fixup! index-pack: avoid immediate object fetch while parsing packfile

The previous fixup (cdaf540) replaced OBJECT_INFO_FOR_PREFETCH with
HAS_OBJECT_FETCH_PROMISOR, reasoning that the former flag "never
worked." However, these are flags for two different functions:
OBJECT_INFO_FOR_PREFETCH was for odb_read_object_info_extended() (which
the old oid_object_info_extended() forwarded to), while
HAS_OBJECT_FETCH_PROMISOR is for odb_has_object().

The call site was migrated to odb_has_object() as part of the upstream
refactoring, but odb_has_object(odb, oid, HAS_OBJECT_FETCH_PROMISOR)
sets only OBJECT_INFO_QUICK without OBJECT_INFO_SKIP_FETCH_OBJECT,
which means it WILL trigger remote fetches via gvfs-helper. This
defeats the purpose of the original commit, which was to prevent
index-pack from individually fetching every object it encounters during
the collision check.

Passing 0 instead gives us both OBJECT_INFO_QUICK and
OBJECT_INFO_SKIP_FETCH_OBJECT, which is the correct equivalent of the
original OBJECT_INFO_FOR_PREFETCH behavior.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

builtin/index-pack.c

@@ -891,7 +891,7 @@ static void sha1_object(const void *data, struct object_entry *obj_entry,
 	if (startup_info->have_repository) {
 		read_lock();
 		collision_test_needed = odb_has_object(the_repository->objects, oid,
-						       HAS_OBJECT_FETCH_PROMISOR);
+						       0);
 		read_unlock();
 	}