Re: [PATCH v2] sha1_name: fix uninitialized memory errors

> -- >8 --
> From: Derrick Stolee <dstolee@microsoft.com>
> Date: Tue, 27 Feb 2018 06:47:04 -0500
> Subject: [PATCH] sha1_name: fix uninitialized memory errors
> 
> During abbreviation checks, we navigate to the position within a
> pack-index that an OID would be inserted and check surrounding OIDs
> for the maximum matching prefix. This position may be beyond the
> last position, because the given OID is lexicographically larger
> than every OID in the pack. Then nth_packed_object_oid() does not
> initialize "oid".
> 
> Use the return value of nth_packed_object_oid() to prevent these
> errors.
> 
> Also the comment about checking near-by objects miscounts the
> neighbours.  If we have a hit at "first", we check "first-1" and
> "first+1" to make sure we have sufficiently long abbreviation not to
> match either.  If we do not have a hit, "first" is the smallest
> among the objects that are larger than what we want to name, so we
> check that and "first-1" to make sure we have sufficiently long
> abbreviation not to match either.  In either case, we only check up
> to two near-by objects.