Failure to Stop on Exceptions

Index of All Documentation » Wing Pro Reference Manual » Trouble-shooting Guide » Trouble-shooting Failure to Debug »

Failure to stop on exceptions is most commonly caused by the same factors that cause failure to stop on breakpoints, although in this case the debugger may stop but fail to show the source code.

Another factor in debugging exceptions is that they may be handled by a catch-all exception handler. Wing doesn't stop on these unless they also print the exception.

The simple work-around for this is to set a breakpoint in the exception handler.

An alternative is to recode your app by adding the following code to catch-all exception handlers:

import os, sys
if 'WINGDB_ACTIVE' in os.environ:

The above only works with When Printed exception handling mode, as set by the Debugger > Exceptions > Report Exceptions preference).

The following variant can be used with other exception handling modes:

import os

# No handler when running in Wing's debugger
if 'WINGDB_ACTIVE' in os.environ:

# Handle unexpected exceptions gracefully at other times
    # handler here

Note that environments such as wxPython, PyGTK, and others include catch-all handlers for unexpected exceptions raised in the main loop, but those handlers cause the exception traceback to be printed and thus will be reported correctly by Wing without any modification to the handler.