0

I have nested exceptions handling in my code, when inner blocks do some stuff before re-raising the exception to upper layers. Traceback always reports the line number that started the exception handling. However, when running in UI debugger (Pydev/Eclipse) it stops on the outer exception block in some cases.

Consider the following code for example:

import sys

def f(a):
    c=5/a
    return c

def sub(d):
    print("Entered sub(%d)" % d)
    try:
        print("Entered try @sub")
        e = f(d)/(d-1)
        return e
    except:
        print("Do some staff before re-raising the exception upwards")
        raise

def main():
    try:
        print("Entered try @main")
        d = int(sys.argv[1])
        sub(d)
    except:
        print("Reached except block @main")
        raise

if __name__ == '__main__':
    main()

When running with argument = 0, the exception is caused at line#4 and the debugger stops on that line: Correct exception trapping

However, when running with argument = 1, the exception is caused at line#11 (as reported in the printed traceback) but the debugger stops at line#15.

Wrong exception trapping

Once the debugger stops at the incorrect location it is very difficult to watch internal variables and handle the error, especially when the code in the try block uses loops.

In Pydev->Manage Exceptions, I checked only the "suspend on uncaught exceptions".
There is a checkbox "Skip exceptions caught in same function" that seem related (because it seems like the debugger skipped the first exception in sub and stopped on "raise" statement which can be considered another exception in same function, although the documentation says that it should re-raise the same exception).
This checkbox is grayed out unless I first check "Suspend on caught exceptions*", but once enabling it the debugger gets stuck and does not stop anywhere...

Will appreciate your help.

-Moshe

2
  • Anyone has some insights about this?
    – Moshe
    Jan 3, 2019 at 9:32
  • Can you comment whether this is the right forum for my question?
    – Moshe
    Jan 7, 2019 at 7:42

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.