Re: [PATCH v14 03/11] tests: Add test for QAPI builtin type time

[Tao Xu <tao3.xu@intel.com>]

On 11/7/2019 9:31 PM, Eduardo Habkost wrote:
> On Thu, Nov 07, 2019 at 02:24:52PM +0800, Tao Xu wrote:
>> On 11/7/2019 4:53 AM, Eduardo Habkost wrote:
>>> On Mon, Oct 28, 2019 at 03:52:12PM +0800, Tao Xu wrote:
>>>> Add tests for time input such as zero, around limit of precision,
>>>> signed upper limit, actual upper limit, beyond limits, time suffixes,
>>>> and etc.
>>>>
>>>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>>>> ---
>>> [...]
>>>> +    /* Close to signed upper limit 0x7ffffffffffffc00 (53 msbs set) */
>>>> +    qdict = keyval_parse("time1=9223372036854774784," /* 7ffffffffffffc00 */
>>>> +                         "time2=9223372036854775295", /* 7ffffffffffffdff */
>>>> +                         NULL, &error_abort);
>>>> +    v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
>>>> +    qobject_unref(qdict);
>>>> +    visit_start_struct(v, NULL, NULL, 0, &error_abort);
>>>> +    visit_type_time(v, "time1", &time, &error_abort);
>>>> +    g_assert_cmphex(time, ==, 0x7ffffffffffffc00);
>>>> +    visit_type_time(v, "time2", &time, &error_abort);
>>>> +    g_assert_cmphex(time, ==, 0x7ffffffffffffc00);
>>>
>>> I'm confused by this test case and the one below[1].  Are these
>>> known bugs?  Shouldn't we document them as known bugs?
>>
>> Because do_strtosz() or do_strtomul() actually parse with strtod(), so the
>> precision is 53 bits, so in these cases, 7ffffffffffffdff and
>> fffffffffffffbff are rounded.
> 
> My questions remain: why isn't this being treated like a bug?
> 
Hi Markus,

I am confused about the code here too. Because in do_strtosz(), the 
upper limit is

val * mul >= 0xfffffffffffffc00

So some data near 53 bit may be rounded. Is there a bug?