Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:
On 10.10.25 10:52, Michael Tokarev wrote:
Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:
They were deprecated in 9.2, now we can remove them. New options to use are reconnect-ms. Speaking of the option itself.. I'd not remove it, instead, I'd de-deprecate it, and allow units to be specified for it,
On 10/9/25 17:17, Markus Armbruster wrote: like reconnect=10ms (defaults to s). Or reconnect=0.1 (in fractions of second). But it's just me, it looks like :)
QAPI is not for humans) So simple milliseconds integer is better, then parse the variety of suffixes. And it better fit into json (number is number, not a string)
Also, `has_reconnect_ms` becomes redundant after applying this patch, - it should be enough to use just reconnect_ms, which defaults to 0. But this can be done in a subsequent cleanup.
You mean just use sock->reconnect_ms instead of explicit
int64_t reconnect_ms = sock->has_reconnect_ms ? sock->reconnect_ms : 0;
?
We routinely exploit that QAPI initializes absent members to zero.
I believe that QMP will zero-initialize everything. But I'm not sure that we do zero initialize this structure on all paths.. Keeping also in mind handling other fields here like
bool is_telnet = sock->has_telnet ? sock->telnet : false; bool is_tn3270 = sock->has_tn3270 ? sock->tn3270 : false; bool is_waitconnect = sock->has_wait ? sock->wait : false; bool is_websock = sock->has_websocket ? sock->websocket : false;
To drop this, we should check for all paths, that incoming structure is zero-initialized. And no guarantee that it does not break in future.
Probably, we can implement a new QAPI feature "value with default to zero", so that we can avoid existence of .has_foo field at all for such fields. No field - no problem.. But not in this series)
The simple way to do "optional" is to have the machinery supply a default value. The less simple way is to add a distinct extra value that means "absent". This permits "absent" to means something else than any value. QAPI does the latter. Not my choice; I inherited it :) For pointers, generated C uses null as distinct extra value. Works, because "present" implies non-null. For other types, generated C uses a pair of variables (has_FOO, FOO), where (true, V) means present with value V (false, zero) means absent (false, non-zero) is invalid This results in slightly more complicated code. Most of the time, code maps "absent" to a default value. This default value is not visible in the schema, it's buried in the C code. When a type gets used in multiple places, each place can pick its own default. Bothersome to document, and the system cannot ensure the code matches its documentation. Strong dislike. Special case: when the default value is zero, we can ignore has_FOO and just use FOO. See "routinely exploit" above. We could extend the QAPI schema language to let us specify the default value. The generator could then elide has_FOO. Code would become simpler.