Bot is unable to tackle update ID randomization process after 1 week of bot inactivity

[milanaleksic]

Hi,

I think I have encountered a bug in the getUpdates handler. What happens is following: if my bot doesn't receive a message for a longer period of time, then it breaks on a first message by going into endless loop.

Behavior

Here is the app log (with debug turned on):

# this is happily repeated over and over and over
2018/03/20 14:33:34 getUpdates req : map[offset:[727334708] timeout:[60]]
2018/03/20 14:33:34 getUpdates resp: []
2018/03/20 14:34:25 getUpdates resp: {"ok":true,"result":[]}
...
# BUT!
2018/03/20 14:37:18 getUpdates req : map[timeout:[60] offset:[727334708]]
2018/03/20 14:37:18 getUpdates resp: [{UpdateID:117314199 Message:0x10a89540 EditedMessage:<nil> ChannelPost:<nil> EditedChannelPost:<nil> InlineQuery:<nil> ChosenInlineResult:<nil> CallbackQuery:<nil> ShippingQuery:<nil> PreCheckoutQuery:<nil>}]
2018/03/20 14:37:18 getUpdates resp: {"ok":true,"result":[{"update_id":117314199,
"message":{"message_id":64,"from":{"id":protected,"is_bot":false,"first_name":"protected","last_name":"protected","username":"protected","language_code":"en-BE"},"chat":{"id":protected,"first_name":"protected","last_name":"protected","username":"protected","type":"private"},"date":1521553038,"text":"protected"}}]}

Only after the restart is this message processed and new messages can come in.

Cause

Based on this text from page https://core.telegram.org/bots/api I believe this is the cause (it's beside the update_id)

The update‘s unique identifier. Update identifiers start from a certain positive number and increase sequentially. This ID becomes especially handy if you’re using Webhooks, since it allows you to ignore repeated updates or to restore the correct update sequence, should they get out of order. If there are no new updates for at least a week, then identifier of the next update will be chosen randomly instead of sequentially.

So, as you can see the id of the update is not any more higher than the offset, but lower, thus a problem arises since the message is not sent at all to the update message handler

I think there are 2 bugs here in fact:

1. endless loop could be avoided
2. the offset value can be ignored and smaller value can come in

[Syfaro]

I don't know if it needs the ID check in the updates loop, has anyone ever seen their bot get the same update twice?

If that's not an issue, removing that should fix it.

[variar]

I've been trying to track down this issue for several months now. Reimplemented GetUpdatesChan in my own code without id check, everything seems to be working fine.

I've checked several other bot frameworks (https://github.com/tucnak/telebot/, https://github.com/olebedev/go-tgbot) and it looks like there is no id checking there.

[ilyaglow]

Any updates here? Is id check gonna be removed in master branch? It really bites.

[Syfaro]

Closed by 5f38203

[lukaszraczylo]

Skipping updates became way too annoying. If anyone have an idea how we can tackle the issue it'd be greatly appreciated.

[teror4uks]

what's a problem use != in if statement instead > ? I mean use in getUpdateChan func

if update.UpdateID != config.Offset {
    config.Offset = update.UpdateID
    ch <- update
}