Latest information from MDS overwrites previous ones

[gerryfrancis]

• Operating System (Linux/Mac/Windows/iOS/Android): Android 10 on Fairphone FP2 (Lineage OS 17.1 build QQ3A.200805.001 from 2021-03-26).

• Delta Chat Version: 1.15.0-beta.

• Expected behavior: When more than one mail from the MDS (Mail Delivery System) arrives for a certain message that could not be delivered, all failures to the corresponding message are summarized.

• Actual behavior: The latest report from the MDS overwrites the previous one(s). The user is not informed that there have been other failures before in delivering the corresponding message.

• Steps to reproduce the problem: This is not very easy to reproduce, but the thing is: -- The first failure report includes something like this:

  <anonymized@example1.com>: Server certificate not verified

  -- The second (and last) failure report includes something like this:

  <anonymized@example2.com>: host mail.example2.com[0.0.0.0] said: 552
  5.2.2 <anonymized@example2.com> Quota exceeded (mailbox for user is full)
  (in reply to end of DATA command)

  (Result: The first information is not displayed to the user.)

• Screenshots: N/A.

• Logs: N/A.

[link2xt]

So currently when we receive an NDN we overwrite the last error each time. Being able to see all received NDNs at last in the message info sounds more correct, but I would say it is low priority for now unless someone comes up with a very simple solution.

[adbenitez]

we now have another API to get read receipts, that is used by desktop already, UIs should use that, preserving the error is more important now, the read receipts are not necessary in the info message anymore

[link2xt]

The issue is not related to read receipts (MDNs) at all and MDNs don't change error messages.

[Septias]

It actually looks like we can easily fix this by just concatenating all nds for instead of generating just one info message:

https://github.com/deltachat/deltachat-core-rust/blob/7b27c8a6cd7369ff013cba631dcfc1c6957dd14f/src/mimeparser.rs#L2203-L2288

[link2xt]

I guess NDNs arrive one after another in two separate messages. E.g. you may receive "user does not exist" for one recipient nearly immediately, then "failed to deliver message" to some unresponsive server week later.

[adbenitez]

The issue is not related to read receipts (MDNs) at all and MDNs don't change error messages.

ah sorry misread, but this is actually happening, it is not only new errors overriding previous one but read receipts also override the error icon in the message with the double checkmark

[iequidoo]

read receipts also override the error icon in the message with the double checkmark

This shouldn't happen anymore, since 1.142.2 Core doesn't update the message state to OutMdnRcvd: a30c6ae1f79490291cc8e355111d0421372cfee1.

[Septias]

If you're sure we can close this as completed, otherwise I can write a test

[iequidoo]

If you're sure we can close this as completed, otherwise I can write a test

NDNs concatenation is still needed, with a test that the resulting error contains both concatenated ones.