Old polls cause web exceptions and broken appearance

[gnprice]

To reproduce

• Open the web app at chat.zulip.org.
• Open the JS console.
• Visit an old message (pre-2019) with a poll, like here.

Expected

No exceptions in the console.

The poll either appears accurately, or shows a clear error message saying it can't be shown.

Actual

The poll will appear but with no options or votes:

The JS console will show a burst of exceptions:

Failed to do_process_submessages
3 poll widget: unknown inbound type: new_comment
unknown key for poll: 815,1
unknown key for poll: 815,2
unknown key for poll: 815,1
[… and more …]

From those exceptions, I'm pretty sure the poll indeed had some options in it and some votes.

Discussion

It looks like these are from before Zulip Server 2.0, where we released the polls feature:
https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-2-0-0

And in particular that new_comment name apparently was used before 2019-01, when it was renamed to new_option in c176891 .

So what's happening is that we had an experimental API, sent messages on chat.zulip.org that used it, and they're now in the history but not handled by the current code.

It's probably fine to not support the old experimental API. Probably nobody outside chat.zulip.org was using it (at least I hope not); and I don't know how much we really used it outside tests, but even where we did, it's unlikely we care too much about those polls 5+ years later.

But if we don't have support for accurately rendering the message, we should tell the user that — we shouldn't just show something misleading.

(I noticed this because zulip-mobile has the same behavior, because it's using shared code. I'll make a note on the polls issue for zulip-flutter that we should reject polls that have this old experimental API.)

[zulipbot]

Hello @zulip/server-api members, this issue was labeled with the "area: api" label, so you may want to check it out!

[Mukul1235]

Hi @gnprice
Can you please guide me how I can replicate this issue in my local? Also this seems to be like a data issue. I means ideally those polls data should be there in Django-models.

[Mukul1235]

@zulipbot claim!

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[timabbott]

@N-Shar-ma can you fix this one?

[N-Shar-ma]

@gnprice Thank you for the detailed issue report! I've started a thread at https://chat.zulip.org/#narrow/stream/101-design/topic/Old.20polls.20cause.20web.20exceptions.20and.20broken.20appearance to discuss how to deal with these old broken polls.

PS: Interestingly, new votes and options do work, they just need a reload

[timabbott]

I believe this was fixed through surgery on the chat.zulip.org database, but we should leave this open until we've decided what to do with the old tictactoe widgets generating similar exceptions.