Re: [Qemu-devel] [PATCH v2 1/3] libqtest: Ignore QMP events when parsing the response for HMP commands

[Thomas Huth]

On 03.04.2017 21:09, John Snow wrote:
> 
> 
> On 03/30/2017 03:50 AM, Thomas Huth wrote:
>> When running certain HMP commands (like "device_del") via QMP, we
>> can sometimes get a QMP event in the response first, so that the
>> "g_assert(ret)" statement in qtest_hmp() triggers and the test
>> fails. Fix this by ignoring such QMP events while looking for the
>> real return value from QMP.
>>
>> Signed-off-by: Thomas Huth <address@hidden>
>> ---
>>  tests/libqtest.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/tests/libqtest.c b/tests/libqtest.c
>> index a5c3d2b..c9b2d76 100644
>> --- a/tests/libqtest.c
>> +++ b/tests/libqtest.c
>> @@ -580,6 +580,12 @@ char *qtest_hmpv(QTestState *s, const char *fmt, 
>> va_list ap)
>>                       " 'arguments': {'command-line': %s}}",
>>                       cmd);
>>      ret = g_strdup(qdict_get_try_str(resp, "return"));
>> +    while (ret == NULL && qdict_get_try_str(resp, "event")) {
>> +        /* Ignore asynchronous QMP events */
>> +        QDECREF(resp);
>> +        resp = qtest_qmp_receive(s);
>> +        ret = g_strdup(qdict_get_try_str(resp, "return"));
>> +    }
>>      g_assert(ret);
>>      QDECREF(resp);
>>      g_free(cmd);
>>
> 
> You've probably been asked this, but can you just shove the QMP response
> you don't want into the event queue for consumption by other calls?

Well, this is the qtest_hmpv() function, so I assume that the caller
just wants to execute a HMP command and does not really care about QMP
events. If you care about QMP events, you should use the qmp functions
instead.

 Thomas