From: Han Xin <chiyutianyi@gmail.com>
Date: Tue, 30 Nov 2021 03:23:29 GMT
Subject: Re: [PATCH v3 2/5] object-file.c: handle undetermined oid in write_loose_object()
Message-ID: <CAO0brD1U+zbqBGjOV+Vc5+AQAdrG5ULp_0=PMYeUQSxqvWQ65w@mail.gmail.com>
In-Reply-To: <2271576b-79d3-7983-d3df-5548e0a12e85@gmail.com>

On Tue, Nov 30, 2021 at 6:18 AM Derrick Stolee <stolee@gmail.com> wrote:
>
> On 11/29/2021 3:44 PM, Junio C Hamano wrote:
> > Derrick Stolee <stolee@gmail.com> writes:
> >
> >> My first reaction is to not write into .git/objects/ directly, but
> >> instead make a .git/objects/tmp/ directory and write within that
> >> directory. The idea is to prevent leaving stale files in the
> >> .git/objects/ directory if the process terminates strangely (say,
> >> a power outage or segfault).
> >
> > Even if we know the name of the object we are writing beforehand, I
> > do not think it is a good idea to open-write-close the final object
> > file.  The approach we already use everywhere is to write into a
> > tmpfile/lockfile and rename it to the final name
> >
> > object-file.c::write_loose_object() uses create_tmpfile() to prepare
> > a temporary file whose name begins with "tmp_obj_", so that "gc" can
> > recognize stale ones and remove them.
>
> The only difference is that the tmp_obj_* file would go into the
> loose object directory corresponding to the first two hex characters
> of the OID, but that no longer happens now.
>

At the beginning of this patch, I did save the temporary object in a
two hex characters directory of "null_oid", but this is also a very
strange behavior. "Gc" will indeed clean up these tmp_obj_* files, no
matter if they are in .git/objects/ or .git/objects/xx.

Thanks,
-Han Xin