in a single-dtyped view sliceable case
@@ -4433,7 +4439,7 @@ def reindex(self: FrameOrSeries, *args, **kwargs) -> FrameOrSeries:
         # perform the reindex on the axes
         return self._reindex_axes(
             axes, level, limit, tolerance, method, fill_value, copy
-        ).__finalize__(self)
+        ).__finalize__(self, method="reindex")
 
     def _reindex_axes(
         self: FrameOrSeries, axes, level, limit, tolerance, method, fill_value, copy
@@ -4506,7 +4512,9 @@ def _reindex_with_indexers(
         if copy and new_data is self._data:
             new_data = new_data.copy()
 
-        return self._constructor(new_data).__finalize__(self)
+        return self._constructor(new_data).__finalize__(
+            self, method="_reindex_with_indexers"
+        )
 
     def filter(
         self: FrameOrSeries,
@@ -5132,7 +5140,7 @@ def pipe(self, func, *args, **kwargs):
     # Attribute access
 
     def __finalize__(
-        self: FrameOrSeries, other, method=None, **kwargs
+        self: FrameOrSeries, other, method: Optional[str] = None, **kwargs
     ) -> FrameOrSeries:
         """
         Propagate metadata from other to self.
@@ -5268,7 +5276,9 @@ def _consolidate(self, inplace: bool_t = False):
         else:
             f = lambda: self._data.consolidate()
             cons_data = self._protect_consolidate(f)
-            return self._constructor(cons_data).__finalize__(self)
+            return self._constructor(cons_data).__finalize__(
+                self, method="_consolidate"
+            )
 
     @property
     def _is_mixed_type(self) -> bool_t:
@@ -5297,10 +5307,14 @@ def _check_inplace_setting(self, value) -> bool_t:
         return True
 
     def _get_numeric_data(self):
-        return self._constructor(self._data.get_numeric_data()).__finalize__(self)
+        return self._constructor(self._data.get_numeric_data()).__finalize__(
+            self, method="_get_numeric_data"
+        )
 
     def _get_bool_data(self):
-        return self._constructor(self._data.get_bool_data()).__finalize__(self)
+        return self._constructor(self._data.get_bool_data()).__finalize__(
+            self, method="_get_bool_data"
+        )
 
     # ----------------------------------------------------------------------
     # Internal Interface Methods
@@ -5427,7 +5441,7 @@ def _to_dict_of_blocks(self, copy: bool_t = True):
         Internal ONLY
         """
         return {
-            k: self._constructor(v).__finalize__(self)
+            k: self._constructor(v).__finalize__(self, mehtod="_to_dict_of_blocks")
             for k, v, in self._data.to_dict(copy=copy).items()
         }
 
@@ -5567,7 +5581,7 @@ def astype(
         else:
             # else, only a single dtype is given
             new_data = self._data.astype(dtype=dtype, copy=copy, errors=errors)
-            return self._constructor(new_data).__finalize__(self)
+            return self._constructor(new_data).__finalize__(self, method="_astype")
 
         # GH 19920: retain column metadata after concat
         result = pd.concat(results, axis=1, copy=False)
@@ -5680,7 +5694,7 @@ def copy(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
         dtype: object
         """
         data = self._data.copy(deep=deep)
-        return self._constructor(data).__finalize__(self)
+        return self._constructor(data).__finalize__(self, method="copy")
 
     def __copy__(self: FrameOrSeries, deep: bool_t = True) -> FrameOrSeries:
         return self.copy(deep=deep)
@@ -5739,7 +5753,7 @@ def _convert(
                 coerce=coerce,
                 copy=copy,
             )
-        ).__finalize__(self)
+        ).__finalize__(self, method="_convert")
 
     def infer_objects(self: FrameOrSeries) -> FrameOrSeries:
         """
@@ -5788,7 +5802,7 @@ def infer_objects(self: FrameOrSeries) -> FrameOrSeries:
             self._data.convert(
                 datetime=True, numeric=False, timedelta=True, coerce=False, copy=True
             )
-        ).__finalize__(self)
+        ).__finalize__(self, method="infer_objects")
 
     def convert_dtypes(
         self: FrameOrSeries,
@@ -6115,7 +6129,7 @@ def fillna(
         if inplace:
             return self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="fillna")
 
     def ffill(
         self: FrameOrSeries,
@@ -6631,7 +6645,7 @@ def replace(
         if inplace:
             return self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="replace")
 
     _shared_docs[
         "interpolate"
@@ -6897,7 +6911,7 @@ def interpolate(
         if inplace:
             return self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="interpolate")
 
     # ----------------------------------------------------------------------
     # Timeseries methods Methods
@@ -7135,11 +7149,11 @@ def asof(self, where, subset=None):
 
     @Appender(_shared_docs["isna"] % _shared_doc_kwargs)
     def isna(self: FrameOrSeries) -> FrameOrSeries:
-        return isna(self).__finalize__(self)
+        return isna(self).__finalize__(self, method="isna")
 
     @Appender(_shared_docs["isna"] % _shared_doc_kwargs)
     def isnull(self: FrameOrSeries) -> FrameOrSeries:
-        return isna(self).__finalize__(self)
+        return isna(self).__finalize__(self, method="isnull")
 
     _shared_docs[
         "notna"
@@ -7205,11 +7219,11 @@ def isnull(self: FrameOrSeries) -> FrameOrSeries:
 
     @Appender(_shared_docs["notna"] % _shared_doc_kwargs)
     def notna(self: FrameOrSeries) -> FrameOrSeries:
-        return notna(self).__finalize__(self)
+        return notna(self).__finalize__(self, method="notna")
 
     @Appender(_shared_docs["notna"] % _shared_doc_kwargs)
     def notnull(self: FrameOrSeries) -> FrameOrSeries:
-        return notna(self).__finalize__(self)
+        return notna(self).__finalize__(self, method="notnull")
 
     def _clip_with_scalar(self, lower, upper, inplace: bool_t = False):
         if (lower is not None and np.any(isna(lower))) or (
@@ -8223,7 +8237,7 @@ def ranker(data):
                 pct=pct,
             )
             ranks = self._constructor(ranks, **data._construct_axes_dict())
-            return ranks.__finalize__(self)
+            return ranks.__finalize__(self, method="rank")
 
         # if numeric_only is None, and we can't get anything, we try with
         # numeric_only=True
@@ -8430,7 +8444,10 @@ def _align_frame(
                     left.index = join_index
                     right.index = join_index
 
-        return left.__finalize__(self), right.__finalize__(other)
+        return (
+            left.__finalize__(self, method="_align_frame"),
+            right.__finalize__(other, method="_align_frame"),
+        )
 
     def _align_series(
         self,
@@ -8514,7 +8531,10 @@ def _align_series(
                         left.index = join_index
                         right.index = join_index
 
-        return left.__finalize__(self), right.__finalize__(other)
+        return (
+            left.__finalize__(self, method="_align_series"),
+            right.__finalize__(other, method="_align_series"),
+        )
 
     def _where(
         self,
@@ -8655,7 +8675,7 @@ def _where(
                 axis=block_axis,
             )
             result = self._constructor(new_data)
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="_where")
 
     _shared_docs[
         "where"
@@ -8927,7 +8947,7 @@ def shift(
         else:
             return self.tshift(periods, freq)
 
-        return self._constructor(new_data).__finalize__(self)
+        return self._constructor(new_data).__finalize__(self, method="shift")
 
     def slice_shift(self: FrameOrSeries, periods: int = 1, axis=0) -> FrameOrSeries:
         """
@@ -8964,7 +8984,7 @@ def slice_shift(self: FrameOrSeries, periods: int = 1, axis=0) -> FrameOrSeries:
         shifted_axis = self._get_axis(axis)[islicer]
         new_obj.set_axis(shifted_axis, axis=axis, inplace=True)
 
-        return new_obj.__finalize__(self)
+        return new_obj.__finalize__(self, method="slice_shift")
 
     def tshift(
         self: FrameOrSeries, periods: int = 1, freq=None, axis: Axis = 0
@@ -9024,7 +9044,7 @@ def tshift(
 
         result = self.copy()
         result.set_axis(new_ax, axis, inplace=True)
-        return result.__finalize__(self)
+        return result.__finalize__(self, method="tshift")
 
     def truncate(
         self: FrameOrSeries, before=None, after=None, axis=None, copy: bool_t = True
@@ -9235,7 +9255,7 @@ def _tz_convert(ax, tz):
 
         result = self.copy(deep=copy)
         result = result.set_axis(ax, axis=axis, inplace=False)
-        return result.__finalize__(self)
+        return result.__finalize__(self, method="tz_convert")
 
     def tz_localize(
         self: FrameOrSeries,
@@ -9404,7 +9424,7 @@ def _tz_localize(ax, tz, ambiguous, nonexistent):
 
         result = self.copy(deep=copy)
         result = result.set_axis(ax, axis=axis, inplace=False)
-        return result.__finalize__(self)
+        return result.__finalize__(self, method="tz_localize")
 
     # ----------------------------------------------------------------------
     # Numeric Methods
@@ -11183,7 +11203,7 @@ def block_accum_func(blk_values):
 
         d = self._construct_axes_dict()
         d["copy"] = False
-        return self._constructor(result, **d).__finalize__(self)
+        return self._constructor(result, **d).__finalize__(self, method=name)
 
     return set_function_name(cum_func, name, cls)
 
diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index 10d62b522a255..512ec2666c56c 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -2342,7 +2342,7 @@ def _get_values_for_loc(self, series: "Series", loc, key):
         new_index = self[loc]
         new_index = maybe_droplevels(new_index, key)
         new_ser = series._constructor(new_values, index=new_index, name=series.name)
-        return new_ser.__finalize__(series)
+        return new_ser.__finalize__(series, method="_get_values_for_loc")
 
     def _convert_listlike_indexer(self, keyarr):
         """
diff --git a/pandas/core/ops/__init__.py b/pandas/core/ops/__init__.py
index 10dcb59977cdd..55833c8fa89b3 100644
--- a/pandas/core/ops/__init__.py
+++ b/pandas/core/ops/__init__.py
@@ -413,7 +413,7 @@ def _construct_result(
     # We do not pass dtype to ensure that the Series constructor
     #  does inference in the case where `result` has object-dtype.
     out = left._constructor(result, index=index)
-    out = out.__finalize__(left)
+    out = out.__finalize__(left, method="_construct_result")
 
     # Set the result's name after __finalize__ is called because __finalize__
     #  would set it back to self.name
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 03b82365358ac..9b2be63e61e1d 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -661,7 +661,7 @@ def view(self, dtype=None) -> "Series":
         """
         return self._constructor(
             self._values.view(dtype), index=self.index
-        ).__finalize__(self)
+        ).__finalize__(self, method="view")
 
     # ----------------------------------------------------------------------
     # NDArray Compat
@@ -829,7 +829,7 @@ def take(self, indices, axis=0, is_copy=None, **kwargs) -> "Series":
 
         return self._constructor(
             new_values, index=new_index, fastpath=True
-        ).__finalize__(self)
+        ).__finalize__(self, method="take")
 
     def _take_with_is_copy(self, indices, axis=0):
         """
@@ -962,12 +962,14 @@ def _get_values_tuple(self, key):
         # If key is contained, would have returned by now
         indexer, new_index = self.index.get_loc_level(key)
         return self._constructor(self._values[indexer], index=new_index).__finalize__(
-            self
+            self, method="_get_values_tuple",
         )
 
     def _get_values(self, indexer):
         try:
-            return self._constructor(self._data.get_slice(indexer)).__finalize__(self)
+            return self._constructor(self._data.get_slice(indexer)).__finalize__(
+                self, method="_get_values"
+            )
         except ValueError:
             # mpl compat if we look up e.g. ser[:, np.newaxis];
             #  see tests.series.timeseries.test_mpl_compat_hack
@@ -1181,7 +1183,9 @@ def repeat(self, repeats, axis=None) -> "Series":
         nv.validate_repeat(tuple(), dict(axis=axis))
         new_index = self.index.repeat(repeats)
         new_values = self._values.repeat(repeats)
-        return self._constructor(new_values, index=new_index).__finalize__(self)
+        return self._constructor(new_values, index=new_index).__finalize__(
+            self, method="repeat"
+        )
 
     def reset_index(self, level=None, drop=False, name=None, inplace=False):
         """
@@ -1308,7 +1312,7 @@ def reset_index(self, level=None, drop=False, name=None, inplace=False):
             else:
                 return self._constructor(
                     self._values.copy(), index=new_index
-                ).__finalize__(self)
+                ).__finalize__(self, method="reset_index")
         elif inplace:
             raise TypeError(
                 "Cannot reset_index inplace on a Series to create a DataFrame"
@@ -1709,7 +1713,9 @@ def count(self, level=None):
 
         obs = level_codes[notna(self._values)]
         out = np.bincount(obs, minlength=len(lev) or None)
-        return self._constructor(out, index=lev, dtype="int64").__finalize__(self)
+        return self._constructor(out, index=lev, dtype="int64").__finalize__(
+            self, method="count"
+        )
 
     def mode(self, dropna=True) -> "Series":
         """
@@ -2132,7 +2138,9 @@ def round(self, decimals=0, *args, **kwargs) -> "Series":
         """
         nv.validate_round(args, kwargs)
         result = self._values.round(decimals)
-        result = self._constructor(result, index=self.index).__finalize__(self)
+        result = self._constructor(result, index=self.index).__finalize__(
+            self, method="round"
+        )
 
         return result
 
@@ -2354,7 +2362,9 @@ def diff(self, periods: int = 1) -> "Series":
         dtype: float64
         """
         result = algorithms.diff(self.array, periods)
-        return self._constructor(result, index=self.index).__finalize__(self)
+        return self._constructor(result, index=self.index).__finalize__(
+            self, method="diff"
+        )
 
     def autocorr(self, lag=1) -> float:
         """
@@ -2471,7 +2481,7 @@ def dot(self, other):
         if isinstance(other, ABCDataFrame):
             return self._constructor(
                 np.dot(lvals, rvals), index=other.columns
-            ).__finalize__(self)
+            ).__finalize__(self, method="dot")
         elif isinstance(other, Series):
             return np.dot(lvals, rvals)
         elif isinstance(rvals, np.ndarray):
@@ -2996,7 +3006,7 @@ def _try_kind_sort(arr):
         if inplace:
             self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="sort_values")
 
     def sort_index(
         self,
@@ -3174,7 +3184,7 @@ def sort_index(
         if inplace:
             self._update_inplace(result)
         else:
-            return result.__finalize__(self)
+            return result.__finalize__(self, method="sort_index")
 
     def argsort(self, axis=0, kind="quicksort", order=None) -> "Series":
         """
@@ -3208,11 +3218,13 @@ def argsort(self, axis=0, kind="quicksort", order=None) -> "Series":
             result = Series(-1, index=self.index, name=self.name, dtype="int64")
             notmask = ~mask
             result[notmask] = np.argsort(values[notmask], kind=kind)
-            return self._constructor(result, index=self.index).__finalize__(self)
+            return self._constructor(result, index=self.index).__finalize__(
+                self, method="argsort"
+            )
         else:
             return self._constructor(
                 np.argsort(values, kind=kind), index=self.index, dtype="int64"
-            ).__finalize__(self)
+            ).__finalize__(self, method="argsort")
 
     def nlargest(self, n=5, keep="first") -> "Series":
         """
@@ -3430,7 +3442,7 @@ def swaplevel(self, i=-2, j=-1, copy=True) -> "Series":
         assert isinstance(self.index, ABCMultiIndex)
         new_index = self.index.swaplevel(i, j)
         return self._constructor(self._values, index=new_index, copy=copy).__finalize__(
-            self
+            self, method="swaplevel"
         )
 
     def reorder_levels(self, order) -> "Series":
@@ -3634,7 +3646,9 @@ def map(self, arg, na_action=None) -> "Series":
         dtype: object
         """
         new_values = super()._map_values(arg, na_action=na_action)
-        return self._constructor(new_values, index=self.index).__finalize__(self)
+        return self._constructor(new_values, index=self.index).__finalize__(
+            self, method="map"
+        )
 
     def _gotitem(self, key, ndim, subset=None) -> "Series":
         """
@@ -3821,7 +3835,7 @@ def apply(self, func, convert_dtype=True, args=(), **kwds):
         """
         if len(self) == 0:
             return self._constructor(dtype=self.dtype, index=self.index).__finalize__(
-                self
+                self, method="apply"
             )
 
         # dispatch to agg
@@ -3858,7 +3872,9 @@ def f(x):
             # so extension arrays can be used
             return self._constructor_expanddim(pd.array(mapped), index=self.index)
         else:
-            return self._constructor(mapped, index=self.index).__finalize__(self)
+            return self._constructor(mapped, index=self.index).__finalize__(
+                self, method="apply"
+            )
 
     def _reduce(
         self, op, name, axis=0, skipna=True, numeric_only=None, filter_type=None, **kwds
@@ -4303,7 +4319,9 @@ def isin(self, values) -> "Series":
         Name: animal, dtype: bool
         """
         result = algorithms.isin(self, values)
-        return self._constructor(result, index=self.index).__finalize__(self)
+        return self._constructor(result, index=self.index).__finalize__(
+            self, method="isin"
+        )
 
     def between(self, left, right, inclusive=True) -> "Series":
         """
@@ -4539,7 +4557,9 @@ def to_timestamp(self, freq=None, how="start", copy=True) -> "Series":
 
         assert isinstance(self.index, (ABCDatetimeIndex, ABCPeriodIndex))
         new_index = self.index.to_timestamp(freq=freq, how=how)
-        return self._constructor(new_values, index=new_index).__finalize__(self)
+        return self._constructor(new_values, index=new_index).__finalize__(
+            self, method="to_timestamp"
+        )
 
     def to_period(self, freq=None, copy=True) -> "Series":
         """
@@ -4564,7 +4584,9 @@ def to_period(self, freq=None, copy=True) -> "Series":
 
         assert isinstance(self.index, ABCDatetimeIndex)
         new_index = self.index.to_period(freq=freq)
-        return self._constructor(new_values, index=new_index).__finalize__(self)
+        return self._constructor(new_values, index=new_index).__finalize__(
+            self, method="to_period"
+        )
 
     # ----------------------------------------------------------------------
     # Add index

From 1a3220fa0a9b8e9e7c04b8c622e4467ec0da0e36 Mon Sep 17 00:00:00 2001
From: Tom Augspurger <tom.w.augspurger@gmail.com>
Date: Mon, 6 Apr 2020 07:33:46 -0500
Subject: [PATCH 2/3] note

---
 pandas/core/generic.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 6dabd7047d30a..c60d7a9590f88 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -5149,9 +5149,14 @@ def __finalize__(
         ----------
         other : the object from which to get the attributes that we are going
             to propagate
-        method : optional, a passed method name ; possibly to take different
-            types of propagation actions based on this
+        method : str, optional
+            A passed method name providing context on where ``__finalize__``
+            was called.
 
+            .. warning:
+
+               The value passed as `method` are not currently considered
+               stable across pandas releases.
         """
         if isinstance(other, NDFrame):
             for name in other.attrs:

From fc74c767df38567507a9c1debda6ecaceaf3efb1 Mon Sep 17 00:00:00 2001
From: Tom Augspurger <tom.w.augspurger@gmail.com>
Date: Mon, 6 Apr 2020 14:55:26 -0500
Subject: [PATCH 3/3] remove underscored

---
 pandas/core/frame.py         |  2 +-
 pandas/core/generic.py       | 36 +++++++++++++-----------------------
 pandas/core/indexes/multi.py |  2 +-
 pandas/core/ops/__init__.py  |  2 +-
 pandas/core/series.py        |  6 ++----
 5 files changed, 18 insertions(+), 30 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 41646e4fb7407..aedbba755227d 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2656,7 +2656,7 @@ def _getitem_multilevel(self, key):
                 result = self._constructor(
                     new_values, index=self.index, columns=result_columns
                 )
-                result = result.__finalize__(self, method="_getitem_multilevel")
+                result = result.__finalize__(self)
 
             # If there is only one column being returned, and its name is
             # either an empty string, or a tuple with an empty string as its
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 0b0525da14557..16725e72d5df2 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -144,9 +144,7 @@ def _single_replace(self, to_replace, method, inplace, limit):
     if values.dtype == orig_dtype and inplace:
         return
 
-    result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(
-        self, method="_single_replace"
-    )
+    result = pd.Series(values, index=self.index, dtype=self.dtype).__finalize__(self)
 
     if inplace:
         self._update_inplace(result)
@@ -3574,7 +3572,7 @@ def _slice(self: FrameOrSeries, slobj: slice, axis=0) -> FrameOrSeries:
         assert isinstance(slobj, slice), type(slobj)
         axis = self._get_block_manager_axis(axis)
         result = self._constructor(self._mgr.get_slice(slobj, axis=axis))
-        result = result.__finalize__(self, method="_slice")
+        result = result.__finalize__(self)
 
         # this could be a view
         # but only in a single-dtyped view sliceable case
@@ -4509,9 +4507,7 @@ def _reindex_with_indexers(
         if copy and new_data is self._mgr:
             new_data = new_data.copy()
 
-        return self._constructor(new_data).__finalize__(
-            self, method="_reindex_with_indexers"
-        )
+        return self._constructor(new_data).__finalize__(self)
 
     def filter(
         self: FrameOrSeries,
@@ -5277,9 +5273,7 @@ def _consolidate(self, inplace: bool_t = False):
         else:
             f = lambda: self._mgr.consolidate()
             cons_data = self._protect_consolidate(f)
-            return self._constructor(cons_data).__finalize__(
-                self, method="_consolidate"
-            )
+            return self._constructor(cons_data).__finalize__(self)
 
     @property
     def _is_mixed_type(self) -> bool_t:
@@ -5308,14 +5302,10 @@ def _check_inplace_setting(self, value) -> bool_t:
         return True
 
     def _get_numeric_data(self):
-        return self._constructor(self._mgr.get_numeric_data()).__finalize__(
-            self, method="_get_numeric_data"
-        )
+        return self._constructor(self._mgr.get_numeric_data()).__finalize__(self,)
 
     def _get_bool_data(self):
-        return self._constructor(self._mgr.get_bool_data()).__finalize__(
-            self, method="_get_bool_data"
-        )
+        return self._constructor(self._mgr.get_bool_data()).__finalize__(self,)
 
     # ----------------------------------------------------------------------
     # Internal Interface Methods
@@ -5442,7 +5432,7 @@ def _to_dict_of_blocks(self, copy: bool_t = True):
         Internal ONLY
         """
         return {
-            k: self._constructor(v).__finalize__(self, method="_to_dict_of_blocks")
+            k: self._constructor(v).__finalize__(self)
             for k, v, in self._mgr.to_dict(copy=copy).items()
         }
 
@@ -5755,7 +5745,7 @@ def _convert(
                 coerce=coerce,
                 copy=copy,
             )
-        ).__finalize__(self, method="_convert")
+        ).__finalize__(self)
 
     def infer_objects(self: FrameOrSeries) -> FrameOrSeries:
         """
@@ -8455,8 +8445,8 @@ def _align_frame(
                     right.index = join_index
 
         return (
-            left.__finalize__(self, method="_align_frame"),
-            right.__finalize__(other, method="_align_frame"),
+            left.__finalize__(self),
+            right.__finalize__(other),
         )
 
     def _align_series(
@@ -8542,8 +8532,8 @@ def _align_series(
                         right.index = join_index
 
         return (
-            left.__finalize__(self, method="_align_series"),
-            right.__finalize__(other, method="_align_series"),
+            left.__finalize__(self),
+            right.__finalize__(other),
         )
 
     def _where(
@@ -8685,7 +8675,7 @@ def _where(
                 axis=block_axis,
             )
             result = self._constructor(new_data)
-            return result.__finalize__(self, method="_where")
+            return result.__finalize__(self)
 
     _shared_docs[
         "where"
diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index 5290a8885a21e..4e2d07ddf9225 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -2365,7 +2365,7 @@ def _get_values_for_loc(self, series: "Series", loc, key):
         new_index = self[loc]
         new_index = maybe_droplevels(new_index, key)
         new_ser = series._constructor(new_values, index=new_index, name=series.name)
-        return new_ser.__finalize__(series, method="_get_values_for_loc")
+        return new_ser.__finalize__(series)
 
     def _convert_listlike_indexer(self, keyarr):
         """
diff --git a/pandas/core/ops/__init__.py b/pandas/core/ops/__init__.py
index 9d3d595aa7eab..d6ba9d763366b 100644
--- a/pandas/core/ops/__init__.py
+++ b/pandas/core/ops/__init__.py
@@ -413,7 +413,7 @@ def _construct_result(
     # We do not pass dtype to ensure that the Series constructor
     #  does inference in the case where `result` has object-dtype.
     out = left._constructor(result, index=index)
-    out = out.__finalize__(left, method="_construct_result")
+    out = out.__finalize__(left)
 
     # Set the result's name after __finalize__ is called because __finalize__
     #  would set it back to self.name
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 4e3f370047f20..ccb1ec25b5ba4 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -962,14 +962,12 @@ def _get_values_tuple(self, key):
         # If key is contained, would have returned by now
         indexer, new_index = self.index.get_loc_level(key)
         return self._constructor(self._values[indexer], index=new_index).__finalize__(
-            self, method="_get_values_tuple",
+            self,
         )
 
     def _get_values(self, indexer):
         try:
-            return self._constructor(self._mgr.get_slice(indexer)).__finalize__(
-                self, method="_get_values"
-            )
+            return self._constructor(self._mgr.get_slice(indexer)).__finalize__(self,)
         except ValueError:
             # mpl compat if we look up e.g. ser[:, np.newaxis];
             #  see tests.series.timeseries.test_mpl_compat_hack