Code review comment for lp:~widelands-dev/widelands/bug-1525706-artifacts

As I said before, there are no possible map loading crashes related to this branch. This code is only executed while saving a map, and then the only thing it does is write the "artifacts" tag.

I tried and failed to just iterate over the fields - seems like there is no way to safely get the size of a std::unique_ptr<array[]>.

Why is it an array and not a vector anyway?