TRY300: Recommend putting code after the try/except instead of inside a else

[cbornet]

When an exception handler re-raises or returns, it seems to me that it's better to put the "else" code as a follow-up to the try/except than in a "else".

Eg for the code

import logging


def reciprocal(n):
    try:
        rec = 1 / n
        print(f"reciprocal of {n} is {rec}")
        return rec
    except ZeroDivisionError:
        logging.exception("Exception occurred")
        raise

you get TRY300 Consider moving this statement to an else block
but the best for me would be to write:

import logging


def reciprocal(n):
    try:
        rec = 1 / n
    except ZeroDivisionError:
        logging.exception("Exception occurred")
        raise
    print(f"reciprocal of {n} is {rec}")
    return rec

BTW, the current example also seems incorrect as reciprocal returns an implicit None (See RET503 even though it doesn't detect it)

[MichaReiser]

I think that makes sense. But we have to be careful only to do so if all except branches re-raise and there's no existing else branch.

Moving the code after the try would change the semantic in this case.

def reciprocal(n):
    try:
        rec = 1 / n
        print(f"reciprocal of {n} is {rec}")
        return rec
    except ZeroDivisionError:
        logging.exception("Exception occurred")
        raise

    except Other:
        logging.exception("Exception occurred")