In reply to @llakala:matrix.org
is there any reason to prefer isNull over x == null?

Wasn't isNull soft-deprecated at one point, and the deprecation was removed because valid use cases were identified? Maybe I'm misremembering.

Generally speaking, == null and != null is simpler and more readable, and avoids invoking a function.

Same for ? vs hasAttr imo, although I don't think that one was ever deprecated.

nix-repl> options.services.pixelfed.nginx.type.description
"null or (submodule)"

nix-repl> options.services.pixelfed.nginx.valueMeta
{ }

Looks like an oversight in types.nullOr, not propagating its elem-type's valueMeta.
In fact, nullOr doesn't seem to implement v2 check+merge at all (nullOr's merge fn).

BTW, this room is really meant for discussing the nix language itself. For the module system there is https://matrix.to/#/#modules:nixos.org