Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> writes: > This function calls do_diff_cache() which eventually needs to set this > "istate" to unpack_options->src_index (*). This is an unfortunate fact > that unpack_trees() _will_ destroy src_index so we can't really pass a Wasn't the whole point of introducing src_index and dst_index to unpack-trees API so that we can keep the src_index read-only by writing the result of merge to a separate in-core dst_index? What does the above exactly mean by "will destroy src_index"? Is it now fundamental that src_index needs to lack constness, or is it something easy to fix?