check history length before attempting to access old members. Closes #189

IPython/iplib.py

@@ -6,7 +6,7 b' Requires Python 2.3 or newer.'
 
 This file contains all the classes and helper functions specific to IPython.
 
-$Id: iplib.py 2914 2007-12-31 12:53:16Z vivainio $
+$Id: iplib.py 2915 2007-12-31 13:05:11Z vivainio $
 """
 
 #*****************************************************************************
@@ -2092,10 +2092,11 b' want to merge them back into the new files.""" % locals()'
                 if self.has_readline: # and some config option is set?
                     try:
                         histlen = self.readline.get_current_history_length()
-                        newhist = self.input_hist_raw[-1].rstrip()
-                        self.readline.remove_history_item(histlen-1)
-                        self.readline.replace_history_item(histlen-2,
-                                        newhist.encode(self.stdin_encoding))
+                        if histlen > 1:
+                            newhist = self.input_hist_raw[-1].rstrip()
+                            self.readline.remove_history_item(histlen-1)
+                            self.readline.replace_history_item(histlen-2,
+                                            newhist.encode(self.stdin_encoding))
                     except AttributeError:
                         pass # re{move,place}_history_item are new in 2.4.                
             else: