Re: [PATCH v1 2/2] daemon: telegram: Handle MySQL error

[Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>]

On Fri, Oct 28, 2022 at 11:29 PM Ammar Faizi wrote:
> I believe there are more issues like this somewhere else. But this is
> the most hot path to get spotted. We also have to teach Rizki about this
> so he can fix it himself.

Yes.

>         if is_patch:
>                 m: "Message" = await self.client.send_patch_email(
>                         mail, tg_chat_id, text, reply_to, url
>                 )
>         else:
>                 text = "#ml\n" + text
>                 m: "Message" = await self.client.send_text_email(
>                         tg_chat_id, text,reply_to, url
>                 )
>
>         self.db.save_telegram_mail(email_id, m.chat.id, m.id)
>         for d, f in files:
>                 await m.reply_document(f"{d}/{f}", file_name=f)
>                 await asyncio.sleep(1)
>
>         utils.remove_patch(files)
>
>         return True

Even this part is also problematic, if you hit an error before
utils.remove_patch(), the patch file won't get removed because
exception will stop the current execution and throw the exception to
the previous call stack.

I hate try and catch style, because it's very easy to miss an error
like this. I prefer the way C handles error manually via return value
like:

        ret = func_call();
        if (ret < 0)
                goto clean_up;

But that's obviously not the Python style. Python prefers using
exceptions which make the caller may not be aware of this cleanup
strategy!

-- Viro