Re: [RFC PATCH] During a shallow fetch, prevent sending over unneeded objects

On Fri, Aug 9, 2013 at 12:10 AM, Junio C Hamano [off-list ref] wrote:

Duy Nguyen [off-list ref] writes:

quoted

I fail to see the point here. There are two different things: what we
want to send, and what we can make deltas against. Shallow boundary
affects the former. What the recipient has affects latter. What is the
twist about?

do_rev_list() --> mark_edges_uninteresting() --> show_edge() callchain
that eventually does this:

static void show_edge(struct commit *commit)
{
        fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1));
}

was what I had in mind.

Now I see. Thanks.

mark_edges_uninteresting() actually calls
mark_edge_parents_uninteresting(), which calls show_edge(). The middle
function is important because after calculating new depth, upload-pack
calls register_shallow() for all both old and new shallow roots and
those commits will have their 'parents' pointer set to NULL, which
renders mark_edge_parents_uninteresting() no-op. So show_edge() is
never called on shallow points' parents.

quoted

As for considering objects before shallow boundary uninteresting, I
have a plan for it: kill upload-pack.c:do_rev_list(). The function is
created to make a cut at shallow boundary,...

Hmph, that function is not primarily about shallow boundary but does
all packing in general.

The edge hinting in there is for thin transfer where the sender
sends deltas against base objects that are known to be present in
the receiving repository, without sending the base objects.

OK but edge hinting is the same in pack-objects.c:get_object_list() so
the plan might still work, right? I still need to study about
extra_edge_obj in upload-pack.c though. That's something knowledge
that pack-objects won't have.
-- 
Duy