Fix GH-21575: Memory leak with notices in pgsql persistent connections.

Author: devnexen

ext/pgsql/pgsql.c

@@ -187,6 +187,12 @@ static void pgsql_link_free(pgsql_link_handle *link)
 
 	zend_hash_del(&PGG(connections), link->hash);
 
+	if (link->persistent) {
+		/* Reset the notice processor context to NULL so that notices emitted
+		 * during a subsequent PQreset on this persistent PGconn are safely
+		 * ignored rather than written to a stale link handle. */
+		PQsetNoticeProcessor(link->conn, _php_pgsql_notice_handler, NULL);
+	}
 	link->conn = NULL;
 	zend_string_release(link->hash);