> +static void write_tree(struct object_id *result_oid,
> + struct string_list *versions,
> + unsigned int offset)
> +{
> + size_t maxlen = 0;
> + unsigned int nr = versions->nr - offset;
> + struct strbuf buf = STRBUF_INIT;
> + struct string_list relevant_entries = STRING_LIST_INIT_NODUP;
> + int i;
> +
> + /*
> + * We want to sort the last (versions->nr-offset) entries in versions.
> + * Do so by abusing the string_list API a bit: make another string_list
> + * that contains just those entries and then sort them.
> + *
> + * We won't use relevant_entries again and will let it just pop off the
> + * stack, so there won't be allocation worries or anything.
> + */
> + relevant_entries.items = versions->items + offset;
> + relevant_entries.nr = versions->nr - offset;
> + string_list_sort(&relevant_entries);
> +
> + /* Pre-allocate some space in buf */
> + for (i = 0; i < nr; i++) {
> + maxlen += strlen(versions->items[offset+i].string) + 34;
Probably should include the_hash_algo->rawsz instead of hardcoding 34.
The rest looks straightforward.
