TYP: @Final for Block methods (#39865)

Author: jbrockmendel

pandas/core/internals/blocks.py

@@ -32,6 +32,7 @@
     Dtype,
     DtypeObj,
     Shape,
+    final,
 )
 from pandas.util._validators import validate_bool_kwarg
 
@@ -231,6 +232,7 @@ def _holder(self):
         """
         return None
 
+    @final
     @property
     def _consolidate_key(self):
         return self._can_consolidate, self.dtype.name
@@ -242,6 +244,7 @@ def is_view(self) -> bool:
         values = cast(np.ndarray, values)
         return values.base is not None
 
+    @final
     @property
     def is_categorical(self) -> bool:
         return self._holder is Categorical
@@ -278,6 +281,7 @@ def get_values(self, dtype: Optional[DtypeObj] = None) -> np.ndarray:
             return self.values.astype(object)
         return self.values
 
+    @final
     def get_block_values_for_json(self) -> np.ndarray:
         """
         This is used in the JSON C code.
@@ -300,6 +304,7 @@ def mgr_locs(self, new_mgr_locs):
 
         self._mgr_locs = new_mgr_locs
 
+    @final
     def make_block(self, values, placement=None) -> Block:
         """
         Create a new block, with type inference propagate any values that are
@@ -312,14 +317,14 @@ def make_block(self, values, placement=None) -> Block:
 
         return make_block(values, placement=placement, ndim=self.ndim)
 
-    def make_block_same_class(self, values, placement=None, ndim=None) -> Block:
+    @final
+    def make_block_same_class(self, values, placement=None) -> Block:
         """ Wrap given values in a block of same type as self. """
         if placement is None:
             placement = self.mgr_locs
-        if ndim is None:
-            ndim = self.ndim
-        return type(self)(values, placement=placement, ndim=ndim)
+        return type(self)(values, placement=placement, ndim=self.ndim)
 
+    @final
     def __repr__(self) -> str:
         # don't want to print out all of the items here
         name = type(self).__name__
@@ -332,12 +337,15 @@ def __repr__(self) -> str:
 
         return result
 
+    @final
     def __len__(self) -> int:
         return len(self.values)
 
+    @final
     def __getstate__(self):
         return self.mgr_locs.indexer, self.values
 
+    @final
     def __setstate__(self, state):
         self.mgr_locs = libinternals.BlockPlacement(state[0])
         self.values = state[1]
@@ -348,6 +356,7 @@ def _slice(self, slicer):
 
         return self.values[slicer]
 
+    @final
     def getitem_block(self, slicer, new_mgr_locs=None) -> Block:
         """
         Perform __getitem__-like, return result as block.
@@ -371,6 +380,7 @@ def getitem_block(self, slicer, new_mgr_locs=None) -> Block:
     def shape(self) -> Shape:
         return self.values.shape
 
+    @final
     @property
     def dtype(self) -> DtypeObj:
         return self.values.dtype
@@ -389,13 +399,15 @@ def set_inplace(self, locs, values):
         """
         self.values[locs] = values
 
+    @final
     def delete(self, loc) -> None:
         """
         Delete given loc(-s) from block in-place.
         """
         self.values = np.delete(self.values, loc, 0)
         self.mgr_locs = self.mgr_locs.delete(loc)
 
+    @final
     def apply(self, func, **kwargs) -> List[Block]:
         """
         apply the function to my values; return a block if we are not
@@ -427,6 +439,7 @@ def reduce(self, func, ignore_failures: bool = False) -> List[Block]:
         nb = self.make_block(res_values)
         return [nb]
 
+    @final
     def _split_op_result(self, result) -> List[Block]:
         # See also: split_and_operate
         if is_extension_array_dtype(result) and result.ndim > 1:
@@ -487,6 +500,7 @@ def f(mask, val, idx):
 
         return self.split_and_operate(None, f, inplace)
 
+    @final
     def _split(self) -> List[Block]:
         """
         Split a block into a list of single-column blocks.
@@ -501,6 +515,7 @@ def _split(self) -> List[Block]:
             new_blocks.append(nb)
         return new_blocks
 
+    @final
     def split_and_operate(
         self, mask, f, inplace: bool, ignore_failures: bool = False
     ) -> List[Block]:
@@ -617,6 +632,7 @@ def f(mask, val, idx):
 
         return self.split_and_operate(None, f, False)
 
+    @final
     def astype(self, dtype, copy: bool = False, errors: str = "raise"):
         """
         Coerce to the new dtype.
@@ -720,6 +736,7 @@ def _can_hold_element(self, element: Any) -> bool:
         """ require the same dtype as ourselves """
         raise NotImplementedError("Implemented on subclasses")
 
+    @final
     def should_store(self, value: ArrayLike) -> bool:
         """
         Should we set self.values[indexer] = value inplace or do we need to cast?
@@ -753,12 +770,13 @@ def to_native_types(self, na_rep="nan", quoting=None, **kwargs):
         return self.make_block(values)
 
     # block actions #
+    @final
     def copy(self, deep: bool = True):
         """ copy constructor """
         values = self.values
         if deep:
             values = values.copy()
-        return self.make_block_same_class(values, ndim=self.ndim)
+        return self.make_block_same_class(values)
 
     # ---------------------------------------------------------------------
     # Replace
@@ -807,6 +825,7 @@ def replace(
         blocks = blk.convert(numeric=False, copy=not inplace)
         return blocks
 
+    @final
     def _replace_regex(
         self,
         to_replace,
@@ -852,6 +871,7 @@ def _replace_regex(
             nbs = [block]
         return nbs
 
+    @final
     def _replace_list(
         self,
         src_list: List[Any],
@@ -913,6 +933,7 @@ def _replace_list(
             rb = new_rb
         return rb
 
+    @final
     def _replace_coerce(
         self,
         to_replace,
@@ -1147,6 +1168,7 @@ def f(mask, val, idx):
             new_blocks = self.split_and_operate(mask, f, True)
             return new_blocks
 
+    @final
     def coerce_to_target_dtype(self, other) -> Block:
         """
         coerce the current block to a dtype compat for other
@@ -1162,6 +1184,7 @@ def coerce_to_target_dtype(self, other) -> Block:
 
         return self.astype(new_dtype, copy=False)
 
+    @final
     def interpolate(
         self,
         method: str = "pad",
@@ -1220,6 +1243,7 @@ def interpolate(
             **kwargs,
         )
 
+    @final
     def _interpolate_with_fill(
         self,
         method: str = "pad",
@@ -1244,9 +1268,10 @@ def _interpolate_with_fill(
             limit_area=limit_area,
         )
 
-        blocks = [self.make_block_same_class(values, ndim=self.ndim)]
+        blocks = [self.make_block_same_class(values)]
         return self._maybe_downcast(blocks, downcast)
 
+    @final
     def _interpolate(
         self,
         method: str,
@@ -1459,7 +1484,7 @@ def _unstack(self, unstacker, fill_value, new_placement):
         new_values = new_values.T[mask]
         new_placement = new_placement[mask]
 
-        blocks = [make_block(new_values, placement=new_placement)]
+        blocks = [make_block(new_values, placement=new_placement, ndim=2)]
         return blocks, mask
 
     def quantile(
@@ -1761,21 +1786,15 @@ def fillna(
     ) -> List[Block]:
         values = self.values if inplace else self.values.copy()
         values = values.fillna(value=value, limit=limit)
-        return [
-            self.make_block_same_class(
-                values=values, placement=self.mgr_locs, ndim=self.ndim
-            )
-        ]
+        return [self.make_block_same_class(values=values)]
 
     def interpolate(
         self, method="pad", axis=0, inplace=False, limit=None, fill_value=None, **kwargs
     ):
 
         values = self.values if inplace else self.values.copy()
-        return self.make_block_same_class(
-            values=values.fillna(value=fill_value, method=method, limit=limit),
-            placement=self.mgr_locs,
-        )
+        new_values = values.fillna(value=fill_value, method=method, limit=limit)
+        return self.make_block_same_class(new_values)
 
     def diff(self, n: int, axis: int = 1) -> List[Block]:
         if axis == 0 and n != 0:
@@ -1797,13 +1816,8 @@ def shift(self, periods: int, axis: int = 0, fill_value: Any = None) -> List[Blo
         Dispatches to underlying ExtensionArray and re-boxes in an
         ExtensionBlock.
         """
-        return [
-            self.make_block_same_class(
-                self.values.shift(periods=periods, fill_value=fill_value),
-                placement=self.mgr_locs,
-                ndim=self.ndim,
-            )
-        ]
+        new_values = self.values.shift(periods=periods, fill_value=fill_value)
+        return [self.make_block_same_class(new_values)]
 
     def where(self, other, cond, errors="raise", axis: int = 0) -> List[Block]:
 
@@ -1850,7 +1864,7 @@ def where(self, other, cond, errors="raise", axis: int = 0) -> List[Block]:
                 np.where(cond, self.values, other), dtype=dtype
             )
 
-        return [self.make_block_same_class(result, placement=self.mgr_locs)]
+        return [self.make_block_same_class(result)]
 
     def _unstack(self, unstacker, fill_value, new_placement):
         # ExtensionArray-safe unstack.

pandas/core/internals/managers.py

@@ -215,7 +215,7 @@ def make_empty(self: T, axes=None) -> T:
             assert isinstance(self, SingleBlockManager)  # for mypy
             blk = self.blocks[0]
             arr = blk.values[:0]
-            nb = blk.make_block_same_class(arr, placement=slice(0, 0), ndim=1)
+            nb = blk.make_block_same_class(arr, placement=slice(0, 0))
             blocks = [nb]
         else:
             blocks = []
@@ -967,12 +967,8 @@ def iget(self, i: int) -> SingleBlockManager:
         values = block.iget(self.blklocs[i])
 
         # shortcut for select a single-dim from a 2-dim BM
-        return SingleBlockManager(
-            block.make_block_same_class(
-                values, placement=slice(0, len(values)), ndim=1
-            ),
-            self.axes[1],
-        )
+        nb = type(block)(values, placement=slice(0, len(values)), ndim=1)
+        return SingleBlockManager(nb, self.axes[1])
 
     def iget_values(self, i: int) -> ArrayLike:
         """