FIX: fix passing empty lists to errorbar xerr/yerr

tacaswell · tacaswell · commit a4e3694863ed · 2015-12-22T12:54:12.000-05:00
closes #5641
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -2879,7 +2879,7 @@ def xywhere(xs, ys, mask):
 
         if xerr is not None:
             if (iterable(xerr) and len(xerr) == 2 and
-                iterable(xerr[0]) and iterable(xerr[1])):
+                    iterable(xerr[0]) and iterable(xerr[1])):
                 # using list comps rather than arrays to preserve units
                 left = [thisx - thiserr for (thisx, thiserr)
                         in cbook.safezip(x, xerr[0])]
@@ -2889,9 +2889,11 @@ def xywhere(xs, ys, mask):
                 # Check if xerr is scalar or symmetric. Asymmetric is handled
                 # above. This prevents Nx2 arrays from accidentally
                 # being accepted, when the user meant the 2xN transpose.
-                if not (len(xerr) == 1 or
-                        (len(xerr) == len(x) and not (
-                            iterable(xerr[0]) and len(xerr[0]) > 1))):
+                # special case for empty lists
+                if len(xerr) and not (len(xerr) == 1 or
+                                      (len(xerr) == len(x) and not (
+                                          iterable(xerr[0]) and
+                                          len(xerr[0]) > 1))):
                     raise ValueError("xerr must be a scalar, the same "
                                      "dimensions as x, or 2xN.")
                 # using list comps rather than arrays to preserve units
@@ -2953,9 +2955,10 @@ def xywhere(xs, ys, mask):
                          in cbook.safezip(y, yerr[1])]
             else:
                 # Check for scalar or symmetric, as in xerr.
-                if not (len(yerr) == 1 or
-                        (len(yerr) == len(y) and not (
-                            iterable(yerr[0]) and len(yerr[0]) > 1))):
+                if len(yerr) and not (len(yerr) == 1 or
+                                      (len(yerr) == len(y) and not (
+                                          iterable(yerr[0]) and
+                                          len(yerr[0]) > 1))):
                     raise ValueError("yerr must be a scalar, the same "
                                      "dimensions as y, or 2xN.")
                 # using list comps rather than arrays to preserve units
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -3,7 +3,7 @@
 
 import six
 from six.moves import xrange
-
+from itertools import chain
 import io
 
 from nose.tools import assert_equal, assert_raises, assert_false, assert_true
@@ -13,6 +13,7 @@
 import numpy as np
 from numpy import ma
 from numpy import arange
+from cycler import cycler
 
 import matplotlib
 from matplotlib.testing.decorators import image_comparison, cleanup
@@ -4093,6 +4094,42 @@ def test_violin_point_mass():
     plt.violinplot(np.array([0, 0]))
 
 
+def _eb_succes_helper(ax, x, y, xerr=None, yerr=None):
+    eb = ax.errorbar(x, y, xerr=xerr, yerr=yerr)
+    eb.remove()
+
+
+@cleanup
+def test_errorbar_inputs_shotgun():
+    base_xy = cycler('x', [np.arange(5)]) + cycler('y', [np.ones((5, ))])
+    err_cycler = cycler('err', [1,
+                                [1, 1, 1, 1, 1],
+                                [[1, 1, 1, 1, 1],
+                                 [1, 1, 1, 1, 1]],
+                                np.ones(5),
+                                np.ones((2, 5)),
+                                None
+                                ])
+    xerr_cy = cycler('xerr', err_cycler)
+    yerr_cy = cycler('yerr', err_cycler)
+
+    empty = ((cycler('x', [[]]) + cycler('y', [[]])) *
+             cycler('xerr', [[], None]) * cycler('yerr', [[], None]))
+    xerr_only = base_xy * xerr_cy
+    yerr_only = base_xy * yerr_cy
+    both_err = base_xy * yerr_cy * xerr_cy
+
+    test_cyclers = xerr_only, yerr_only, both_err, empty
+
+    ax = plt.gca()
+    # should do this as a generative test, but @cleanup seems to break that
+    # for p in chain(*test_cyclers):
+    #     yield (_eb_succes_helper, ax) + tuple(p.get(k, None) for
+    #                                          k in ['x', 'y', 'xerr', 'yerr'])
+    for p in chain(*test_cyclers):
+        _eb_succes_helper(ax, **p)
+
+
 @cleanup
 def test_remove_shared_axes():
 
@@ -4137,6 +4174,9 @@ def _helper_y(ax):
     ax.set_xlim(0, 5)
     assert assert_array_equal(ax_lst[0][1].get_xlim(), orig_xlim)
 
+
+
+
 if __name__ == '__main__':
     import nose
     import sys
