Unicode issue in matplotlib.dates #7630
Description
The import of __future__.unicode_literals in matplotlib.dates causes an error when calling datetime.datetime.tzname() on a datetime created with tzinfo=matplotlib.dates.UTC:
>>> import matplotlib.dates
>>> import datetime
>>> dt = datetime.datetime(2000,1,1, tzinfo=matplotlib.dates.UTC)
>>> dt.tzname()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: tzinfo.tzname() must return None or a string, not 'unicode'
This causes issues when plotting with a date formatter:
>>> import matplotlib.pyplot as plt
>>> import matplotlib.dates
>>> plt.plot([700000], [0])
[<matplotlib.lines.Line2D object at 0x7fe41dbb4050>]
>>> plt.gca().xaxis.set_major_formatter(matplotlib.dates.DateFormatter('%Z'))
>>> plt.show()
...
File .../lib/python2.7/site-packages/matplotlib/dates.py", line 589, in strftime
return cbook.unicode_safe(dt.strftime(fmt))
TypeError: tzinfo.tzname() must return None or a string, not 'unicode'
(I've omitted most of the call stack)
Matplotlib 1.5.3, Python 2.7.12, Linux
Installed from source
The issue doesn't exist in Matplotlib 1.3.1