plpgsql's case bug?

Hi,

I found something strange (at least for my limited view).

in pl_exec.c:1549 in the function exec_stmt_case() we have this:

"""
/* SQL2003 mandates this error if there was no ELSE clause */
if (!stmt->have_else)
ereport(ERROR,
(errcode(ERRCODE_CASE_NOT_FOUND),
errmsg("case not found"),
errhint("CASE statement is missing ELSE part.")));
"""

resulting in this function to fail when i try to execute it

"""
postgres=# create or replace function test_case() returns boolean as $$
declare
v_one integer = 1;
v_two boolean = false;
begin
case when v_one is null then
v_two = true;
end case;
return v_two;
end
$$ language plpgsql;
CREATE FUNCTION

postgres=# select test_case();
ERROR: case not found
HINT: CASE statement is missing ELSE part.
CONTEXT: PL/pgSQL function "test_case" line 5 at CASE
"""

this is based on General Rules case 1 of chapter 13.6 (case statement)
but i don't think that behaviour is the meaning of that Rule. Even if
it is, the exception should be: "case not found for case statement"
and not just "case not found"

"""
General Rules
1) Case:
a) If the <search condition> of some <searched case statement when
clause> in a <case statement> is
True, then let SL be the <SQL statement list> of the first
(leftmost) <searched case statement when
clause> whose <search condition> is True.
b) If the <case statement> simply contains a <case statement else
clause>, then let SL be the <SQL statement
list> of that <case statement else clause>.
c) Otherwise, an exception condition is raised: case not found for
case statement, and the execution of
the <case statement> is terminated immediately.
"""

comments?

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157