dropping into the debugger on an exception

[Jon Perez]

(sorry for the duplicate post, just wanted to make the subject
line clearer)

How do you set up pdb such that you will automatically
get dropped into its prompt if an unanticipated exception
occurs in a script you are using?

ASPN Python cookbook gives you the following method
which you can add to your script and hook into sys.excepthook.
But is there a way to do it without adding stuff to your
script?  (It's okay if this means having to invoke the script
from within pdb, but #1, I don't know how to get it stay inside
pdb in the case of an /unanticipated/ exception.  And #2, I
don't know how to pass [the equivalent of] command-line
arguments to a script invoked from within pdb.)



def info(type, value, tb):
    if hasattr(sys, 'ps1') or not sys.stderr.isatty():
       # we are in interactive mode or we don't have a tty-like
       # device, so we call the default hook
       sys.__excepthook__(type, value, tb)
    else:
       import traceback, pdb
       # we are NOT in interactive mode, print the exception...
       traceback.print_exception(type, value, tb)
       print
       # ...then start the debugger in post-mortem mode.
       pdb.pm()

sys.excepthook = info