Re: [PATCH v2 4/8] fetch-pack: use ref adv. to prune "have" sent

On 06/06, Jonathan Tan wrote:

In negotiation using protocol v2, fetch-pack sometimes does not make
full use of the information obtained in the ref advertisement:
specifically, that if the server advertises a commit that the client
also has, the client never needs to inform the server that it has the
commit's parents, since it can just tell the server that it has the
advertised commit and it knows that the server can and will infer the
rest.

This is because, in do_fetch_pack_v2(), rev_list_insert_ref_oid() is
invoked before everything_local(). This means that if we have a commit
that is both our ref and their ref, it would be enqueued by
rev_list_insert_ref_oid() as SEEN, and since it is thus already SEEN,
everything_local() would not enqueue it.

Thanks for fixing this slight issue with v2.  Though maybe we need to
update the commit message here because a previous patch in this version
of the series broke up everything_local() into various parts so that it
is no longer responsible for enqueueing commits?

If everything_local() were invoked first, as it is in do_fetch_pack()
for protocol v0, then everything_local() would enqueue it with
COMMON_REF | SEEN. The addition of COMMON_REF ensures that its parents
are not sent as "have" lines.

Change the order in do_fetch_pack_v2() to be consistent with
do_fetch_pack(), and to avoid sending unnecessary "have" lines.

Signed-off-by: Jonathan Tan <redacted>
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-- 
Brandon Williams