[Proposal] Allow disabling "try-except" clauses evaluation.

[CaBazaga]

When using third party services libraries, or even on your own code, you may find a scenario were a function may return several different types of exceptions each of them requiring a simple but different action to be taken.

Exhaustive Exception treatment on those cases leads to a high complexity result which is right, as per the complexity calculation strategy, but an undesired result.

def foo(bar):
    try:
        do_whatever(bar)
    except TypeA:
        do_something_related_to_TypeA()
    except TypeB:
        do_something_related_to_TypeB()
    except TypeC:
        do_something_related_to_TypeC()
    except TypeD:
        do_something_related_to_TypeD()
    except TypeE:
        do_something_related_to_TypeE()
    except TypeF:
        do_something_related_to_TypeF()
    except TypeG:
        do_something_related_to_TypeG()
    except TypeH:
        do_something_related_to_TypeH()
    except TypeI:
        do_something_related_to_TypeI()
    except TypeJ:
        do_something_related_to_TypeJ()

python -Bm mccabe deffoobar.py                     
1:0: 'foo' 12

It will be interesting being able to ignore exceptions branching to properly compute the complexity of the actual function logic without the burden of the exception treatment one.

[sigmavirus24]

I don't think allowing folks to choose what contributes to complexity globally is really something we want to introduce. We wouldn't be even considering this on a "per-block" basis so it would be a global option and I think that's going to actively thwart the reason people bother using McCabe