Fix crash in ctf_stats on new worlds

mods/ctf_stats/init.lua

@@ -3,12 +3,19 @@ ctf_stats = {}
 local storage = minetest.get_mod_storage()
 local data_to_persist = { "matches", "players" }
 
-function ctf_stats.load()
+function ctf_stats.load_legacy()
 	local file = io.open(minetest.get_worldpath() .. "/ctf_stats.txt", "r")
-	if file then
+	if not file then
+		return false
+	end
+
 	local table = minetest.deserialize(file:read("*all"))
 	file:close()
-		if type(table) == "table" then
+	os.remove(minetest.get_worldpath() .. "/ctf_stats.txt")
+	if type(table) ~= "table" then
+		return false
+	end
+
 	ctf.log("ctf_stats", "Migrating stats...")
 	ctf_stats.matches = table.matches
 	ctf_stats.players = table.players
@@ -43,36 +50,38 @@ function ctf_stats.load()
 	}
 
 	ctf.needs_save = true
-		end
-		os.remove(minetest.get_worldpath() .. "/ctf_stats.txt")
-	else
+	return true
+end
+
+function ctf_stats.load()
+	if not ctf_stats.load_legacy() then
 		for _, key in pairs(data_to_persist) do
 			ctf_stats[key] = minetest.parse_json(storage:get_string(key))
 		end
 		ctf.needs_save = true
 	end
 
+	-- Make sure all tables are present
+	ctf_stats.players = ctf_stats.players or {}
+	ctf_stats.matches = ctf_stats.matches or {
+		wins = {
+			blue = 0,
+			red  = 0,
+		},
+		skipped = 0,
+	}
+	ctf_stats.current = ctf_stats.current or {
+		red = {},
+		blue = {}
+	}
+
+	-- Strip players which have no score
 	for name, player_stats in pairs(ctf_stats.players) do
 		if not player_stats.score or player_stats.score <= 0 then
 			ctf_stats.players[name] = nil
 			ctf.needs_save = true
 		end
 	end
-
-	ctf_stats.matches = ctf_stats.matches or {
-		wins = {
-			blue = 0,
-			red = 0,
-		},
-		skipped = 0
-	}
-
-	ctf_stats.current = ctf_stats.current or {
-		red = {},
-		blue = {}
-	}
-
-	ctf_stats.players = ctf_stats.players or {}
 end
 
 ctf.register_on_save(function()