Handling exceptions with Py2 and Py3

[Steven D'Aprano]

On Fri, 27 May 2016 10:24 pm, Pavlos Parissis wrote:

> Hi,
> 
> So, we have ConnectionRefusedError in Python3 but not in Python2.
> Six module doesn't provide a wrapper about this.
> 
> What is most efficient way to handle this situation in a try-catch block?

Um, could you give us a hint as to context?

What does Python 2 raise instead of ConnectionRefusedError? I don't know, so
for the sake of calling it *something* I'll say it's FooError. Then if it
is a simple name, you can do this:


if sys.version < "3":
    ConnectionRefusedError = FooError

# much later
try:
   do_the_thing()
except ConnectionRefusedError:
    ...



Or instead of checking for the version, you can check for the name:


try:
    from some_module import ConnectionRefusedError
except ImportError:
    # Must be Python 2
    from another_module import FooError as ConnectionRefusedError


If neither of these techniques help, please give more context and we can be
more specific.





-- 
Steven