Re: [PATCH v7 10/13] pack-objects: clarify the use of object_entry::size

From: Jeff King <peff@peff.net>
Date: Mar 30, 2018, 21:04 UTC
Message-ID: <20180330210416.GH14782@sigill.intra.peff.net>
In-Reply-To: <20180324063353.24722-11-pclouds@gmail.com>

On Sat, Mar 24, 2018 at 07:33:50AM +0100, Nguyễn Thái Ngọc Duy wrote:

Show 11 quoted lines

> While this field most of the time contains the canonical object size,
> there is one case it does not: when we have found that the base object
> of the delta in question is also to be packed, we will very happily
> reuse the delta by copying it over instead of regenerating the new
> delta.
> 
> "size" in this case will record the delta size, not canonical object
> size. Later on in write_reuse_object(), we reconstruct the delta
> header and "size" is used for this purpose. When this happens, the
> "type" field contains a delta type instead of a canonical type.
> Highlight this in the code since it could be tricky to see.

Thanks for digging down here. I have definitely been confused by this in the past.

The subject says "clarify" so I was a little surprised to see code changes. It looks like we're just avoiding reassigning on top of the value repeatedly, which is part of that clarification. It looks like a noop to me.

-Peff