Re: plpgsql.warn_shadow

Hi everyone,

Here's a new version of the patch. Added new tests and docs and changed
the GUCs per discussion.

plpgsql.warnings_as_errors only affects compilation at CREATE FUNCTION time:

=# set plpgsql.warnings to 'all';
SET
=#* set plpgsql.warnings_as_errors to true;
SET
=#* select foof(1); -- compiled since it's the first call in this session
WARNING: variable "f1" shadows a previously defined variable
LINE 2: declare f1 int;
^
foof
------

(1 row)

=#* create or replace function foof(f1 int) returns void as
$$
declare f1 int;
begin
end $$ language plpgsql;
ERROR: variable "f1" shadows a previously defined variable
LINE 3: declare f1 int;

Currently, plpgsql_warnings is a boolean since there's only one warning
we implement. The idea is to make it a bit field of some kind in the
future when we add more warnings. Starting that work for 9.4 seemed
like overkill, though. I tried to keep things simple.

Regards,
Marko Tiikkaja