Re: BUG #16978: Nested CTEs give ERROR in v13

On Fri, Apr 23, 2021 at 10:08:06AM -0400, Tom Lane wrote:
> PG Bug reporting form <noreply@postgresql.org> writes:
> > This narrowed down SQL (from what SQLSmith generated) seems to error out
> > only with N levels of CTE nesting - no tables / views / 1-row output. 
> > The SQL works fine with v12.4 but raises an ERROR in v13 which seems like a
> > regression. Is this owing a recent change in v13 - that could affect this?
> 
> FWIW, I don't see any error from this, either in HEAD or the
> back branches.
> 
> $ cat recursive.sql
> WITH RECURSIVE w6(c6) AS
>      (WITH w6(c6) AS
>       (WITH w8(c8) AS
>       (WITH w9(c9) AS
>       (WITH w10(c10) AS
>       (WITH w11(c11) AS
>       (WITH w_err(c12) AS
>    (SELECT 1)
>     SELECT * FROM w_err)
>     SELECT * FROM w11)
>     SELECT * FROM w10)
>     SELECT * FROM w9)
>     SELECT * FROM w8)
>      SELECT * FROM w6)
>      SELECT * FROM w6;
> $ psql -f recursive.sql
>  c6 
> ----
>   1
> (1 row)

Uh, I don't see the failure in 13 head or master, but I do see it from a
13.2 tree checkout.  I will try to find the post-13.2 commit cause.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.