Merge pull request matplotlib#8037 from tacaswell/fix_errorbar_color_…

…cycle

[MRG+1] FIX: in errorbar discard any kwargs which have None value

lib/matplotlib/axes/_axes.py

@@ -2798,6 +2798,9 @@ def errorbar(self, x, y, yerr=None, xerr=None,
         .. plot:: mpl_examples/statistics/errorbar_demo.py
         """
         kwargs = cbook.normalize_kwargs(kwargs, _alias_map)
+        # anything that comes in as 'None', drop so the default thing
+        # happens down stream
+        kwargs = {k: v for k, v in kwargs.items() if v is not None}
         kwargs.setdefault('zorder', 2)
 
         if errorevery < 1:

lib/matplotlib/tests/test_axes.py

@@ -2365,6 +2365,22 @@ def test_errorbar():
     ax.set_title("Simplest errorbars, 0.2 in x, 0.4 in y")
 
 
+@cleanup
+def test_errorbar_colorcycle():
+
+    f, ax = plt.subplots()
+    x = np.arange(10)
+    y = 2*x
+
+    e1, _, _ = ax.errorbar(x, y, c=None)
+    e2, _, _ = ax.errorbar(x, 2*y, c=None)
+    ln1, = ax.plot(x, 4*y)
+
+    assert mcolors.to_rgba(e1.get_color()) == mcolors.to_rgba('C0')
+    assert mcolors.to_rgba(e2.get_color()) == mcolors.to_rgba('C1')
+    assert mcolors.to_rgba(ln1.get_color()) == mcolors.to_rgba('C2')
+
+
 @cleanup
 def test_errorbar_shape():
     fig = plt.figure()