Make special backup when switching XML versions

Since the last few dozen commits change the format in irreversible ways
and could therefore be destructive and lose data for testers of the
development version, let's try to be extra careful and create "special"
backup files that aren't overwritten by subsequent backups. At least this
way people can go back to the previous state.

Of course people using the git backend don't have to worry about this as
they always can go back to any earlier save.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/save-xml.c b/save-xml.c
index dad57dc9b..5a0c6976c 100644
--- a/save-xml.c
+++ b/save-xml.c
@@ -591,7 +591,15 @@ static void try_to_backup(const char *filename)
 	while (extension[i][0] != '\0') {
 		int elen = strlen(extension[i]);
 		if (strcasecmp(filename + flen - elen, extension[i]) == 0) {
-			save_backup(filename, extension[i], "bak");
+			if (last_xml_version < VERSION) {
+				int se_len = strlen(extension[i]) + 5;
+				char *special_ext = malloc(se_len);
+				snprintf(special_ext, se_len, "%s.v%d", extension[i], last_xml_version);
+				save_backup(filename, extension[i], special_ext);
+				free(special_ext);
+			} else {
+				save_backup(filename, extension[i], "bak");
+			}
 			break;
 		}
 		i++;