Re: BUG #16801: Invalid memory access on WITH RECURSIVE with nested WITHs

On Thu, Feb 25, 2021 at 10:30:41AM +0900, Michael Paquier wrote:
> Your patch does not have a test for that, but it fixes the list
> handling. With more nested levels and some UNIONs, the patch I sent
> previously would equally break, though I am not sure we need more than
> what I am sending here. What do you think about this extra test?

By the way, here is a fancier test case to make the list handling
recurse much more in checkWellFormedRecursionWalker():
WITH RECURSIVE outermost(x) AS (
SELECT 1
UNION (WITH innermost1 AS (
SELECT 2
UNION (WITH innermost2 AS (
SELECT 3
UNION (WITH innermost3 AS (
SELECT 4
UNION (WITH innermost4 AS (
SELECT 5
UNION (WITH innermost5 AS (SELECT 6)
SELECT * FROM innermost5))
SELECT * FROM innermost4))
SELECT * FROM innermost3))
SELECT * FROM innermost2))
SELECT * FROM outermost
UNION SELECT * FROM innermost1)
)
SELECT * FROM outermost ORDER BY 1;
--
Michael