Using ProgressBar as iterator from empty iterable causes traceback #36

progressbar==2.3
Ubuntu 13.04


So this works:

for n in progressbar.ProgressBar()([1]):
    print n

It will print 1 and all the progress information as expected.

But

for n in progressbar.ProgressBar()([]):
    print n

gives traceback as follows:


AttributeError                            Traceback (most recent call last)
<ipython-input-4-bf738fc09ad4> in <module>()
----> 1 for n in progressbar.ProgressBar()([]):
      2     print n
      3 

/home/tcorbettclark/.virtualenvs/ice/local/lib/python2.7/site-packages/progressb
ar/__init__.pyc in __next__(self)
    182             return value
    183         except StopIteration:
--> 184             self.finish()
    185             raise
    186 

/home/tcorbettclark/.virtualenvs/ice/local/lib/python2.7/site-packages/progressb
ar/__init__.pyc in finish(self)
    318 
    319         self.finished = True
--> 320         self.update(self.maxval)
    321         self.fd.write('\n')
    322         if self.signal_set:

/home/tcorbettclark/.virtualenvs/ice/local/lib/python2.7/site-packages/progressb
ar/__init__.pyc in update(self, value)
    274 
    275 
--> 276         if not self._need_update(): return
    277         if self.start_time is None:
    278             raise RuntimeError('You must call "start" before calling "update"')

/home/tcorbettclark/.virtualenvs/ice/local/lib/python2.7/site-packages/progressb
ar/__init__.pyc in _need_update(self)
    249     def _need_update(self):
    250         'Returns whether the ProgressBar should redraw the line.'
--> 251         if self.currval >= self.next_update or self.finished: return 
True
    252 
    253         delta = time.time() - self.last_update_time

AttributeError: next_update