return -1;
/*
- * We do not bother to try a delta that we discarded
- * on an earlier try, but only when reusing delta data.
+ * We do not bother to try a delta that we discarded on an
+ * earlier try, but only when reusing delta data. Note that
+ * src_entry that is marked as the preferred_base should always
+ * be considered, as even if we produce a suboptimal delta against
+ * it, we will still save the transfer cost, as we already know
+ * the other side has it and we won't send src_entry at all.
*/
if (reuse_delta && trg_entry->in_pack &&
trg_entry->in_pack == src_entry->in_pack &&
+ !src_entry->preferred_base &&
trg_entry->in_pack_type != OBJ_REF_DELTA &&
trg_entry->in_pack_type != OBJ_OFS_DELTA)
return 0;