TYP: plotting (#55829)

* TYP: plotting

* mypy fixup

pandas/plotting/_matplotlib/core.py

@@ -12,6 +12,7 @@
 from typing import (
     TYPE_CHECKING,
     Literal,
+    final,
 )
 import warnings
 
@@ -274,6 +275,7 @@ def __init__(
 
         self._validate_color_args()
 
+    @final
     def _validate_subplots_kwarg(
         self, subplots: bool | Sequence[Sequence[str]]
     ) -> bool | list[tuple[int, ...]]:
@@ -420,6 +422,7 @@ def _validate_color_args(self):
                         "other or pass 'style' without a color symbol"
                     )
 
+    @final
     def _iter_data(self, data=None, keep_index: bool = False, fillna=None):
         if data is None:
             data = self.data
@@ -445,9 +448,11 @@ def nseries(self) -> int:
         else:
             return self.data.shape[1]
 
+    @final
     def draw(self) -> None:
         self.plt.draw_if_interactive()
 
+    @final
     def generate(self) -> None:
         self._args_adjust()
         self._compute_plot_data()
@@ -465,11 +470,13 @@ def generate(self) -> None:
     def _args_adjust(self) -> None:
         pass
 
+    @final
     def _has_plotted_object(self, ax: Axes) -> bool:
         """check whether ax has data"""
         return len(ax.lines) != 0 or len(ax.artists) != 0 or len(ax.containers) != 0
 
-    def _maybe_right_yaxis(self, ax: Axes, axes_num):
+    @final
+    def _maybe_right_yaxis(self, ax: Axes, axes_num: int):
         if not self.on_right(axes_num):
             # secondary axes may be passed via ax kw
             return self._get_ax_layer(ax)
@@ -497,6 +504,7 @@ def _maybe_right_yaxis(self, ax: Axes, axes_num):
                 new_ax.set_yscale("symlog")
             return new_ax
 
+    @final
     def _setup_subplots(self) -> Figure:
         if self.subplots:
             naxes = (
@@ -567,6 +575,7 @@ def result(self):
             else:
                 return self.axes[0]
 
+    @final
     def _convert_to_ndarray(self, data):
         # GH31357: categorical columns are processed separately
         if isinstance(data.dtype, CategoricalDtype):
@@ -585,6 +594,7 @@ def _convert_to_ndarray(self, data):
 
         return data
 
+    @final
     def _compute_plot_data(self):
         data = self.data
 
@@ -642,6 +652,7 @@ def _compute_plot_data(self):
     def _make_plot(self, fig: Figure):
         raise AbstractMethodError(self)
 
+    @final
     def _add_table(self) -> None:
         if self.table is False:
             return
@@ -652,6 +663,7 @@ def _add_table(self) -> None:
         ax = self._get_ax(0)
         tools.table(ax, data)
 
+    @final
     def _post_plot_logic_common(self, ax, data):
         """Common post process for each axes"""
         if self.orientation == "vertical" or self.orientation is None:
@@ -674,6 +686,7 @@ def _post_plot_logic_common(self, ax, data):
     def _post_plot_logic(self, ax, data) -> None:
         """Post process for each axes. Overridden in child classes"""
 
+    @final
     def _adorn_subplots(self, fig: Figure):
         """Common post process unrelated to data"""
         if len(self.axes) > 0:
@@ -735,6 +748,7 @@ def _adorn_subplots(self, fig: Figure):
                     raise ValueError(msg)
                 self.axes[0].set_title(self.title)
 
+    @final
     def _apply_axis_properties(
         self, axis: Axis, rot=None, fontsize: int | None = None
     ) -> None:
@@ -764,6 +778,7 @@ def legend_title(self) -> str | None:
             stringified = map(pprint_thing, self.data.columns.names)
             return ",".join(stringified)
 
+    @final
     def _mark_right_label(self, label: str, index: int) -> str:
         """
         Append ``(right)`` to the label of a line if it's plotted on the right axis.
@@ -774,6 +789,7 @@ def _mark_right_label(self, label: str, index: int) -> str:
             label += " (right)"
         return label
 
+    @final
     def _append_legend_handles_labels(self, handle: Artist, label: str) -> None:
         """
         Append current handle and label to ``legend_handles`` and ``legend_labels``.
@@ -819,6 +835,7 @@ def _make_legend(self) -> None:
                 if ax.get_visible():
                     ax.legend(loc="best")
 
+    @final
     def _get_ax_legend(self, ax: Axes):
         """
         Take in axes and return ax and legend under different scenarios
@@ -834,6 +851,7 @@ def _get_ax_legend(self, ax: Axes):
             ax = other_ax
         return ax, leg
 
+    @final
     @cache_readonly
     def plt(self):
         import matplotlib.pyplot as plt
@@ -842,6 +860,7 @@ def plt(self):
 
     _need_to_set_index = False
 
+    @final
     def _get_xticks(self, convert_period: bool = False):
         index = self.data.index
         is_datetype = index.inferred_type in ("datetime", "date", "datetime64", "time")
@@ -896,6 +915,7 @@ def _get_custom_index_name(self):
         """Specify whether xlabel/ylabel should be used to override index name"""
         return self.xlabel
 
+    @final
     def _get_index_name(self) -> str | None:
         if isinstance(self.data.index, ABCMultiIndex):
             name = self.data.index.names
@@ -915,6 +935,7 @@ def _get_index_name(self) -> str | None:
 
         return name
 
+    @final
     @classmethod
     def _get_ax_layer(cls, ax, primary: bool = True):
         """get left (primary) or right (secondary) axes"""
@@ -923,6 +944,7 @@ def _get_ax_layer(cls, ax, primary: bool = True):
         else:
             return getattr(ax, "right_ax", ax)
 
+    @final
     def _col_idx_to_axis_idx(self, col_idx: int) -> int:
         """Return the index of the axis where the column at col_idx should be plotted"""
         if isinstance(self.subplots, list):
@@ -936,6 +958,7 @@ def _col_idx_to_axis_idx(self, col_idx: int) -> int:
             # subplots is True: one ax per column
             return col_idx
 
+    @final
     def _get_ax(self, i: int):
         # get the twinx ax if appropriate
         if self.subplots:
@@ -950,6 +973,7 @@ def _get_ax(self, i: int):
         ax.get_yaxis().set_visible(True)
         return ax
 
+    @final
     @classmethod
     def get_default_ax(cls, ax) -> None:
         import matplotlib.pyplot as plt
@@ -959,13 +983,15 @@ def get_default_ax(cls, ax) -> None:
                 ax = plt.gca()
             ax = cls._get_ax_layer(ax)
 
-    def on_right(self, i):
+    @final
+    def on_right(self, i: int):
         if isinstance(self.secondary_y, bool):
             return self.secondary_y
 
         if isinstance(self.secondary_y, (tuple, list, np.ndarray, ABCIndex)):
             return self.data.columns[i] in self.secondary_y
 
+    @final
     def _apply_style_colors(self, colors, kwds, col_num, label: str):
         """
         Manage style and color based on column number and its label.
@@ -1006,6 +1032,7 @@ def _get_colors(
             color=self.kwds.get(color_kwds),
         )
 
+    @final
     def _parse_errorbars(self, label, err):
         """
         Look for error keyword arguments and return the actual errorbar data
@@ -1095,6 +1122,7 @@ def match_labels(data, e):
 
         return err
 
+    @final
     def _get_errorbars(
         self, label=None, index=None, xerr: bool = True, yerr: bool = True
     ):
@@ -1116,6 +1144,7 @@ def _get_errorbars(
                     errors[kw] = err
         return errors
 
+    @final
     def _get_subplots(self, fig: Figure):
         from matplotlib.axes import Subplot
 
@@ -1125,6 +1154,7 @@ def _get_subplots(self, fig: Figure):
             if (isinstance(ax, Subplot) and ax.get_subplotspec() is not None)
         ]
 
+    @final
     def _get_axes_layout(self, fig: Figure) -> tuple[int, int]:
         axes = self._get_subplots(fig)
         x_set = set()
@@ -1163,17 +1193,20 @@ def __init__(self, data, x, y, **kwargs) -> None:
         self.x = x
         self.y = y
 
+    @final
     @property
     def nseries(self) -> int:
         return 1
 
+    @final
     def _post_plot_logic(self, ax: Axes, data) -> None:
         x, y = self.x, self.y
         xlabel = self.xlabel if self.xlabel is not None else pprint_thing(x)
         ylabel = self.ylabel if self.ylabel is not None else pprint_thing(y)
         ax.set_xlabel(xlabel)
         ax.set_ylabel(ylabel)
 
+    @final
     def _plot_colorbar(self, ax: Axes, *, fig: Figure, **kwds):
         # Addresses issues #10611 and #10678:
         # When plotting scatterplots and hexbinplots in IPython
@@ -1353,10 +1386,12 @@ def __init__(self, data, **kwargs) -> None:
         if "x_compat" in self.kwds:
             self.x_compat = bool(self.kwds.pop("x_compat"))
 
+    @final
     def _is_ts_plot(self) -> bool:
         # this is slightly deceptive
         return not self.x_compat and self.use_index and self._use_dynamic_x()
 
+    @final
     def _use_dynamic_x(self):
         return use_dynamic_x(self._get_ax(0), self.data)
 
@@ -1424,6 +1459,7 @@ def _plot(  # type: ignore[override]
         cls._update_stacker(ax, stacking_id, y)
         return lines
 
+    @final
     def _ts_plot(self, ax: Axes, x, data, style=None, **kwds):
         # accept x to be consistent with normal plot func,
         # x is not passed to tsplot as it uses data.index as x coordinate
@@ -1444,12 +1480,14 @@ def _ts_plot(self, ax: Axes, x, data, style=None, **kwds):
         format_dateaxis(ax, ax.freq, data.index)
         return lines
 
+    @final
     def _get_stacking_id(self):
         if self.stacked:
             return id(self.data)
         else:
             return None
 
+    @final
     @classmethod
     def _initialize_stacker(cls, ax: Axes, stacking_id, n: int) -> None:
         if stacking_id is None:
@@ -1461,6 +1499,7 @@ def _initialize_stacker(cls, ax: Axes, stacking_id, n: int) -> None:
         ax._stacker_pos_prior[stacking_id] = np.zeros(n)
         ax._stacker_neg_prior[stacking_id] = np.zeros(n)
 
+    @final
     @classmethod
     def _get_stacked_values(cls, ax: Axes, stacking_id, values, label):
         if stacking_id is None:
@@ -1480,6 +1519,7 @@ def _get_stacked_values(cls, ax: Axes, stacking_id, values, label):
             f"Column '{label}' contains both positive and negative values"
         )
 
+    @final
     @classmethod
     def _update_stacker(cls, ax: Axes, stacking_id, values) -> None:
         if stacking_id is None: