+void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
+{
+ struct cache_entry *old = istate->cache[nr], *new;
+ int namelen = strlen(new_name);
+
+ new = xmalloc(cache_entry_size(namelen));
+ copy_cache_entry(new, old);
+ new->ce_flags &= ~(CE_STATE_MASK | CE_NAMEMASK);
+ new->ce_flags |= (namelen >= CE_NAMEMASK ? CE_NAMEMASK : namelen);
+ memcpy(new->name, new_name, namelen + 1);
+
+ cache_tree_invalidate_path(istate->cache_tree, old->name);
+ remove_index_entry_at(istate, nr);
+ add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+}
+