Cleanup ClusterInfo initialization in pg_upgrade

contrib/pg_upgrade/info.c

@@ -22,6 +22,12 @@ static void free_rel_infos(RelInfoArr *rel_arr);
 static void print_db_infos(DbInfoArr *dbinfo);
 static void print_rel_infos(RelInfoArr *arr);
 
+void
+initialize_cluster_info(ClusterInfo *cluster)
+{
+	cluster->dbarr.ndbs = 0;
+	cluster->dbarr.dbs = NULL;
+}
 
 /*
  * gen_db_file_maps()

contrib/pg_upgrade/pg_upgrade.c

@@ -63,9 +63,10 @@ main(int argc, char **argv)
 	char	   *deletion_script_file_name = NULL;
 	bool		live_check = false;
 
+	initialize_cluster_info(&old_cluster);
+	initialize_cluster_info(&new_cluster);
+
 	parseCommandLine(argc, argv);
-	old_cluster.dbarr.ndbs = 0;
-	new_cluster.dbarr.ndbs = 0;
 
 	output_check_banner(&live_check);
 

contrib/pg_upgrade/pg_upgrade.h

@@ -326,6 +326,7 @@ void		check_loadable_libraries(void);
 
 /* info.c */
 
+void		initialize_cluster_info(ClusterInfo *cluster);
 FileNameMap *gen_db_file_maps(DbInfo *old_db,
 				 DbInfo *new_db, int *nmaps, const char *old_pgdata,
 				 const char *new_pgdata);