Merge pull request #13658 from meeseeksmachine/auto-backport-of-pr-13652-on-v3.1.x

timhoffm · web-flow · commit 090410e357f3 · 2019-03-13T00:06:07.000+01:00
Backport PR #13652 on branch v3.1.x (Fix empty FancyArrow crash)
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -1269,7 +1269,7 @@ def __init__(self, x, y, dx, dy, width=0.001, length_includes_head=False,
         else:
             length = distance + head_length
         if not length:
-            verts = []  # display nothing if empty
+            verts = np.empty([0, 2])  # display nothing if empty
         else:
             # start by drawing horizontal arrow, point at (0,0)
             hw, hl, hs, lw = head_width, head_length, overhang, width
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -379,6 +379,12 @@ def test_arrow_simple():
                  head_length=theta / 10)
 
 
+def test_arrow_empty():
+    _, ax = plt.subplots()
+    # Create an empty FancyArrow
+    ax.arrow(0, 0, 0, 0, head_length=0)
+
+
 def test_annotate_default_arrow():
     # Check that we can make an annotation arrow with only default properties.
     fig, ax = plt.subplots()
