Re: saving an exception

[Ben Cartwright]

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('\nInner ' +
traceback.format_exc().strip())

foo()
if exception:
raise exception

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

--Ben

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Re: saving an exception

[Steve Holden]

Bryan wrote:
 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?
 
You can capture the trace at the time the original exception is raised, 
if that would help? I think the traceback module lets you do that.

regards
  Steve
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Skype: holdenweb   http://holdenweb.blogspot.com
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Re: saving an exception

[Gabriel G]

At Tuesday 3/10/2006 02:15, Bryan wrote:

i would like to save an exception and reraise it at a later time.
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. Â is there anyway to fix
this?

The raise statement has 3 arguments, the third 
being the traceback (not used so much, except in cases like yours).
You can get the values using sys.exc_info()
(Don't store the traceback more than needed 
because it holds a reference to all previous stack frames...)


Gabriel Genellina
Softlab SRL 





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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

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