On Fri, Oct 05, 2018 at 10:13:34PM +0200, René Scharfe wrote:
> >> -{
> >> - /*
> >> - * Note that this only looks at the ref lists the first time it's
> >> - * called. This works out in filter_refs() because even though it may
> >> - * add to "newlist" between calls, the additions will always be for
> >> - * oids that are already in the set.
> >> - */
> >
> > I don't think the subtle point this comment is making goes away. We're
> > still growing the list in the loop that calls tip_oids_contain() (and
> > which now calls just oidset_contains). That's OK for the reasons given
> > here, but I think that would need to be moved down to this code:
> >
> >> + if (strict) {
> >> + for (i = 0; i < nr_sought; i++) {
> >> + ref = sought[i];
> >> + if (!is_unmatched_ref(ref))
> >> + continue;
> >> +
> >> + add_refs_to_oidset(&tip_oids, unmatched);
> >> + add_refs_to_oidset(&tip_oids, newlist);
> >> + break;
> >> + }
> >> + }
> >
> > I.e., we need to say here why it's OK to summarize newlist in the
> > oidset, even though we're adding to it later.
>
> There is already this comment:
>
> /* Append unmatched requests to the list */
>
> And that's enough in my eyes. The refs loop at the top splits the list
> into matched ("the list") and unmatched, and the loop below said comment
> adds a few more. I see no subtlety left -- what do I miss?
It looks like tip_oids is meant as a fast lookup into what's in
unmatched and newlist. But in the second loop we continue appending to
newlist. Why is it OK that we do not update tip_oids when we do so?
I.e., something like this explains it:
diff --git a/fetch-pack.c b/fetch-pack.c
index 53914563b5..c0a1b80f4c 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -606,6 +606,12 @@ static void filter_refs(struct fetch_pack_args *args,
ref->match_status = REF_MATCHED;
*newtail = copy_ref(ref);
newtail = &(*newtail)->next;
+ /*
+ * No need to update tip_oids with ref->old_oid; we got
+ * here because either it was already there, or we are
+ * in !strict mode, in which case we do not use
+ * tip_oids at all.
+ */
} else {
ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
}
