Re: [PATCH v6 01/19] qapi: Replace List[str] with Sequence[str] for ifcond

[Markus Armbruster]

John Snow <jsnow@redhat.com> writes:

> On 2/16/21 3:43 AM, Markus Armbruster wrote:
>> John Snow <jsnow@redhat.com> writes:
>> 
>>> It does happen to be a list (as of now), but we can describe it in more
>>> general terms with no loss in accuracy to allow tuples and other
>>> constructs.
>>>
>>> In the future, we can write "ifcond: Sequence[str] = ()" as a default
>>> parameter, which we could not do with a Mutable type like a List.
>> Well, we could write "= []", but we shouldn't.  Worth a commit
>> message
>> tweak?
>> 
>
> It would be funny to leave it in to see if anyone tries to disprove
> me, and in the act of disproving me, learns for themselves why you
> "can't" do that. Rite of passage for Python programming.
>
> Jokes aside:
>
> "which we could not do ^safely^ with a Mutable type like a List."

Works for me.

> If that warrants further exposition by Professor Snow:
>
> "(Unsafe due to how Python initializes defaults, see
> https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments)"

I can add that if you prefer.

> I leave it to your discretion.
>
>>> Signed-off-by: John Snow <jsnow@redhat.com>
>> Reviewed-by: Markus Armbruster <armbru@redhat.com>
>> 
>
> These are worth more than BTC!

;)