Weird scroll-animation/jumps in Chat

[r10s]

sometimes, there is some unneeded scrolling of the message list:

instead of just shifting the view some pixels up in case of a new message,
scrolling takes place from the very top to the bottom.

this issue is pretty old, but here is a way to get a reproducible comparison with correct scrolling:

• open a filled the "Saved Messages" chat
• send a first short message "s1" -> scrolling is fine, just a few pixels up
• send a second short message "s2" -> scrolling from very top to the bottom, same for subsequent messages from the same device

leave the "Saved Messages" chat open, but now send a message from another device:

• messages "o1", "o2" -> scrolling is fine, just a few pixels up
• from same device, "s3", again -> scrolling from very top to the bottom

so, question is, what is the difference between wrong s2, s3 and fine s1, o1, o2

RPReplay_Final1720705004.mov

(ignore the flickering scroll down button, see here)

---

Note to self:

let messageId = ui["message_id"] as? Int ?? 0
if messageId > 0 {
    let msg = self.dcContext.getMessage(id: messageId)

[feld]

This looks like it was supposed to be fixed in 1.46.8 but it is very much persisting. It still has jumpy-ness and it's very annoying how it will never scroll to bottom automatically like when you're sending multiple consecutive messages in a chat

[Amzd]

This is caused by the textView being removed from superview and re-added when ChatViewController.configureDraftArea is called, and can be fixed by adding guard view !== middleContentView else { return } in InputBarAccessoryView.setMiddleContentView. I will fix this in a PR probably this weekend.

I am rewriting the ChatViewController to have its tableView flipped which means we need to do way less scrolling tricks because scroll views by default scroll up when a cell is added, so when flipped it will scroll down when a cell is added.

[r10s]

I will fix this in a PR probably this weekend.

that'd be very welcome - we're struggling with that quite a while without really getting a grip on it. really looking forward and curious about the details 🤩

[r10s]

very nice to have this fixed! 👌
this is a very old bug (much oder than this issue :)