saving an exception

[Bryan]

hi,

i would like to save an exception and reraise it at a later time.


something similar to this:

exception = None
def foo():
    try:
        1/0
    except Exception, e:
        exception = e

if exception: raise exception


i have a need to do this because in my example foo is a callback from c code
which was originally called from python and i can't modify the c code.
with the above code, i'm able to successfully raise the exception, but the
line number of the exception is at the place of the explicit raise instead
of the where the exception originally occurred.  is there anyway to fix
this?


thanks,

bryan

[Ben Cartwright]

Re: saving an exception

Bryan wrote:

i would like to save an exception and reraise it at a later time.
>
something similar to this:
>
exception = None
def foo():
try:
1/0
except Exception, e:
exception = e
>
if exception: raise exception
>
with the above code, i'm able to successfully raise the exception, but the
line number of the exception is at the place of the explicit raise instead
of the where the exception originally occurred. is there anyway to fix
this?

Sure: generate the stack trace when the real exception occurs. Check
out sys.exc_info() and the traceback module.

import sys
import traceback

exception = None
def foo():
global exception
try:
1/0
except Exception:
# Build a new exception of the same type with the inner stack
trace
exctype = sys.exc_info()[0]
exception = exctype('\nInne r ' +
traceback.forma t_exc().strip() )

foo()
if exception:
raise exception

# Output:
Traceback (most recent call last):
File "foo.py", line 15, in <module>
raise exception
ZeroDivisionErr or:
Inner Traceback (most recent call last):
File "foo.py", line 8, in foo
1/0
ZeroDivisionErr or: integer division or modulo by zero

--Ben