In PQsendQueryStart(), avoid leaking any left-over async result.

tglsfdc · tglsfdc · commit fb6825fe5765 · 2016-10-10T10:35:58.000-04:00
Ordinarily there would not be an async result sitting around at this
point, but it appears that in corner cases there can be.  Considering
all the work we're about to launch, it's hardly going to cost anything
noticeable to check.

It's been like this forever, so back-patch to all supported branches.

Report: &lt;CAD-Qf1eLUtBOTPXyFQGW-4eEsop31tVVdZPu4kL9pbQ6tJPO8g@mail.gmail.com&gt;
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
@@ -1240,8 +1240,7 @@ PQsendQueryStart(PGconn *conn)
 	}
 
 	/* initialize async result-accumulation state */
-	conn->result = NULL;
-	conn->curTuple = NULL;
+	pqClearAsyncResult(conn);
 
 	/* ready to send command message */
 	return true;

Original file line number	Diff line number	Diff line change
`@@ -1240,8 +1240,7 @@ PQsendQueryStart(PGconn *conn)`
`1240`	`1240`	`}`
`1241`	`1241`
`1242`	`1242`	`/* initialize async result-accumulation state */`
`1243`		`- conn->result = NULL;`
`1244`		`- conn->curTuple = NULL;`
	`1243`	`+ pqClearAsyncResult(conn);`
`1245`	`1244`
`1246`	`1245`	`/* ready to send command message */`
`1247`	`1246`	`return true;`