Fix NameError: name '_rl' is not defined

IPython/utils/rlineimpl.py

@@ -1,74 +1,74 b''
 # -*- coding: utf-8 -*-
 """ Imports and provides the 'correct' version of readline for the platform.
 
 Readline is used throughout IPython as::
 
     import IPython.utils.rlineimpl as readline
 
 In addition to normal readline stuff, this module provides have_readline
 boolean and _outputfile variable used in IPython.utils.
 """
 
 import sys
 import warnings
 
 _rlmod_names = ['gnureadline', 'readline']
 
 have_readline = False
 for _rlmod_name in _rlmod_names:
     try:
         # import readline as _rl
         _rl = __import__(_rlmod_name)
         # from readline import *
         globals().update({k:v for k,v in _rl.__dict__.items() if not k.startswith('_')})
     except ImportError:
         pass
     else:
         have_readline = True
         break
 
-if sys.platform == 'win32' or sys.platform == 'cli':
+if have_readline and (sys.platform == 'win32' or sys.platform == 'cli'):
     try:
         _outputfile=_rl.GetOutputFile()
     except AttributeError:
         warnings.warn("Failed GetOutputFile")
         have_readline = False
 
 # Test to see if libedit is being used instead of GNU readline.
 # Thanks to Boyd Waters for the original patch.
 uses_libedit = False
 
 if have_readline:
     # Official Python docs state that 'libedit' is in the docstring for libedit readline:
     uses_libedit = _rl.__doc__ and 'libedit' in _rl.__doc__
     # Note that many non-System Pythons also do not use proper readline,
     # but do not report libedit at all, nor are they linked dynamically against libedit.
     # known culprits of this include: EPD, Fink
     # There is not much we can do to detect this, until we find a specific failure
     # case, rather than relying on the readline module to self-identify as broken.
 
 if uses_libedit and sys.platform == 'darwin':
     _rl.parse_and_bind("bind ^I rl_complete")
     warnings.warn('\n'.join(['', "*"*78,
         "libedit detected - readline will not be well behaved, including but not limited to:",
         "   * crashes on tab completion",
         "   * incorrect history navigation",
         "   * corrupting long-lines",
         "   * failure to wrap or indent lines properly",
         "It is highly recommended that you install gnureadline, which is installable with:",
         "     pip install gnureadline",
         "*"*78]),
         RuntimeWarning)
 
 # the clear_history() function was only introduced in Python 2.4 and is
 # actually optional in the readline API, so we must explicitly check for its
 # existence.  Some known platforms actually don't have it.  This thread:
 # http://mail.python.org/pipermail/python-dev/2003-August/037845.html
 # has the original discussion.
 
 if have_readline:
     try:
         _rl.clear_history
     except AttributeError:
         def clear_history(): pass
         _rl.clear_history = clear_history