Re: /* compiler workaround */ - what was the issue?

From: Duy Nguyen <pclouds@gmail.com>
Date: May 6, 2016, 10:17 UTC
Message-ID: <CACsJy8CBuU8H8r_f4KsnLkhLtfRv0nDo4hGS31LVn0e1Y_3OAQ@mail.gmail.com>
In-Reply-To: <xmqqtwic9o88.fsf@gitster.mtv.corp.google.com>

On Fri, May 6, 2016 at 4:41 AM, Junio C Hamano <gitster@pobox.com> wrote:

Show 15 quoted lines

> "Philip Oakley" <philipoakley@iee.org> writes:
>
>>     int saved_namelen = saved_namelen; /* compiler workaround */
>>
>> Which then becomes an MSVC compile warning C4700: uninitialized local
>> variable.
>>
>> I'm wondering what was the compiler workaround being referred to? i.e. why
>> does it need that tweak? There's no mention of the reason in the commit
>> message.
>
> That was a fairly well-known workaround for GCC that issues a false
> warning that variable is used before initialized.  I thought we
> stopped using it several years ago in new code after doing a bulk
> sanitizing

I guess that's 803a777 (cat-file: Fix an gcc -Wuninitialized warning - 2013-03-26) and more commits around that time. The split-index commit is in 2014. I must have missed the trend.

> (I think the new recommended workaround was to initialise
> such a variable to the nil value like '0' for integers).

Yep. First Jeff removed the " = xxx" part from "xxx = xxx" then Ramsay added the " = NULL" back. So we probably just do "int saved_namelen = 0;" in this case.

-- 
Duy