Editing a long message truncates it on synced devices, but no "Show full message" button

[codiflow]

• Operating System: Linux
• Delta Chat Version: 2.49.1

Expected behavior

If I edit messages on one device in my multi-device setup they should always look the same on all devices after being synced successfully.

Actual behavior

This is how it looks on the device I was editing the message multiple times (adding more entries to the list with every edit):

And this is how it looks on the synced device:

It ends with [...] and the rest of the message is not accessible anymore. Editing looks like this on the synced device:

Editing the message again on the device where it is fully readable does not bring up any more content to the synced device. For them it stays inaccessible after a specific point.

❗️ Same issue in Arcane Chat on Android.

Steps to reproduce the problem:

• Send a message to a chat
• Edit the message multiple times until it becomes a long message (long in the sense of large height)
• Look at the same message on the synced device

[nicodh]

This is related to chatmail/core#7718 and can only be solved in core

The current state is:

1. long messages get truncated and show a "Show full message" link in the UI and at the same time can't be edited anymore - technically the message is converted to a multi mime message with a plaintext and a html mime part
2. if a short messages is edited and then becomes a long message the logic of 1. is not applied so the message is never truncated

It seems that might end in a state where the message is truncated but not marked as such on second devices

[nicodh]

Closed in favour of chatmail/core#8249