FIX: do not replace the Axes._children list object

tacaswell · tacaswell · commit 0f4ec9ae7390 · 2022-12-09T12:19:03.000-05:00
Each Artist keeps a reference to `Axes._children.remove` as `art._remove_method`. If we replace the `_children` instance on the Axes with a different list instance the Artists will not be updated and their remove method will refer to the wrong list. This will cause subsequent failures on the next draw because on remove we reset the `art.axes` and `art.figure` to None. xref https://discourse.matplotlib.org/t/host-subplot-and-artist-remove/23374
diff --git a/lib/mpl_toolkits/axes_grid1/parasite_axes.py b/lib/mpl_toolkits/axes_grid1/parasite_axes.py
@@ -136,7 +136,7 @@ def draw(self, renderer):
             self._children.extend(ax.get_children())
 
         super().draw(renderer)
-        self._children = self._children[:orig_children_len]
+        del self._children[orig_children_len:]
 
     def clear(self):
         super().clear()
diff --git a/lib/mpl_toolkits/axes_grid1/tests/test_axes_grid1.py b/lib/mpl_toolkits/axes_grid1/tests/test_axes_grid1.py
@@ -684,3 +684,14 @@ def test_imagegrid():
     im = ax.imshow([[1, 2]], norm=mpl.colors.LogNorm())
     cb = ax.cax.colorbar(im)
     assert isinstance(cb.locator, mticker.LogLocator)
+
+
+def test_removal():
+    import matplotlib.pyplot as plt
+    import mpl_toolkits.axisartist as AA
+    fig = plt.figure()
+    ax = host_subplot(111, axes_class=AA.Axes, figure=fig)
+    col = ax.fill_between(range(5), 0, range(5))
+    fig.canvas.draw()
+    col.remove()
+    fig.canvas.draw()
