From: Duy Nguyen <pclouds@gmail.com>
Date: Thu, 30 May 2013 13:08:01 GMT
Subject: Re: [PATCH 1/4] commit: reload cache properly
Message-ID: <CACsJy8BuSaY=H9Pb6FuTEiQkm18h-kW86ZOVtaaDpMkjFEnqcQ@mail.gmail.com>
In-Reply-To: <87ehcok6gl.fsf@linux-k42r.v.cablecom.net>

On Thu, May 30, 2013 at 7:17 PM, Thomas Rast <trast@inf.ethz.ch> wrote:
> Felipe Contreras <felipe.contreras@gmail.com> writes:
>
>> We are supposedly adding files, to to which cache if 'the_index' is
>> discarded?
> [...]
>>       if (!current_head) {
>>               discard_cache();
>> +             if (read_cache() < 0)
>> +                     die(_("cannot read the index"));
>>               return;
>>       }
>
> It is not obvious to me that this is a correct change.  discard_cache()
> without subsequent reloading could also legitimately be used to empty
> the index.  So if you are fixing a bug, please justify the change and
> provide a testcase to guard against it in the future.

That discard_cache line I think came from fa9dcf8 (Fix performance
regression for partial commits - 2008-01-13). The code flow back then
was

if (initial_commit)
   discard_cache();

add_remove_files();
/* do something more */

A quick look from current code seems to indicate this pattern is still
valid for creating partial commits, where temporary index will be
thrown away afterwards. But I may be wrong.
--
Duy