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

Michael Paquier <michael(at)paquier(dot)xyz> writes:
> On Wed, Feb 24, 2021 at 09:48:03PM -0500, Tom Lane wrote:
>> Anyway, I think we're better off with a test that doesn't require
>> DEBUG_LIST_MEMORY_USAGE, or preferably not even CLOBBER_FREED_MEMORY,
>> to show the problem. The test I showed misbehaves even in non-debug
>> builds, because it actually depends on what's in the innerwiths lists.

> Yeah. What I sent previously does not break in non-debug builds, but
> it does with just --enable-cassert.

> Hmm. I'd like to think that this would be enough for this thread, and
> I cannot come up now with a test able to break the lists for non-debug
> builds. But perhaps you have an idea?

For me, the example I gave fails in a non-debug build. With the code as
of HEAD, I get "ERROR: stack depth limit exceeded" or a segfault. With
your patch applied, it complains about w6 not having the correct form for
a recursive CTE.

regards, tom lane