From 8a1f201c898aa7a509ba1d56670976ba51b0155b Mon Sep 17 00:00:00 2001
From: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Date: Thu, 9 Apr 2026 22:35:13 +0200
Subject: [PATCH 1/2] TYP: Add type information to the data parameter of plot
 functions

Closes #31480.

We type all as `Mapping[str, Any]`. Some uses have actually a broad
range of supported types because they map quite a number of parameters.

Even for the ones which we know all parameters supported by `data` are
ArrayLike, typing as `Mapping[str, ArrayLike]` may be too risky, as the
user may have more keys in the data structure, which we don't use, but
their values would be type checked and could be anything.
---
 lib/matplotlib/axes/_axes.pyi |  81 ++++++++++++-------------
 lib/matplotlib/pyplot.py      | 107 +++++++++++++++++-----------------
 lib/matplotlib/typing.py      |   5 +-
 3 files changed, 99 insertions(+), 94 deletions(-)

diff --git a/lib/matplotlib/axes/_axes.pyi b/lib/matplotlib/axes/_axes.pyi
index 09587ab753a3..3c222bd6bc1d 100644
--- a/lib/matplotlib/axes/_axes.pyi
+++ b/lib/matplotlib/axes/_axes.pyi
@@ -37,7 +37,8 @@ from collections.abc import Callable, Iterable, Sequence
 from typing import Any, Literal, overload
 import numpy as np
 from numpy.typing import ArrayLike
-from matplotlib.typing import ColorType, MarkerType, LegendLocType, LineStyleType
+from matplotlib.typing import (
+    ColorType, DataParamType, MarkerType, LegendLocType, LineStyleType)
 import pandas as pd
 
 
@@ -172,7 +173,7 @@ class Axes(_AxesBase):
         linestyles: LineStyleType = ...,
         *,
         label: str = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> LineCollection: ...
     def vlines(
@@ -184,7 +185,7 @@ class Axes(_AxesBase):
         linestyles: LineStyleType = ...,
         *,
         label: str = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> LineCollection: ...
     def eventplot(
@@ -198,7 +199,7 @@ class Axes(_AxesBase):
         colors: ColorType | Sequence[ColorType] | None = ...,
         alpha: float | Sequence[float] | None = ...,
         linestyles: LineStyleType | Sequence[LineStyleType] = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> EventCollection: ...
     def plot(
@@ -206,14 +207,14 @@ class Axes(_AxesBase):
         *args: float | ArrayLike | str,
         scalex: bool = ...,
         scaley: bool = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> list[Line2D]: ...
     def loglog(self, *args, **kwargs) -> list[Line2D]: ...
     def semilogx(self, *args, **kwargs) -> list[Line2D]: ...
     def semilogy(self, *args, **kwargs) -> list[Line2D]: ...
     def acorr(
-        self, x: ArrayLike, *, data=..., **kwargs
+        self, x: ArrayLike, *, data: DataParamType = ..., **kwargs
     ) -> tuple[np.ndarray, np.ndarray, LineCollection | Line2D, Line2D | None]: ...
     def xcorr(
         self,
@@ -224,7 +225,7 @@ class Axes(_AxesBase):
         detrend: Callable[[ArrayLike], ArrayLike] = ...,
         usevlines: bool = ...,
         maxlags: int = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, LineCollection | Line2D, Line2D | None]: ...
     def step(
@@ -233,7 +234,7 @@ class Axes(_AxesBase):
         y: ArrayLike,
         *args,
         where: Literal["pre", "post", "mid"] = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> list[Line2D]: ...
     def bar(
@@ -244,7 +245,7 @@ class Axes(_AxesBase):
         bottom: float | ArrayLike | None = ...,
         *,
         align: Literal["center", "edge"] = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> BarContainer: ...
     def barh(
@@ -255,7 +256,7 @@ class Axes(_AxesBase):
         left: float | ArrayLike | None = ...,
         *,
         align: Literal["center", "edge"] = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> BarContainer: ...
     def bar_label(
@@ -274,7 +275,7 @@ class Axes(_AxesBase):
         yrange: tuple[float, float],
         align: Literal["bottom", "center", "top"] = ...,
         *,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> PolyCollection: ...
     def grouped_bar(
@@ -299,7 +300,7 @@ class Axes(_AxesBase):
         bottom: float = ...,
         label: str | None = ...,
         orientation: Literal["vertical", "horizontal"] = ...,
-        data=...,
+        data: DataParamType = ...,
     ) -> StemContainer: ...
 
     # TODO: data kwarg preprocessor?
@@ -324,7 +325,7 @@ class Axes(_AxesBase):
         rotatelabels: bool = ...,
         normalize: bool = ...,
         hatch: str | Sequence[str] | None = ...,
-        data=...,
+        data: DataParamType = ...,
     ) -> PieContainer: ...
     def pie_label(
         self,
@@ -356,7 +357,7 @@ class Axes(_AxesBase):
         xuplims: bool | ArrayLike = ...,
         errorevery: int | tuple[int, int] = ...,
         capthick: float | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> ErrorbarContainer: ...
     def boxplot(
@@ -391,7 +392,7 @@ class Axes(_AxesBase):
         zorder: float | None = ...,
         capwidths: float | ArrayLike | None = ...,
         label: Sequence[str] | None = ...,
-        data=...,
+        data: DataParamType = ...,
     ) -> dict[str, Any]: ...
     def bxp(
         self,
@@ -436,7 +437,7 @@ class Axes(_AxesBase):
         edgecolors: Literal["face", "none"] | ColorType | Sequence[ColorType] | None = ...,
         colorizer: Colorizer | None = ...,
         plotnonfinite: bool = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> PathCollection: ...
     def hexbin(
@@ -461,7 +462,7 @@ class Axes(_AxesBase):
         mincnt: int | None = ...,
         marginals: bool = ...,
         colorizer: Colorizer | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> PolyCollection: ...
     def arrow(
@@ -470,9 +471,9 @@ class Axes(_AxesBase):
     def quiverkey(
         self, Q: Quiver, X: float, Y: float, U: float, label: str, **kwargs
     ) -> QuiverKey: ...
-    def quiver(self, *args, data=..., **kwargs) -> Quiver: ...
-    def barbs(self, *args, data=..., **kwargs) -> Barbs: ...
-    def fill(self, *args, data=..., **kwargs) -> list[Polygon]: ...
+    def quiver(self, *args, data: DataParamType = ..., **kwargs) -> Quiver: ...
+    def barbs(self, *args, data: DataParamType = ..., **kwargs) -> Barbs: ...
+    def fill(self, *args, data: DataParamType = ..., **kwargs) -> list[Polygon]: ...
     def fill_between(
         self,
         x: ArrayLike,
@@ -482,7 +483,7 @@ class Axes(_AxesBase):
         interpolate: bool = ...,
         step: Literal["pre", "post", "mid"] | None = ...,
         *,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> FillBetweenPolyCollection: ...
     def fill_betweenx(
@@ -494,7 +495,7 @@ class Axes(_AxesBase):
         step: Literal["pre", "post", "mid"] | None = ...,
         interpolate: bool = ...,
         *,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> FillBetweenPolyCollection: ...
     def imshow(
@@ -516,7 +517,7 @@ class Axes(_AxesBase):
         filterrad: float = ...,
         resample: bool | None = ...,
         url: str | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> AxesImage: ...
     def pcolor(
@@ -529,7 +530,7 @@ class Axes(_AxesBase):
         vmin: float | None = ...,
         vmax: float | None = ...,
         colorizer: Colorizer | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> Collection: ...
     def pcolormesh(
@@ -543,7 +544,7 @@ class Axes(_AxesBase):
         colorizer: Colorizer | None = ...,
         shading: Literal["flat", "nearest", "gouraud", "auto"] | None = ...,
         antialiased: bool = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> QuadMesh: ...
     def pcolorfast(
@@ -555,11 +556,11 @@ class Axes(_AxesBase):
         vmin: float | None = ...,
         vmax: float | None = ...,
         colorizer: Colorizer | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> AxesImage | PcolorImage | QuadMesh: ...
-    def contour(self, *args, data=..., **kwargs) -> QuadContourSet: ...
-    def contourf(self, *args, data=..., **kwargs) -> QuadContourSet: ...
+    def contour(self, *args, data: DataParamType = ..., **kwargs) -> QuadContourSet: ...
+    def contourf(self, *args, data: DataParamType = ..., **kwargs) -> QuadContourSet: ...
     def clabel(
         self, CS: ContourSet, levels: ArrayLike | None = ..., **kwargs
     ) -> list[Text]: ...
@@ -581,7 +582,7 @@ class Axes(_AxesBase):
         color: ColorType | Sequence[ColorType] | None = ...,
         label: str | Sequence[str] | None = ...,
         stacked: bool = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[
         np.ndarray | list[np.ndarray],
@@ -596,7 +597,7 @@ class Axes(_AxesBase):
         orientation: Literal["vertical", "horizontal"] = ...,
         baseline: float | ArrayLike | None = ...,
         fill: bool = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> StepPatch: ...
     def hist2d(
@@ -614,7 +615,7 @@ class Axes(_AxesBase):
         weights: ArrayLike | None = ...,
         cmin: float | None = ...,
         cmax: float | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, np.ndarray, QuadMesh]: ...
     def ecdf(
@@ -625,7 +626,7 @@ class Axes(_AxesBase):
         complementary: bool=...,
         orientation: Literal["vertical", "horizontal"]=...,
         compress: bool=...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> Line2D: ...
     def psd(
@@ -644,7 +645,7 @@ class Axes(_AxesBase):
         sides: Literal["default", "onesided", "twosided"] | None = ...,
         scale_by_freq: bool | None = ...,
         return_line: bool | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray] | tuple[np.ndarray, np.ndarray, Line2D]: ...
     def csd(
@@ -664,7 +665,7 @@ class Axes(_AxesBase):
         sides: Literal["default", "onesided", "twosided"] | None = ...,
         scale_by_freq: bool | None = ...,
         return_line: bool | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray] | tuple[np.ndarray, np.ndarray, Line2D]: ...
     def magnitude_spectrum(
@@ -677,7 +678,7 @@ class Axes(_AxesBase):
         pad_to: int | None = ...,
         sides: Literal["default", "onesided", "twosided"] | None = ...,
         scale: Literal["default", "linear", "dB"] | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, Line2D]: ...
     def angle_spectrum(
@@ -689,7 +690,7 @@ class Axes(_AxesBase):
         window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = ...,
         pad_to: int | None = ...,
         sides: Literal["default", "onesided", "twosided"] | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, Line2D]: ...
     def phase_spectrum(
@@ -701,7 +702,7 @@ class Axes(_AxesBase):
         window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = ...,
         pad_to: int | None = ...,
         sides: Literal["default", "onesided", "twosided"] | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, Line2D]: ...
     def cohere(
@@ -719,7 +720,7 @@ class Axes(_AxesBase):
         pad_to: int | None = ...,
         sides: Literal["default", "onesided", "twosided"] = ...,
         scale_by_freq: bool | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray]: ...
     def specgram(
@@ -743,7 +744,7 @@ class Axes(_AxesBase):
         scale: Literal["default", "linear", "dB"] | None = ...,
         vmin: float | None = ...,
         vmax: float | None = ...,
-        data=...,
+        data: DataParamType = ...,
         **kwargs
     ) -> tuple[np.ndarray, np.ndarray, np.ndarray, AxesImage]: ...
     def spy(
@@ -778,7 +779,7 @@ class Axes(_AxesBase):
         side: Literal["both", "low", "high"] = ...,
         facecolor: Sequence[ColorType] | ColorType | None = ...,
         linecolor: Sequence[ColorType] | ColorType | None = ...,
-        data=...,
+        data: DataParamType = ...,
     ) -> dict[str, Collection]: ...
     def violin(
         self,
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index ed7821ca1b27..777bc4877aa9 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -140,6 +140,7 @@
         CloseEventType,
         ColorType,
         CoordsType,
+        DataParamType,
         DrawEventType,
         HashableList,
         KeyEventType,
@@ -2999,7 +3000,7 @@ def waitforbuttonpress(timeout: float = -1) -> None | bool:
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.acorr)
 def acorr(
-    x: ArrayLike, *, data=None, **kwargs
+    x: ArrayLike, *, data: DataParamType = None, **kwargs
 ) -> tuple[np.ndarray, np.ndarray, LineCollection | Line2D, Line2D | None]:
     return gca().acorr(x, **({"data": data} if data is not None else {}), **kwargs)
 
@@ -3014,7 +3015,7 @@ def angle_spectrum(
     pad_to: int | None = None,
     sides: Literal["default", "onesided", "twosided"] | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, Line2D]:
     return gca().angle_spectrum(
@@ -3130,7 +3131,7 @@ def bar(
     bottom: float | ArrayLike | None = None,
     *,
     align: Literal["center", "edge"] = "center",
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> BarContainer:
     return gca().bar(
@@ -3146,7 +3147,7 @@ def bar(
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.barbs)
-def barbs(*args, data=None, **kwargs) -> Barbs:
+def barbs(*args, data: DataParamType = None, **kwargs) -> Barbs:
     return gca().barbs(*args, **({"data": data} if data is not None else {}), **kwargs)
 
 
@@ -3159,7 +3160,7 @@ def barh(
     left: float | ArrayLike | None = None,
     *,
     align: Literal["center", "edge"] = "center",
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> BarContainer:
     return gca().barh(
@@ -3227,7 +3228,7 @@ def boxplot(
     capwidths: float | ArrayLike | None = None,
     label: Sequence[str] | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
 ) -> dict[str, Any]:
     return gca().boxplot(
         x,
@@ -3270,7 +3271,7 @@ def broken_barh(
     yrange: tuple[float, float],
     align: Literal["bottom", "center", "top"] = "bottom",
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> PolyCollection:
     return gca().broken_barh(
@@ -3296,16 +3297,15 @@ def cohere(
     NFFT: int = 256,
     Fs: float = 2,
     Fc: int = 0,
-    detrend: (
-        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike]
-    ) = mlab.detrend_none,
+    detrend: Literal["none", "mean", "linear"]
+    | Callable[[ArrayLike], ArrayLike] = mlab.detrend_none,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike = mlab.window_hanning,
     noverlap: int = 0,
     pad_to: int | None = None,
     sides: Literal["default", "onesided", "twosided"] = "default",
     scale_by_freq: bool | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray]:
     return gca().cohere(
@@ -3327,7 +3327,7 @@ def cohere(
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.contour)
-def contour(*args, data=None, **kwargs) -> QuadContourSet:
+def contour(*args, data: DataParamType = None, **kwargs) -> QuadContourSet:
     __ret = gca().contour(
         *args, **({"data": data} if data is not None else {}), **kwargs
     )
@@ -3338,7 +3338,7 @@ def contour(*args, data=None, **kwargs) -> QuadContourSet:
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.contourf)
-def contourf(*args, data=None, **kwargs) -> QuadContourSet:
+def contourf(*args, data: DataParamType = None, **kwargs) -> QuadContourSet:
     __ret = gca().contourf(
         *args, **({"data": data} if data is not None else {}), **kwargs
     )
@@ -3355,9 +3355,9 @@ def csd(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: (
-        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
-    ) = None,
+    detrend: Literal["none", "mean", "linear"]
+    | Callable[[ArrayLike], ArrayLike]
+    | None = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     pad_to: int | None = None,
@@ -3365,7 +3365,7 @@ def csd(
     scale_by_freq: bool | None = None,
     return_line: bool | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray] | tuple[np.ndarray, np.ndarray, Line2D]:
     return gca().csd(
@@ -3395,7 +3395,7 @@ def ecdf(
     complementary: bool = False,
     orientation: Literal["vertical", "horizontal"] = "vertical",
     compress: bool = False,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> Line2D:
     return gca().ecdf(
@@ -3429,7 +3429,7 @@ def errorbar(
     capthick: float | None = None,
     elinestyle: LineStyleType | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> ErrorbarContainer:
     return gca().errorbar(
@@ -3466,7 +3466,7 @@ def eventplot(
     alpha: float | Sequence[float] | None = None,
     linestyles: LineStyleType | Sequence[LineStyleType] = "solid",
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> EventCollection:
     return gca().eventplot(
@@ -3485,7 +3485,7 @@ def eventplot(
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.fill)
-def fill(*args, data=None, **kwargs) -> list[Polygon]:
+def fill(*args, data: DataParamType = None, **kwargs) -> list[Polygon]:
     return gca().fill(*args, **({"data": data} if data is not None else {}), **kwargs)
 
 
@@ -3499,7 +3499,7 @@ def fill_between(
     interpolate: bool = False,
     step: Literal["pre", "post", "mid"] | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> FillBetweenPolyCollection:
     return gca().fill_between(
@@ -3524,7 +3524,7 @@ def fill_betweenx(
     step: Literal["pre", "post", "mid"] | None = None,
     interpolate: bool = False,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> FillBetweenPolyCollection:
     return gca().fill_betweenx(
@@ -3600,7 +3600,7 @@ def hexbin(
     marginals: bool = False,
     colorizer: Colorizer | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> PolyCollection:
     __ret = gca().hexbin(
@@ -3649,7 +3649,7 @@ def hist(
     label: str | Sequence[str] | None = None,
     stacked: bool = False,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[
     np.ndarray | list[np.ndarray],
@@ -3686,7 +3686,7 @@ def stairs(
     orientation: Literal["vertical", "horizontal"] = "vertical",
     baseline: float | ArrayLike | None = 0,
     fill: bool = False,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> StepPatch:
     return gca().stairs(
@@ -3712,7 +3712,7 @@ def hist2d(
     cmin: float | None = None,
     cmax: float | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, np.ndarray, QuadMesh]:
     __ret = gca().hist2d(
@@ -3741,7 +3741,7 @@ def hlines(
     linestyles: LineStyleType = "solid",
     label: str = "",
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> LineCollection:
     return gca().hlines(
@@ -3776,7 +3776,7 @@ def imshow(
     filterrad: float = 4.0,
     resample: bool | None = None,
     url: str | None = None,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> AxesImage:
     __ret = gca().imshow(
@@ -3834,7 +3834,7 @@ def magnitude_spectrum(
     sides: Literal["default", "onesided", "twosided"] | None = None,
     scale: Literal["default", "linear", "dB"] | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, Line2D]:
     return gca().magnitude_spectrum(
@@ -3884,7 +3884,7 @@ def pcolor(
     vmin: float | None = None,
     vmax: float | None = None,
     colorizer: Colorizer | None = None,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> Collection:
     __ret = gca().pcolor(
@@ -3915,7 +3915,7 @@ def pcolormesh(
     colorizer: Colorizer | None = None,
     shading: Literal["flat", "nearest", "gouraud", "auto"] | None = None,
     antialiased: bool = False,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> QuadMesh:
     __ret = gca().pcolormesh(
@@ -3945,7 +3945,7 @@ def phase_spectrum(
     pad_to: int | None = None,
     sides: Literal["default", "onesided", "twosided"] | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, Line2D]:
     return gca().phase_spectrum(
@@ -3982,7 +3982,7 @@ def pie(
     *,
     normalize: bool = True,
     hatch: str | Sequence[str] | None = None,
-    data=None,
+    data: DataParamType = None,
 ) -> PieContainer:
     return gca().pie(
         x,
@@ -4035,7 +4035,7 @@ def plot(
     *args: float | ArrayLike | str,
     scalex: bool = True,
     scaley: bool = True,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> list[Line2D]:
     return gca().plot(
@@ -4054,9 +4054,9 @@ def psd(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: (
-        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
-    ) = None,
+    detrend: Literal["none", "mean", "linear"]
+    | Callable[[ArrayLike], ArrayLike]
+    | None = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     pad_to: int | None = None,
@@ -4064,7 +4064,7 @@ def psd(
     scale_by_freq: bool | None = None,
     return_line: bool | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray] | tuple[np.ndarray, np.ndarray, Line2D]:
     return gca().psd(
@@ -4086,7 +4086,7 @@ def psd(
 
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_copy_docstring_and_deprecators(Axes.quiver)
-def quiver(*args, data=None, **kwargs) -> Quiver:
+def quiver(*args, data: DataParamType = None, **kwargs) -> Quiver:
     __ret = gca().quiver(
         *args, **({"data": data} if data is not None else {}), **kwargs
     )
@@ -4120,7 +4120,7 @@ def scatter(
     edgecolors: Literal["face", "none"] | ColorType | Sequence[ColorType] | None = None,
     colorizer: Colorizer | None = None,
     plotnonfinite: bool = False,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> PathCollection:
     __ret = gca().scatter(
@@ -4164,9 +4164,9 @@ def specgram(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: (
-        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
-    ) = None,
+    detrend: Literal["none", "mean", "linear"]
+    | Callable[[ArrayLike], ArrayLike]
+    | None = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     cmap: str | Colormap | None = None,
@@ -4179,7 +4179,7 @@ def specgram(
     vmin: float | None = None,
     vmax: float | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, np.ndarray, AxesImage]:
     __ret = gca().specgram(
@@ -4255,7 +4255,7 @@ def stem(
     bottom: float = 0,
     label: str | None = None,
     orientation: Literal["vertical", "horizontal"] = "vertical",
-    data=None,
+    data: DataParamType = None,
 ) -> StemContainer:
     return gca().stem(
         *args,
@@ -4276,7 +4276,7 @@ def step(
     y: ArrayLike,
     *args,
     where: Literal["pre", "post", "mid"] = "pre",
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> list[Line2D]:
     return gca().step(
@@ -4480,14 +4480,15 @@ def violinplot(
     showmedians: bool = False,
     quantiles: Sequence[float | Sequence[float]] | None = None,
     points: int = 100,
-    bw_method: (
-        Literal["scott", "silverman"] | float | Callable[[GaussianKDE], float] | None
-    ) = None,
+    bw_method: Literal["scott", "silverman"]
+    | float
+    | Callable[[GaussianKDE], float]
+    | None = None,
     side: Literal["both", "low", "high"] = "both",
     facecolor: Sequence[ColorType] | ColorType | None = None,
     linecolor: Sequence[ColorType] | ColorType | None = None,
     *,
-    data=None,
+    data: DataParamType = None,
 ) -> dict[str, Collection]:
     return gca().violinplot(
         dataset,
@@ -4518,7 +4519,7 @@ def vlines(
     linestyles: LineStyleType = "solid",
     label: str = "",
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> LineCollection:
     return gca().vlines(
@@ -4543,7 +4544,7 @@ def xcorr(
     usevlines: bool = True,
     maxlags: int = 10,
     *,
-    data=None,
+    data: DataParamType = None,
     **kwargs,
 ) -> tuple[np.ndarray, np.ndarray, LineCollection | Line2D, Line2D | None]:
     return gca().xcorr(
diff --git a/lib/matplotlib/typing.py b/lib/matplotlib/typing.py
index 87016984da12..7fd9bdeefa8f 100644
--- a/lib/matplotlib/typing.py
+++ b/lib/matplotlib/typing.py
@@ -13,7 +13,7 @@
 from collections.abc import Hashable, Sequence
 import pathlib
 from typing import Any, Literal, TypeAlias, TypeVar, Union
-from collections.abc import Callable
+from collections.abc import Callable, Mapping
 
 from . import path
 from ._enums import JoinStyle, CapStyle
@@ -22,6 +22,9 @@
 from .markers import MarkerStyle
 from .transforms import Bbox, Transform
 
+DataParamType: TypeAlias = Mapping[str, Any] | None
+"""The type of the *data* parameter in plotting functions."""
+
 RGBColorType: TypeAlias = tuple[float, float, float] | str
 """Any RGB color specification accepted by Matplotlib."""
 

From 71facf6ba367854a89d82d601193c683c32f36b7 Mon Sep 17 00:00:00 2001
From: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Date: Fri, 10 Apr 2026 08:36:08 +0200
Subject: [PATCH 2/2] Run boilerplate with current version of black

---
 lib/matplotlib/pyplot.py | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 777bc4877aa9..65b257096cbc 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -3297,8 +3297,9 @@ def cohere(
     NFFT: int = 256,
     Fs: float = 2,
     Fc: int = 0,
-    detrend: Literal["none", "mean", "linear"]
-    | Callable[[ArrayLike], ArrayLike] = mlab.detrend_none,
+    detrend: (
+        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike]
+    ) = mlab.detrend_none,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike = mlab.window_hanning,
     noverlap: int = 0,
     pad_to: int | None = None,
@@ -3355,9 +3356,9 @@ def csd(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: Literal["none", "mean", "linear"]
-    | Callable[[ArrayLike], ArrayLike]
-    | None = None,
+    detrend: (
+        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
+    ) = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     pad_to: int | None = None,
@@ -4054,9 +4055,9 @@ def psd(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: Literal["none", "mean", "linear"]
-    | Callable[[ArrayLike], ArrayLike]
-    | None = None,
+    detrend: (
+        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
+    ) = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     pad_to: int | None = None,
@@ -4164,9 +4165,9 @@ def specgram(
     NFFT: int | None = None,
     Fs: float | None = None,
     Fc: int | None = None,
-    detrend: Literal["none", "mean", "linear"]
-    | Callable[[ArrayLike], ArrayLike]
-    | None = None,
+    detrend: (
+        Literal["none", "mean", "linear"] | Callable[[ArrayLike], ArrayLike] | None
+    ) = None,
     window: Callable[[ArrayLike], ArrayLike] | ArrayLike | None = None,
     noverlap: int | None = None,
     cmap: str | Colormap | None = None,
@@ -4480,10 +4481,9 @@ def violinplot(
     showmedians: bool = False,
     quantiles: Sequence[float | Sequence[float]] | None = None,
     points: int = 100,
-    bw_method: Literal["scott", "silverman"]
-    | float
-    | Callable[[GaussianKDE], float]
-    | None = None,
+    bw_method: (
+        Literal["scott", "silverman"] | float | Callable[[GaussianKDE], float] | None
+    ) = None,
     side: Literal["both", "low", "high"] = "both",
     facecolor: Sequence[ColorType] | ColorType | None = None,
     linecolor: Sequence[ColorType] | ColorType | None = None,