Re: [PATCH v2 1/3] index-pack: add --unpack-limit to unpack objects

From: Duy Nguyen <pclouds@gmail.com>
Date: Sep 8, 2013, 06:28 UTC
Message-ID: <CACsJy8DeJnwJ2hxbKs+ks3Rp6h+uedFA+qt8JTTwyen8sF7XMw@mail.gmail.com>
In-Reply-To: <20130908044417.GD14019@sigill.intra.peff.net>

On Sun, Sep 8, 2013 at 11:44 AM, Jeff King <peff@peff.net> wrote:

Show 16 quoted lines

> On Fri, Sep 06, 2013 at 07:46:01AM +0700, Nguyen Thai Ngoc Duy wrote:
>
>> ---
>>  I had something that could unpack without writing to temp pack file
>>  but I scraped it and chose this way because it follows closely how
>>  index-pack works. It's a good thing imo because .pack v4 is coming
>>  and I don't know how v4 may impact this unpack code path. Once things
>>  are settled, we can revisit and open a separate code path if it's
>>  still a good idea.
>
> From a cursory read, this seems fine. If it were done in complete
> isolation, I'd say it was a slight regression, just because we are doing
> more I/O for the unpack case, and it is not really saving us any code
> (it is not like we can throw away unpack-objects, as I think we would
> want to keep it as a last resort for getting data out of malformed or
> otherwise non-indexable packs).

I can see unpack-objects is more tolerable on corrupt/incomplete packs. If index-pack finds something wrong, it aborts the whole process. I think we can make index-pack stop at the first bad object, adjust nr_objects, and try to recover as much as possible out of the good part. Any other reasons to keep unpack-objects (because I still want to kill it)?

Show 5 quoted lines

> But I can also see it making pack v4 handling easier. So it would make
> sense to me to put it at the start of a series adding pack v4 indexing.
> By the end of the series you would be able to see the benefits of the
> reduced code complexity. Until then, it is a "probably this will help
> later" change.

Agreed.

-- 
Duy