[Issue #326] Handle empty history files correctly

Author: gsmolk

src/catalog.c

@@ -1581,6 +1581,10 @@ catalog_get_timelines(InstanceConfig *instance)
 			sscanf(file->name, "%08X.history", &tli);
 			timelines = read_timeline_history(arclog_path, tli, true);
 
+			/* History file is empty or corrupted, disregard it */
+			if (!timelines)
+				continue;
+
 			if (!tlinfo || tlinfo->tli != tli)
 			{
 				tlinfo = timelineInfoNew(tli);

src/restore.c

@@ -289,6 +289,9 @@ do_restore_or_validate(time_t target_backup_id, pgRecoveryTarget *rt,
 				/* Read timeline history files from archives */
 				timelines = read_timeline_history(arclog_path, rt->target_tli, true);
 
+				if (!timelines)
+					elog(WARNING, "Failed to get history file for target timeline %i", rt->target_tli);
+
 				if (!satisfy_timeline(timelines, current_backup))
 				{
 					if (target_backup_id != INVALID_BACKUP_ID)
@@ -1778,6 +1781,14 @@ read_timeline_history(const char *arclog_path, TimeLineID targetTLI, bool strict
 	if (last_timeline && targetTLI <= last_timeline->tli)
 		elog(ERROR, "Timeline IDs must be less than child timeline's ID.");
 
+	/* History file is empty or corrupted */
+	if (parray_num(result) != 1)
+	{
+		elog(WARNING, "History file is corrupted: \"%s\"", path);
+		pg_free(result);
+		return NULL;
+	}
+
 	/* append target timeline */
 	entry = pgut_new(TimeLineHistoryEntry);
 	entry->tli = targetTLI;