repeated nft set add ignores changed parameters

[Florian Westphal <fw@strlen.de>]

When re-adding an existing set no error is returned
and any changed parameters are ignored.

$ nft list ruleset | tee A
table ip nat {
     map m {
	typeof meta mark : ip saddr
	flags dynamic,timeout timeout 1h
   }
  }
}
$ $EDITOR $A  # change timeout
grep timeout\   A
timeout 1m
$ nft -f A
$ nft list ruleset|grep timeout\ 
timeout 1h


Is this a bug?  Is there really no alternative than to completely
zap the entire set/map?

Similar issue:
adding set bla, followed by map bla passes without error but 'map bla'
gets ignored.

On a related note, what happened to 'netfilter: nf_tables: add support
to destroy operation':

https://patchwork.ozlabs.org/project/netfilter-devel/patch/20221028100531.58666-1-ffmancera@riseup.net/

?

Some people are (rightfully) complaining that they need to do stupid
'add','delete' (or even add/delete/add!) games.

I don't really mind if we go with new commands (Fernandos patch), if we
change behaviour to ignore -ENOENT errors (in which case does it
makes sense to return an error...?) or if we add a nlmsg flag (kinda
inverse to NLMSG_F_EXCL), but current state is not nice at all.