Re: [Tarantool-patches] [PATCH 1/4] box: add a single execution guard to clear_synchro_queue

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

>> But I don't mind having this guard here if you want it. Only my thoughts.
>>> if (try_wait) { /* Wait until pending confirmations/rollbacks reach us. */ diff --git a/src/box/lua/ctl.c b/src/box/lua/ctl.c index bf26465e6..a3447f3e7 100644 --- a/src/box/lua/ctl.c +++ b/src/box/lua/ctl.c @@ -81,8 +81,8 @@ lbox_ctl_on_schema_init(struct lua_State *L) static int lbox_ctl_clear_synchro_queue(struct lua_State *L) { - (void) L; - box_clear_synchro_queue(true); + if (box_clear_synchro_queue(true) != 0) + return luaT_error(L); 
>> Maybe better use nil + error object return way? I thought we still use it in the new code.
> 
> Hm, I haven't seen us do that in lua/C.
> As far as I know, every box.* method throws a lua error in case of failure.
> I may miss something. Is there a reason for returning nil + error instead of
> throwing?
The only reason is that it is our new rule for writing Lua code.
http://www.tarantool.io/en/doc/latest/dev_guide/lua_style_guide/#error-handling

Not every box function, really.

As some examples I can remember box.session.push(),
box.unprepare, box.execute, box.prepare.

There are also examples for non-box Lua methods. You
can grep by luaT_push_nil_and_error() to find almost all
usages in Lua C API. To find usages in .lua files you
can try to look for `return nil, err*`, but it won't
show everything.

For me nil,err looks better, but I understand that there
is a lot of old code still using exceptions. And maybe we
would better stick to them. I suggest to ask in the chat
if in doubt.