ENH: warn when silently ignoring log keywords in PiePlot (#55890)

* ENH: warn when silently ignoring log keywords in PiePlot

* pyright fixup

* mypy fixup

* troubleshoot mypy

Author: jbrockmendel

pandas/plotting/_matplotlib/core.py

@@ -159,6 +159,14 @@ def __init__(
         layout=None,
         include_bool: bool = False,
         column: IndexLabel | None = None,
+        *,
+        logx: bool | None | Literal["sym"] = False,
+        logy: bool | None | Literal["sym"] = False,
+        loglog: bool | None | Literal["sym"] = False,
+        mark_right: bool = True,
+        stacked: bool = False,
+        label: Hashable | None = None,
+        style=None,
         **kwds,
     ) -> None:
         import matplotlib.pyplot as plt
@@ -230,13 +238,13 @@ def __init__(
         self.legend_handles: list[Artist] = []
         self.legend_labels: list[Hashable] = []
 
-        self.logx = kwds.pop("logx", False)
-        self.logy = kwds.pop("logy", False)
-        self.loglog = kwds.pop("loglog", False)
-        self.label = kwds.pop("label", None)
-        self.style = kwds.pop("style", None)
-        self.mark_right = kwds.pop("mark_right", True)
-        self.stacked = kwds.pop("stacked", False)
+        self.logx = type(self)._validate_log_kwd("logx", logx)
+        self.logy = type(self)._validate_log_kwd("logy", logy)
+        self.loglog = type(self)._validate_log_kwd("loglog", loglog)
+        self.label = label
+        self.style = style
+        self.mark_right = mark_right
+        self.stacked = stacked
 
         # ax may be an Axes object or (if self.subplots) an ndarray of
         #  Axes objects
@@ -292,6 +300,22 @@ def _validate_sharex(sharex: bool | None, ax, by) -> bool:
             raise TypeError("sharex must be a bool or None")
         return bool(sharex)
 
+    @classmethod
+    def _validate_log_kwd(
+        cls,
+        kwd: str,
+        value: bool | None | Literal["sym"],
+    ) -> bool | None | Literal["sym"]:
+        if (
+            value is None
+            or isinstance(value, bool)
+            or (isinstance(value, str) and value == "sym")
+        ):
+            return value
+        raise ValueError(
+            f"keyword '{kwd}' should be bool, None, or 'sym', not '{value}'"
+        )
+
     @final
     @staticmethod
     def _validate_subplots_kwarg(
@@ -556,14 +580,6 @@ def _axes_and_fig(self) -> tuple[Sequence[Axes], Figure]:
 
         axes = flatten_axes(axes)
 
-        valid_log = {False, True, "sym", None}
-        input_log = {self.logx, self.logy, self.loglog}
-        if input_log - valid_log:
-            invalid_log = next(iter(input_log - valid_log))
-            raise ValueError(
-                f"Boolean, None and 'sym' are valid options, '{invalid_log}' is given."
-            )
-
         if self.logx is True or self.loglog is True:
             [a.set_xscale("log") for a in axes]
         elif self.logx == "sym" or self.loglog == "sym":
@@ -1334,7 +1350,12 @@ def _make_plot(self, fig: Figure):
                 cbar.ax.set_yticklabels(self.data[c].cat.categories)
 
         if label is not None:
-            self._append_legend_handles_labels(scatter, label)
+            self._append_legend_handles_labels(
+                # error: Argument 2 to "_append_legend_handles_labels" of
+                # "MPLPlot" has incompatible type "Hashable"; expected "str"
+                scatter,
+                label,  # type: ignore[arg-type]  # pyright: ignore[reportGeneralTypeIssues]
+            )
 
         errors_x = self._get_errorbars(label=x, index=0, yerr=False)
         errors_y = self._get_errorbars(label=y, index=0, xerr=False)
@@ -1999,10 +2020,21 @@ def __init__(self, data, kind=None, **kwargs) -> None:
         if (data < 0).any().any():
             raise ValueError(f"{self._kind} plot doesn't allow negative values")
         MPLPlot.__init__(self, data, kind=kind, **kwargs)
-        self.grid = False
-        self.logy = False
-        self.logx = False
-        self.loglog = False
+
+    @classmethod
+    def _validate_log_kwd(
+        cls,
+        kwd: str,
+        value: bool | None | Literal["sym"],
+    ) -> bool | None | Literal["sym"]:
+        super()._validate_log_kwd(kwd=kwd, value=value)
+        if value is not False:
+            warnings.warn(
+                f"PiePlot ignores the '{kwd}' keyword",
+                UserWarning,
+                stacklevel=find_stack_level(),
+            )
+        return False
 
     def _validate_color_args(self, color, colormap) -> None:
         # TODO: warn if color is passed and ignored?

pandas/tests/plotting/frame/test_frame.py

@@ -333,10 +333,14 @@ def test_invalid_logscale(self, input_param):
         # GH: 24867
         df = DataFrame({"a": np.arange(100)}, index=np.arange(100))
 
-        msg = "Boolean, None and 'sym' are valid options, 'sm' is given."
+        msg = f"keyword '{input_param}' should be bool, None, or 'sym', not 'sm'"
         with pytest.raises(ValueError, match=msg):
             df.plot(**{input_param: "sm"})
 
+        msg = f"PiePlot ignores the '{input_param}' keyword"
+        with tm.assert_produces_warning(UserWarning, match=msg):
+            df.plot.pie(subplots=True, **{input_param: True})
+
     def test_xcompat(self):
         df = tm.makeTimeDataFrame()
         ax = df.plot(x_compat=True)