python exception not raised if finally returns value

Question

Can anyone explain why the following example does not raise the Exception?

def foo():
    try:
        0/0
    except Exception:
        print('in except')
        raise
    finally:
        print('in finally')
        return 'bar'

my_var = foo()
print(my_var)

This just returns:

in except
in finally
bar

Where as the same code without the return 'bar' statement throws the exception:

in except
in finally
Traceback (most recent call last):
  File "test.py", line 10, in <module>
    my_var = foo()
  File "test.py", line 3, in foo
    0/0
ZeroDivisionError: division by zero

you can catch the exception, assign it to a previously defined None variable and then reraise it in finally: Bit trickier to get working in python 3 than 2, i’ll post it later. useful to close resources but still throw the exception — JL Peyret, Nov 22 '18 at 21:27

score 2 · Accepted Answer · answered Nov 22 '18 at 16:38

2

see https://stackoverflow.com/a/19805813/1358308 for more detail, but in brief

the finally block should always be executed, Python therefore has to ignore the raise statement as that would violate semantics

answered Nov 22 '18 at 16:38

Sam Mason

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python exception not raised if finally returns value

1 Answers1