[Tarantool-patches] [PATCH v2] net.box: add __serialize and __tostring methods for future objects

[Yaroslav Dynnikov]

Hi! Thanks for the patch.

While reviewing it, I've noticed that the autocompletion doesn't work
for a net.box.future object. I guess it's a topic for another issue,
isn't it? Besides that, LGTM.

Best regards
Yaroslav Dynnikov

On Wed, 25 Aug 2021 at 16:35, Vladimir Davydov <vdavydov at tarantool.org>
wrote:

> On Wed, Aug 25, 2021 at 12:39:27AM +0200, Vladislav Shpilevoy wrote:
> > > diff --git a/src/box/lua/net_box.c b/src/box/lua/net_box.c
> > > index 1783da607dcc..3ed464a93437 100644
> > > --- a/src/box/lua/net_box.c
> > > +++ b/src/box/lua/net_box.c
> > > @@ -1432,6 +1432,29 @@ luaT_netbox_request_gc(struct lua_State *L)
> > >     return 0;
> > >  }
> > >
> > > +static int
> > > +luaT_netbox_request_tostring(struct lua_State *L)
> > > +{
> > > +   lua_pushstring(L, netbox_request_typename);
> > > +   return 1;
> > > +}
> > > +
> > > +static int
> > > +luaT_netbox_request_serialize(struct lua_State *L)
> > > +{
> > > +   struct netbox_request *request = luaT_check_netbox_request(L, 1);
> > > +   /*
> > > +    * If there are user-defined fields attached to the future object,
> > > +    * return them, otherwise push the type name, like __tostring does.
> > > +    */
> > > +   if (request->index_ref != LUA_NOREF) {
> > > +           lua_rawgeti(L, LUA_REGISTRYINDEX, request->index_ref);
> > > +   } else {
> > > +           lua_pushstring(L, netbox_request_typename);
> > > +   }
> > > +   return 1;
> > > +}
> >
> > 1. It does not look good that __serialize might return both a table
> > and a string depending on the object content. Perhaps it is worth to
> > return an empty table when it has no members. Otherwise, say, if I
> > store an optional value in the index and want to get it like this:
> >
> >       serialized_req.member
> >
> > then I will get sometimes nil, sometimes an error would be thrown.
> >
>
> Agree. Fixed the patch to return an empty table in case there's no user
> data stored in the future object.
>
> > > +
> > >  static int
> > >  luaT_netbox_request_index(struct lua_State *L)
> > >  {
> > > @@ -2107,6 +2130,8 @@ luaopen_net_box(struct lua_State *L)
> > >
> > >     static const struct luaL_Reg netbox_request_meta[] = {
> > >             { "__gc",           luaT_netbox_request_gc },
> > > +           {"__tostring",      luaT_netbox_request_tostring },
> > > +           {"__serialize",     luaT_netbox_request_serialize },
> >
> > 2. You have a whitespace after { in all the other lines. Could you
> > please add them here too?
>
> Sorry about that. Fixed.
>
> Incremental diff:
> --
> diff --git a/src/box/lua/net_box.c b/src/box/lua/net_box.c
> index 3ed464a93437..7a72cb324df7 100644
> --- a/src/box/lua/net_box.c
> +++ b/src/box/lua/net_box.c
> @@ -1443,14 +1443,10 @@ static int
>  luaT_netbox_request_serialize(struct lua_State *L)
>  {
>         struct netbox_request *request = luaT_check_netbox_request(L, 1);
> -       /*
> -        * If there are user-defined fields attached to the future object,
> -        * return them, otherwise push the type name, like __tostring does.
> -        */
>         if (request->index_ref != LUA_NOREF) {
>                 lua_rawgeti(L, LUA_REGISTRYINDEX, request->index_ref);
>         } else {
> -               lua_pushstring(L, netbox_request_typename);
> +               lua_newtable(L);
>         }
>         return 1;
>  }
> @@ -2130,8 +2126,8 @@ luaopen_net_box(struct lua_State *L)
>
>         static const struct luaL_Reg netbox_request_meta[] = {
>                 { "__gc",           luaT_netbox_request_gc },
> -               {"__tostring",      luaT_netbox_request_tostring },
> -               {"__serialize",     luaT_netbox_request_serialize },
> +               { "__tostring",     luaT_netbox_request_tostring },
> +               { "__serialize",    luaT_netbox_request_serialize },
>                 { "__index",        luaT_netbox_request_index },
>                 { "__newindex",     luaT_netbox_request_newindex },
>                 { "is_ready",       luaT_netbox_request_is_ready },
> diff --git a/test/box/net.box_fiber-async_gh-3107.result
> b/test/box/net.box_fiber-async_gh-3107.result
> index 450934cd6593..98c9af953efa 100644
> --- a/test/box/net.box_fiber-async_gh-3107.result
> +++ b/test/box/net.box_fiber-async_gh-3107.result
> @@ -263,7 +263,7 @@ tostring(future)
>  ...
>  future
>  ---
> -- net.box.request
> +- []
>  ...
>  future.abc = 123
>  ---
>
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