After a query cancel, the tail end of ExecQueryAndProcessResults
took care to clear any not-yet-read PGresults; but it forgot about
the one it has already read. There would only be such a result
when handling a multi-command string made with "\;", so that you'd
have to cancel an earlier command in such a string to reach the
bug at all. Even then, there would only be leakage of a single
PGresult per cancel, so it's not surprising nobody noticed this.
But a leak is a leak.
Noted while re-reviewing
90f517821, but this is independent of that:
it dates to
7844c9918. Back-patch to v15 where that came in.
if (cancel_pressed)
{
+ /* drop this next result, as well as any others not yet read */
+ ClearOrSaveResult(result);
ClearOrSaveAllResults();
break;
}