Fix crash with nil messages

prog2/Slot.lua

@@ -3,12 +3,12 @@
 rednet.open("back")
 
 local function interactWithCard(userUUID, mode, money)
-    if mode == "updateBalance" then
-        rednet.broadcast({
-            uuid = userUUID,
-            amount = money,
-            type = "set"
-        }, "machineBalanceModifier")
+if mode == "updateBalance" then
+    rednet.broadcast({
+        uuid = userUUID,
+        amount = money,
+        type = "set"
+    }, "machineBalanceModifier")
     end
 
     if mode == "getBalance" then
@@ -25,6 +25,11 @@ local function interactWithCard(userUUID, mode, money)
                 sleep(30)
                 --shell.run("reboot")
             end
+            if not message then
+                print("WTF!? I got a rednet message with no data!?")
+                print("Rebooting...")
+                sleep(5)
+            end
             if message.type == "account_data" and message.cardId == cardUUID then
                 local money = message.balance
                 local playerUUID = message.uuid
@@ -37,6 +42,7 @@ local function interactWithCard(userUUID, mode, money)
 end
 
 
+
 sleep(0.25)
 
 nfc = peripheral.wrap("bottom")
@@ -120,4 +126,4 @@ h.write(house)
 h.close()
 --print("If removing your card do it now")
 sleep(2)
-os.reboot()
+os.reboot()