Re: [PATCH v2 4/4] commit: rewrite read_graft_line

Patryk Obara [off-list ref] writes:

The previous implementation of read_graft_line used calculations based
on GIT_SHA1_RAWSZ and GIT_SHA1_HEXSZ to determine the number of commit
ids in a single graft line.  New implementation does not depend on these
constants, so it adapts to any object_id buffer size.

To make this possible, FLEX_ARRAY of object_id in struct was replaced
by an oid_array.

There is a leap in logic between the two paragraphs.  Your use of
parse_oid_hex() is good.  But I do not think moving the array body
to outside commit_graft structure and forcing it to be separately
allocated is necessary or beneficial.  When we got a single line, we
know how many fake parents a child described by that graft line has,
and you can still use of FLEX_ARRAY to avoid separate allocation
and need for separate freeing of it.