Find out what `size()` returns in scalar UDFs

[redcatbear]

Situation

In "Set" scripts it is clear what the size() method returns. But we are not sure what exactly size() produces and if that value has any relevance for the users. If it does not, it should always return 0 instead — which is a change that then belongs into the UDF client.

Acceptance Criteria

• Integration test exists that test size() in a scalar script
• Meaning of the return value documented

[redcatbear]

Actually the answer is both surprisingly simple and straight forward.

create schema sb;
--/
create or replace python3 scalar script s(x int) returns int as
def run(ctx):
   return ctx.size()
/

select s(1); --> 1
select s(null); --> 1

The size is always one for a scalar script.