swev-id: matplotlib__matplotlib-24627 - detach artist parents after cla/clf

lib/matplotlib/axes/_base.py

@@ -1307,6 +1307,15 @@ def __clear(self):
         self._get_lines = _process_plot_var_args(self)
         self._get_patches_for_fill = _process_plot_var_args(self, 'fill')
 
+        legend = getattr(self, "legend_", None)
+        if legend is not None:
+            legend.remove()
+
+        for child in list(getattr(self, "_children", ())):
+            if child is legend:
+                continue
+            child.remove()
+
         self._gridOn = mpl.rcParams['axes.grid']
         self._children = []
         self._mouseover_set = _OrderedSet()

lib/matplotlib/figure.py

@@ -947,7 +947,19 @@ def clear(self, keep_observers=False):
 
         for ax in tuple(self.axes):  # Iterate over the copy.
             ax.clear()
-            self.delaxes(ax)  # Remove ax from self._axstack.
+            ax.remove()
+
+        for artist_list in (
+                self.artists,
+                self.lines,
+                self.patches,
+                self.texts,
+                self.images,
+                self.legends):
+            for artist in list(artist_list):
+                artist.remove()
+                if getattr(artist, "figure", None) is not None:
+                    artist.figure = None
 
         self.artists = []
         self.lines = []

lib/matplotlib/tests/test_artist.py

@@ -214,6 +214,41 @@ def test_remove():
     assert ax.stale
 
 
+@pytest.mark.backend("Agg")
+def test_cla_unsets_artist_axes():
+    fig, ax = plt.subplots()
+    line, = ax.plot([0, 1], [0, 1])
+    patch = ax.add_patch(mpatches.Rectangle((0, 0), 1, 1))
+    image = ax.imshow(np.arange(4).reshape(2, 2))
+    text = ax.text(0.5, 0.5, "hi")
+    collection = ax.scatter([0], [0])
+    legend = ax.legend([line], ["line"])
+
+    ax.cla()
+
+    for artist in (line, patch, image, text, collection, legend):
+        assert artist.axes is None
+
+
+@pytest.mark.backend("Agg")
+def test_clf_unsets_figure_and_axes_parents():
+    fig, ax = plt.subplots()
+    line, = ax.plot([0, 1], [0, 1])
+    image = ax.imshow(np.arange(4).reshape(2, 2))
+    fig_text = fig.text(0.5, 0.5, "hi")
+    fig_legend = fig.legend([line], ["line"])
+    colorbar = fig.colorbar(image, ax=ax)
+
+    fig.clf()
+
+    assert fig.axes == []
+    assert line.axes is None
+    assert image.axes is None
+    assert fig_text.figure is None
+    assert fig_legend.figure is None
+    assert colorbar.ax.figure is None
+
+
 @image_comparison(["default_edges.png"], remove_text=True, style='default')
 def test_default_edges():
     # Remove this line when this test image is regenerated.