From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 8 Apr 2024 21:00:07 +0000 (-0400)
Subject: In psql, avoid leaking a PGresult after a query is cancelled.
X-Git-Tag: REL_16_3~45
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a85e3ba1c9482dd04bec11588a5169a3430939af;p=thirdparty%2Fpostgresql.git

In psql, avoid leaking a PGresult after a query is cancelled.

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.
---

diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index 5973df2e39e..3b0710a9e2e 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -1662,6 +1662,8 @@ ExecQueryAndProcessResults(const char *query,
 
 		if (cancel_pressed)
 		{
+			/* drop this next result, as well as any others not yet read */
+			ClearOrSaveResult(result);
 			ClearOrSaveAllResults();
 			break;
 		}