Handle string exceptions.

IPython/kernel/core/traceback_trap.py

@@ -1,80 +1,85 b''
 # encoding: utf-8
 
 """Object to manage sys.excepthook()."""
 
 __docformat__ = "restructuredtext en"
 
 #-------------------------------------------------------------------------------
 #  Copyright (C) 2008  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-------------------------------------------------------------------------------
 
 #-------------------------------------------------------------------------------
 # Imports
 #-------------------------------------------------------------------------------
 import sys
+from traceback import format_list
 
 class TracebackTrap(object):
     """ Object to trap and format tracebacks.
     """
 
     def __init__(self, formatters=None):
         # A list of formatters to apply.
         if formatters is None:
             formatters = []
         self.formatters = formatters
 
         # All of the traceback information provided to sys.excepthook().
         self.args = None
 
         # The previous hook before we replace it.
         self.old_hook = None
 
 
     def hook(self, *args):
         """ This method actually implements the hook.
         """
         self.args = args
 
     def set(self):
         """ Set the hook.
         """
 
         if sys.excepthook is not self.hook:
             self.old_hook = sys.excepthook
             sys.excepthook = self.hook
 
     def unset(self):
         """ Unset the hook.
         """
 
         sys.excepthook = self.old_hook
 
     def clear(self):
         """ Remove the stored traceback.
         """
 
         self.args = None
 
     def add_to_message(self, message):
         """ Add the formatted display of the traceback to the message dictionary
         being returned from the interpreter to its listeners.
 
         Parameters
         ----------
         message : dict
         """
 
         # If there was no traceback, then don't add anything.
         if self.args is None:
             return
 
         # Go through the list of formatters and let them add their formatting.
         traceback = {}
-        for formatter in self.formatters:
-            traceback[formatter.identifier] = formatter(*self.args)
-        
+        try:
+            for formatter in self.formatters:
+                traceback[formatter.identifier] = formatter(*self.args)
+        except:
+            # This works always, including with string exceptions.
+            traceback['fallback'] = repr(self.args)
+
         message['traceback'] = traceback