DC-Desktop displays messages in incorrect order

[Raiden-GH]

DC-Desktop displays messages in incorrect order

[link2xt]

Most recent change I see is: deltachat/deltachat-core-rust#4623

Messages are sorted according to time sent, but never above the last read message. If you read every message immediately after receiving, messages will be sorted in the order they are received. If you receive all messages at once and then read them, they all will be ordered in the order of sent timestamps.

[Simon-Laux]

It seems to be based on the time received and not the time sent.

this is intended behaviour, also if this would be an issue, then it would be a core issue.

the forum has multiple discussions about it:

• https://support.delta.chat/t/order-of-messages/698
• https://support.delta.chat/t/deltachat-almost-unusable-for-me-due-to-out-of-order-message-delivery/2241
• https://support.delta.chat/t/bug-feature-request-making-sure-the-message-are-displied-in-the-correct-order-even-if-some-take-longer-to-arrive/1843

[link2xt]

Unless there is a clear scenario which we can detect and improve with a test, I would rather not change anything.

There is a sender clock, which may be wrong. There is a server clock which is the time server received the message, which is affected by propagation delay (time it takes to actually send a message, can be large especially if device was offline for some time and the server does greylisting which delay message by minutes). There is a receiver clock which is used to detect if the sender/server clock is in the future and therefore wrong from the receiver perspective. All these clocks may be wrong and in a group with users from multiple servers propagation delays can be very different between each pair of users.

[Raiden-GH]

Thx for the information.
If I understand this correctly, mixed messages should occur more often if the chat runs in "real time" and one partner uses a slow provider? By “real time” I mean that a user reads the messages immediately and responds directly.
Maybe under these circumstances, it might make sense to change the order of the messages afterwards?
At least if the distance in the chat history wouldn't be too large.
For example, if the relevant messages were still visible on the display without scrolling.