PostgreSQL UPSERT Trigger returning id - function

Question

I've an UPSERT trigger on a table that may update instead of inserting while doing insert operation. I've function doing insert on that table and returning id However it doesn't return an id when it updates instead of inserting. I want to get the id in both cases.
Trigger Code
perform 1 from tera_subject
where id = new.subject_id and owner = new.user_id;
if found then
return null;
else
select id into vote_id from tera_votes where
user_id = new.user_id and
subject_id = new.subject_id;
if not found then
return new;
else
-- raise notice 'vote_id: % ; vote: %',vote_id,new.vote;
if(tg_op = 'INSERT') then
begin
-- raise notice 'redirecting to update';
update tera_votes
set vote=new.vote
WHERE id = vote_id;
end;
elsif(tg_op = 'UPDATE') then
-- raise notice 'in update';
return new;
end if;
-- raise notice 'end of trigger %',tg_op;
return null;
end if;
end if;
end;

Answer 1

I don't think you'll manage to have anything “returned” by the trigger.
What you're doing inside is:
running update based on your conditions;
suppressing the INSERT statement that fired the trigger.
This means, that INSERT is terminated in an easy way (without exception), but it also means that it's impossible to provide you any details, as trigger functions do not return any values.
If you need to have the ID of the UPSERT-ed item, consider using a function that will always return you the ID, like this one.