Merge pull request matplotlib#25794 from MichaelTheFear/raise_on_plural_scatter

Raise on plural scatter

Author: timhoffm

lib/matplotlib/axes/_axes.py

@@ -4595,6 +4595,18 @@ def scatter(self, x, y, s=None, c=None, marker=None, cmap=None, norm=None,
           size matches the size of *x* and *y*.
 
         """
+        # add edgecolors and linewidths to kwargs so they
+        # can be processed by normailze_kwargs
+        if edgecolors is not None:
+            kwargs.update({'edgecolors': edgecolors})
+        if linewidths is not None:
+            kwargs.update({'linewidths': linewidths})
+
+        kwargs = cbook.normalize_kwargs(kwargs, mcoll.Collection)
+        # re direct linewidth and edgecolor so it can be
+        # further processed by the rest of the function
+        linewidths = kwargs.pop('linewidth', None)
+        edgecolors = kwargs.pop('edgecolor', None)
         # Process **kwargs to handle aliases, conflicts with explicit kwargs:
         x, y = self._process_unit_info([("x", x), ("y", y)], kwargs)
         # np.ma.ravel yields an ndarray, not a masked array,

lib/matplotlib/tests/test_axes.py

@@ -2746,6 +2746,27 @@ def test_scatter_linewidths(self):
         assert_array_equal(pc.get_linewidths(),
                            [*range(1, 5), mpl.rcParams['lines.linewidth']])
 
+    def test_scatter_singular_plural_arguments(self):
+
+        with pytest.raises(TypeError,
+                           match="Got both 'linewidth' and 'linewidths',\
+ which are aliases of one another"):
+            plt.scatter([1, 2, 3], [1, 2, 3], linewidths=[0.5, 0.4, 0.3], linewidth=0.2)
+
+        with pytest.raises(TypeError,
+                           match="Got both 'edgecolor' and 'edgecolors',\
+ which are aliases of one another"):
+            plt.scatter([1, 2, 3], [1, 2, 3],
+                        edgecolors=["#ffffff", "#000000", "#f0f0f0"],
+                          edgecolor="#ffffff")
+
+        with pytest.raises(TypeError,
+                           match="Got both 'facecolors' and 'facecolor',\
+ which are aliases of one another"):
+            plt.scatter([1, 2, 3], [1, 2, 3],
+                        facecolors=["#ffffff", "#000000", "#f0f0f0"],
+                            facecolor="#ffffff")
+
 
 def _params(c=None, xsize=2, *, edgecolors=None, **kwargs):
     return (c, edgecolors, kwargs if kwargs is not None else {}, xsize)