[PATCH v2] elf: Fix tst-relro-symbols.py argument passing

[Florian Weimer]

* Adhemerval Zanella Netto:

>>> +                        help='required symbol names')
>>>      return parser
>>>  
>>>  def main(argv):
>> 
>> Despite the use of [] here, there does not seem to be a sharing hazard:
>> 
>> import argparse
>> parser = argparse.ArgumentParser()
>> parser.add_argument('--foo', action='append', default=[])
>> print(parser.parse_args('--foo 1 --foo 2'.split()))
>> print(parser.parse_args('--foo 3 --foo 4'.split()))
>> 
>> Prints:
>> 
>> Namespace(foo=['1', '2'])
>> Namespace(foo=['3', '4'])
>> 
>> I would have expected:
>> 
>> Namespace(foo=['1', '2'])
>> Namespace(foo=['1', '2', '3', '4'])
>
> For state tracking you need to pass a namespace, as described by
> documentation [1].
>
> import argparse
>
> class State:
>    pass
>
> state = State()
> parser = argparse.ArgumentParser()
> parser.add_argument('--foo', action='append', default=[])
> parser.parse_args('--foo 1 --foo 2'.split(), namespace=state)
> print(state.foo)
> parser.parse_args('--foo 3 --foo 4'.split(), namespace=state)
> print(state.foo)
>
> It prints:
>
> ['1', '2']
> ['1', '2', '3', '4']

Oh, I was concerned that the [] would be used directly, and not cloned.
Then you'd get sharing, too.  After all, the [] is only evaluated once,
when add_argument is called.  I don't see the cloning described in the
manual.

Thanks,
Florian