Add RuntimeWarning guard.

oscargus · oscargus · commit 4cb1dbdb83e8 · 2022-03-10T11:25:13.000+01:00
diff --git a/lib/mpl_toolkits/mplot3d/proj3d.py b/lib/mpl_toolkits/mplot3d/proj3d.py
@@ -17,11 +17,13 @@ def _line2d_seg_dist(p1, p2, p0):
     and intersection point lies within segment if u is between 0 and 1
     """
 
-    x21 = p2[0] - p1[0]
-    y21 = p2[1] - p1[1]
     x01 = np.asarray(p0[0]) - p1[0]
     y01 = np.asarray(p0[1]) - p1[1]
+    if p1 == p2:  # Avoid RuntimeWarning
+        return np.hypot(x01, y01)
 
+    x21 = p2[0] - p1[0]
+    y21 = p2[1] - p1[1]
     u = (x01*x21 + y01*y21) / (x21**2 + y21**2)
     u = np.clip(u, 0, 1)
     d = np.hypot(x01 - u*x21, y01 - u*y21)
diff --git a/lib/mpl_toolkits/tests/test_mplot3d.py b/lib/mpl_toolkits/tests/test_mplot3d.py
@@ -1002,6 +1002,14 @@ def test_lines_dists():
     ax.set_ylim(0, 300)
 
 
+def test_lines_dists_nowarning():
+    # Smoke test to see that no RuntimeWarning is emitted when two first
+    # arguments are the same, see GH#22624
+    p0 = (10, 30)
+    p1 = (20, 150)
+    proj3d._line2d_seg_dist(p0, p0, p1)
+
+
 def test_autoscale():
     fig, ax = plt.subplots(subplot_kw={"projection": "3d"})
     ax.margins(x=0, y=.1, z=.2)
