fix: Support pandas ExtensionArray ordering (#6481)

holoviews/core/data/__init__.py

@@ -264,6 +264,8 @@ class Dataset(Element, metaclass=PipelineMeta):
     _vdim_reductions = {}
     _kdim_reductions = {}
 
+    interface: Interface
+
     def __new__(cls, data=None, kdims=None, vdims=None, **kwargs):
         """
         Allows casting a DynamicMap to an Element class like hv.Curve, by applying the

holoviews/core/dimension.py

@@ -3,6 +3,8 @@
 axis or map dimension. Also supplies the Dimensioned abstract
 baseclass for classes that accept Dimension values.
 """
+from __future__ import annotations
+
 import builtins
 import datetime as dt
 import re
@@ -922,7 +924,7 @@ def dimensions(self, selection='all', label=False):
                 if label else dim for dim in dims]
 
 
-    def get_dimension(self, dimension, default=None, strict=False):
+    def get_dimension(self, dimension, default=None, strict=False) -> Dimension | None:
         """Get a Dimension object by name or index.
 
         Args:

holoviews/element/util.py

@@ -1,4 +1,7 @@
+from __future__ import annotations
+
 import itertools
+from typing import TYPE_CHECKING
 
 import numpy as np
 import pandas as pd
@@ -19,6 +22,11 @@
     sort_topologically,
 )
 
+if TYPE_CHECKING:
+    from typing import TypeVar
+
+    Array = TypeVar("Array", np.ndarray, pd.api.extensions.ExtensionArray)
+
 
 def split_path(path):
     """
@@ -126,18 +134,19 @@ class categorical_aggregate2d(Operation):
         The grid interface types to use when constructing the gridded Dataset.""")
 
     @classmethod
-    def _get_coords(cls, obj):
+    def _get_coords(cls, obj: Dataset):
         """
         Get the coordinates of the 2D aggregate, maintaining the correct
         sorting order.
         """
         xdim, ydim = obj.dimensions(label=True)[:2]
         xcoords = obj.dimension_values(xdim, False)
         ycoords = obj.dimension_values(ydim, False)
+
         if xcoords.dtype.kind not in 'SUO':
-            xcoords = np.sort(xcoords)
+            xcoords = sort_arr(xcoords)
         if ycoords.dtype.kind not in 'SUO':
-            return xcoords, np.sort(ycoords)
+            return xcoords, sort_arr(ycoords)
 
         # Determine global orderings of y-values using topological sort
         grouped = obj.groupby(xdim, container_type=dict,
@@ -149,19 +158,18 @@ def _get_coords(cls, obj):
             if len(vals) == 1:
                 orderings[vals[0]] = [vals[0]]
             else:
-                for i in range(len(vals)-1):
-                    p1, p2 = vals[i:i+2]
+                for p1, p2 in zip(vals[:-1], vals[1:]):
                     orderings[p1] = [p2]
             if sort:
                 if vals.dtype.kind in ('i', 'f'):
                     sort = (np.diff(vals)>=0).all()
                 else:
-                    sort = np.array_equal(np.sort(vals), vals)
+                    sort = np.array_equal(sort_arr(vals), vals)
         if sort or one_to_one(orderings, ycoords):
-            ycoords = np.sort(ycoords)
+            ycoords = sort_arr(ycoords)
         elif not is_cyclic(orderings):
             coords = list(itertools.chain(*sort_topologically(orderings)))
-            ycoords = coords if len(coords) == len(ycoords) else np.sort(ycoords)
+            ycoords = coords if len(coords) == len(ycoords) else sort_arr(ycoords)
         return np.asarray(xcoords), np.asarray(ycoords)
 
     def _aggregate_dataset(self, obj):
@@ -332,3 +340,9 @@ def connect_edges(graph):
         end = end_ds.array(end_ds.kdims[:2])
         paths.append(np.array([start[0], end[0]]))
     return paths
+
+
+def sort_arr(arr: Array) -> Array:
+    if isinstance(arr, pd.api.extensions.ExtensionArray):
+        return arr[arr.argsort()]
+    return np.sort(arr)

holoviews/tests/plotting/bokeh/test_barplot.py

@@ -351,6 +351,27 @@ def test_bars_not_continuous_data_list_custom_width(self):
         plot = bokeh_renderer.get_plot(bars)
         assert plot.handles["glyph"].width == 1
 
+    def test_bars_categorical_order(self):
+        cells_dtype = pd.CategoricalDtype(
+            pd.array(["~1M", "~10M", "~100M"], dtype="string"),
+            ordered=True,
+        )
+        df = pd.DataFrame(dict(
+            cells=cells_dtype.categories.astype(cells_dtype),
+            time=pd.array([2.99, 18.5, 835.2]),
+            function=pd.array(["read", "read", "read"]),
+        ))
+
+        bars = Bars(df, ["function", "cells"], ["time"])
+        plot = bokeh_renderer.get_plot(bars)
+        x_factors = plot.handles["x_range"].factors
+
+        np.testing.assert_equal(x_factors, [
+            ("read", "~1M"),
+            ("read", "~10M"),
+            ("read", "~100M"),
+        ])
+
     def test_bars_group(self):
         samples = 100