Re: psql - add SHOW_ALL_RESULTS option

Hi,

On 2022-01-08 19:32:36 +0100, Fabien COELHO wrote:
> Attached v13 where the crash test is moved to tap.

The reason this test constantly fails on cfbot windows is a use-after-free
bug.

I figured that out in the context of another thread, so the debugging is
there:

https://postgr.es/m/20220113054123.ib4khtafgq34lv4z%40alap3.anarazel.de
> Ah, I see the bug. It's a use-after-free introduced in the patch:
>
> SendQueryAndProcessResults(const char *query, double *pelapsed_msec,
> bool is_watch, const printQueryOpt *opt, FILE *printQueryFout, bool *tx_ended)
>
>
> ...
> /* first result */
> result = PQgetResult(pset.db);
>
>
> while (result != NULL)
>
>
> ...
> if (!AcceptResult(result, false))
> {
> ...
> ClearOrSaveResult(result);
> success = false;
>
>
> /* and switch to next result */
> result_status = PQresultStatus(result);
> if (result_status == PGRES_COPY_BOTH ||
> result_status == PGRES_COPY_OUT ||
> result_status == PGRES_COPY_IN)
>
>
> So we called ClearOrSaveResult() with did a PQclear(), and then we go and call
> PQresultStatus().

Greetings,

Andres Freund