6ca214fefc9e1eb707f006631d39c1e4dbafe1b5 changes handling of nil in MetaDataRef:set_string (breaking e.g. Digtron)

[j-r]

Minetest version

6ca214f

Operating system and version

Debian Oldstable (no upgrade path available)

Summary

The commit effectively replaces tolstring with checklstring.

The documentation doesn't say anything about nil. If I understand the code correctly nil is handled as an empty string which is documented to have the effect of removing an entry. So nil isn't really needed for anything, but since assigning nil is the LUA way of removing a mapping, it probably should be kept functional.

Steps to reproduce

Get a MetaDataRef in LUA and call set_string("something", nil) on it

[j-r]

Forgot to add: partially reverting only the changes to src/script/lua_api/l_metadata.cpp fixes the issue.

AFAICS there are no other instances of replacing tolstring.