Re: [Tarantool-patches] [PATCH] decimal: fix build with GCC 10

[Serge Petrenko <sergepetrenko@tarantool.org>]

08.06.2020 14:22, Alexander Turenko пишет:
> The patch itself is okay.
>
> On Fri, Jun 05, 2020 at 05:01:25PM +0300, Serge Petrenko wrote:
>> GCC 10 produces the following error:
>> cc1: warning: function may return address of local variable [-Wreturn-local-addr]
>>
>> Fix it.
> It would be good to mention whether it is a real problem or
> false-positive. (The patch is already pushed, so this comment is just
> for information.)


It's a false-positive. The return value  is  only  used to test `dec != 
NULL`.

`dec == NULL` means an error.So, no UB here.

I guess no need for a changelog entry then.

>
> As I see, we actually return a data on the stack before the patch, so it
> worth to mention the bugfix in the release notes. Kirill, can you add
> this?
>
> @ChangeLog
>
> - Fix use-after-scope when converting a decimal number to int64_t or
>    uint64_t that may lead to undefined behaviour in tuple comparators and
>    so in behaviour of space indices (part of gh-4966).
>
> (Serge, correct me if I'm wrong here.
>
> BTW, are those hints pesisted for vinyl? Can we get wrong results even
> after upgrade?
>
> WBR, Alexander Turenko.

-- 
Serge Petrenko