Re: [Tarantool-patches] [PATCH v4 2/3] cfg: support symbolic evaluation of replication_synchro_quorum

[Cyrill Gorcunov <gorcunov@gmail.com>]

On Mon, Dec 21, 2020 at 11:02:26PM +0300, Cyrill Gorcunov wrote:
> On Mon, Dec 21, 2020 at 06:48:04PM +0100, Vladislav Shpilevoy wrote:
> > > +
> > > +	if (lua_isnumber(tarantool_L, -1))
> > > +		quorum = (int)lua_tonumber(tarantool_L, -1);
> > 
> > 1. There is a small issue:
> > 
> > tarantool> box.cfg{replication_synchro_quorum='4294967297'}
> > 2020-12-21 18:33:16.015 [47366] main/103/interactive I> set 'replication_synchro_quorum' configuration option to "4294967297"
> 
> Actually nope. When we pass this value it is treated
> as a plain number and cfg_geti trims it :(
> 
> Here is a master branch output
> 
>  | tarantool> box.cfg{replication_synchro_quorum=4294967297}
>  | ...
>  | 2020-12-21 22:59:00.614 [176552] main/103/interactive I> set 'replication_synchro_quorum' configuration option to 4294967297
> 
> Note that on master branch I have to pass real numebr not string,
> but issue is the same...
> 
> Need to think how to deal with it.

I think we might need something like below, but I'm not sure
if this won't break backward compatibility...
---
[cyrill@grain tarantool.git] git diff
diff --git a/src/cfg.c b/src/cfg.c
index 46cff1999..f896c6974 100644
--- a/src/cfg.c
+++ b/src/cfg.c
@@ -49,10 +49,18 @@ cfg_geti(const char *param)
 {
        cfg_get(param);
        int val;
-       if (lua_isboolean(tarantool_L, -1))
+       if (lua_isboolean(tarantool_L, -1)) {
                val = lua_toboolean(tarantool_L, -1);
-       else
-               val = lua_tointeger(tarantool_L, -1);
+       } else {
+               double dv = lua_tointeger(tarantool_L, -1);
+               errno = 0;
+               long long lv = llrint(dv);
+               if (errno != 0)
+                       panic("cfg_geti('%s') round failed", param);
+               if (lv > INT_MAX || lv < INT_MIN)
+                       panic("cfg_geti('%s') out of bounds", param);
+               val = (int)lv;
+       }
        lua_pop(tarantool_L, 1);
        return val;
 }
---
[cyrill@grain tarantool.git] ./src/tarantool 
Tarantool 2.7.0-112-g4c558a4ba
type 'help' for interactive help
tarantool> box.cfg{replication_synchro_quorum=4294967297}
cfg_geti('replication_synchro_quorum') out of bounds