Mapper order issue

I have mapper order issue:

If one of Mapper in order is higher and it extends (copyFrom) from one of lower it will throw exception that no registered mapper here. I think this is very urgent error.

Start by reproducing the mapper-order case described in the issue, where a higher mapper uses copyFrom from a lower mapper, then trace mapper registration and lookup. Done means the ordered mapper can resolve its lower dependency without the “no registered mapper” exception; no file or test location is provided.

Written by the indexing model from the issue text.