FP in fix_except

[sole6]

Description

fix_except returns FP even when the code contains try..except according to Python 3 specification

Details

• OS: Win10
• Python version: 3.8
• fissix version: 20.8.0
• Can you repro on master? Yes
• Can you repro in a clean virtualenv? yes

• After looking into the issue, i think the problem is with the transform function in fix_except, where it only looks for the length of the except clause. https://github.com/jreese/fissix/blob/main/fissix/fixes/fix_except.py

if len(except_clause.children) == 4:
                (E, comma, N) = except_clause.children[1:4]
                comma.replace(Name("as", prefix=" "))
                changed = True

A fix for this can be checking if there is a command being used.

Reproduction code:

Taken from https://docs.python.org/3/tutorial/errors.html

def test():    
    try:
        raise NameError('HiThere')
    except Exception as e:
        print('An exception flew by!')