Merge pull request #18465 from anntzer/histstackedbottom

timhoffm · web-flow · commit 687fd1277bc7 · 2020-09-13T17:40:37.000+02:00
Don't modify bottom argument in place in stacked histograms.
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -6665,7 +6665,7 @@ def hist(self, x, bins=None, range=None, density=False, weights=None,
                                  color=c, **{bottom_kwarg: bottom})
                 patches.append(patch)
                 if stacked:
-                    bottom[:] = m
+                    bottom = m
                 boffset += dw
 
         elif histtype.startswith('step'):
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -3532,6 +3532,12 @@ def test_hist_stacked_bar():
     ax.legend(loc='upper right', bbox_to_anchor=(1.0, 1.0), ncol=1)
 
 
+def test_hist_barstacked_bottom_unchanged():
+    b = np.array([10, 20])
+    plt.hist([[0, 1], [0, 1]], 2, histtype="barstacked", bottom=b)
+    assert b.tolist() == [10, 20]
+
+
 def test_hist_emptydata():
     fig = plt.figure()
     ax = fig.add_subplot(111)
