Re: [Qemu-devel] [PATCH v3 1/7] qapi: use qemu_strtoi64() in parse_str

[Eric Blake]

On 11/8/18 7:05 AM, David Hildenbrand wrote:

> > > Thanks for the excessive answer! I think that should be enough to come
> > > up with a RFC of a *rewrite* of the string input visitor :)
> >
> > You're welcome!  I love great questions, they make me *think*.
> >
> > Besides, if something's worth doing, it's probably worth overdoing ;)
>
> I found some more ugliness, looking at the tests. I am not sure the test
> is correct here.
>
> test_visitor_in_intList():
>
> v = visitor_input_test_init(data, "1,2,0,2-4,20,5-9,1-8");
>
> -> we expect { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 20 }, implying that the
> visitor actually does sorting + duplicate elimination. Now I consider
> this is wrong. We are parsing a list of integers, not an ordered set.
>
> What's your take on this?

The test matches the current reality (yes, the string input visitor 
currently sorts and deduplicates) - but you are also right that in 
general JSON [] lists are supposed to preserve order. I suspect our use 
of -numa parsing relies on the result being sorted - but I would not be 
opposed to a rewrite that dumbs down the string visitor to provide an 
unsorted list, and move the sorting into a post-pass belonging to the 
-numa code.  Updating the tests to match as part of a rewrite is thus 
okay, if we have the justification that we audited all other users to 
see that they either don't care or that we can move the sorting out of 
the list walker and into the callers that do care.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org