[wingide-users] Stop on exception, within try block?

Steve Barnes gadgetsteve at hotmail.com
Tue Feb 25 15:24:08 EST 2014

On 25/02/14 00:37, Graham Wideman wrote:
> [Arrrg, resubmitted due to wrong from address.]
> Hi folks,
> Apologies if I've overlooked something obvious, but:
> Is there a setting, feature or approach to get WingIDE debugger to stop on exceptions, even within try..except blocks? (A feature I'm used to having in IDEs for other languages.)
> I find myself writing code with exception handling for later robustness, which, during initial debugging, captures programming mistakes that I'd like the IDE to stop at... necessitating rerunning the offending code and single-stepping to find and inspect the problem location.  So I'm hoping to avoid that.
> I'm thinking this would need to be enabled on a per-module (or finer-granularity) basis, since, in python, some code uses exceptions as part of expected code paths.
> Thanks!
> -- Graham
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> http://wingware.com/lists/wingide

The real solution is to use exception handling well - catch specific 
exceptions only and only put a try except block around the the line or 
group of very few lines that are likely to raise the specific 
exception.  If there is only one line between try and except then that 
is the line that had the problem.  If the error reports that you give 
are meaningful and as well as printing the exception print the 
information that you need to debug then life gets a lot easier.

Personally I would like the opposite of assert to be available - with 
assert your conditions are checked only when you are in debug mode, i.e. 
not frozen, but not otherwise.

I did manage to come up with the following idea - an assert that you can 
conditionally disable - something like the following:

In [4]: class MyError(Exception):
    ...:     pass

In [5]: DoRaise = False
In [6]: def ConditionalException(*args):
    ...:     if DoRaise:
    ...:         return (args,)
    ...:     else:
    ...:         return (MyError, )

In [7]: def test():
    ...:     try:
    ...:         1/0
    ...:     except ConditionalException(ZeroDivisionError) as e:
    ...:         print e

In [8]: test()
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-8-ea594c21b25d> in <module>()
----> 1 test()
<ipython-input-7-d7661ce74c2f> in test()
       1 def test():
       2     try:
----> 3         1/0
       4     except ConditionalException(ZeroDivisionError) as e:
       5         print e

ZeroDivisionError: integer division or modulo by zero

In [9]: DoRaise = True

In [10]: test()
integer division or modulo by zero

In [11]:

This might be useful for you and possibly others.


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