Fix #5572: Allow passing empty range to broken_barh

lib/matplotlib/axes/_axes.py

@@ -2339,8 +2339,16 @@ def broken_barh(self, xranges, yrange, **kwargs):
         .. plot:: mpl_examples/pylab_examples/broken_barh.py
         """
         # process the unit information
-        self._process_unit_info(xdata=xranges[0],
-                                ydata=yrange[0],
+        if len(xranges):
+            xdata = six.next(iter(xranges))
+        else:
+            xdata = None
+        if len(yrange):
+            ydata = six.next(iter(yrange))
+        else:
+            ydata = None
+        self._process_unit_info(xdata=xdata,
+                                ydata=ydata,
                                 kwargs=kwargs)
         xranges = self.convert_xunits(xranges)
         yrange = self.convert_yunits(yrange)

lib/matplotlib/tests/test_axes.py

@@ -4241,6 +4241,12 @@ def _helper_y(ax):
     assert assert_array_equal(ax_lst[0][1].get_xlim(), orig_xlim)
 
 
+@cleanup
+def test_broken_barh_empty():
+    fig, ax = plt.subplots()
+    ax.broken_barh([], (.1, .5))
+
+
 if __name__ == '__main__':
     import nose
     import sys