bar3d no longer allows default colors

[matthew-brett]

For matplotlib 2.0.0b3 on OSX 10.9, homebrew Python 3.5, matplotlib installed via pip.

This file:

import numpy as np
from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
x = np.arange(20)
y = np.arange(20)
x2d, y2d = np.meshgrid(x, y)
x2d, y2d = x2d.ravel(), y2d.ravel()
z = x2d + y2d
ax.bar3d(x2d, y2d, x2d * 0, 1, 1, z)
plt.show()

generates the following error:

Traceback (most recent call last):
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/matplotlib/colors.py", line 133, in to_rgba
    rgba = _colors_full_map.cache[c, alpha]
KeyError: (None, None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/matplotlib/colors.py", line 183, in _to_rgba_no_colorcycle
    c = tuple(map(float, c))
TypeError: 'NoneType' object is not iterable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "bar_thing.py", line 12, in <module>
    ax.bar3d(x2d, y2d, x2d * 0, 1, 1, z)
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/mpl_toolkits/mplot3d/axes3d.py", line 2459, in bar3d
    sfacecolors = self._shade_colors(facecolors, normals)
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/mpl_toolkits/mplot3d/axes3d.py", line 1717, in _shade_colors
    color = mcolors.to_rgba_array(color)
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/matplotlib/colors.py", line 228, in to_rgba_array
    result[i] = to_rgba(cc, alpha)
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/matplotlib/colors.py", line 135, in to_rgba
    rgba = _to_rgba_no_colorcycle(c, alpha)
  File "/Users/mb312/Library/Python/3.5/lib/python/site-packages/matplotlib/colors.py", line 185, in _to_rgba_no_colorcycle
    raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
ValueError: Invalid RGBA argument: None

Adding color='b' to the arguments to ax.bar3d fixes the error.

Matplotlib 1.5.2 on the same platform, via pip, generates no error.

Maybe there's a bug in the default color handling?

[QuLogic]

Bisect points to e524354 (@tacaswell) as the first bad commit:

commit e52435406d0a7a8a8a44a485a753d9ed3a069adc
Author: Thomas A Caswell <tcaswell@gmail.com>
Date:   Thu Apr 28 07:22:21 2016 -0700

    API/ENH: Color cycle handling

    API/ENH: Color cycle handling

:040000 040000 7c0610291ba704cded529513d481fb2bf6f0aedc c181faa9e953b86c548d1f6d8809009498bbcb9b M  examples
:040000 040000 0ebc0950e69c2bbdac4cdb99bd6c4af687d02823 d60a968c83f188c5516eb3447849cdb50bfa54ac M  lib
:100644 100644 f7aa486f09149f0fe499a3a0601b2b95ae9666dc 83ed82e1b930c0ce0512e3c1cdf6c68d2de70b54 M  matplotlibrc.template

[matthew-brett]

Kudos for your bisecting skills!

[tacaswell]

I have a patch