core 2.24.0 got stuck in imap loop

[adbenitez]

2025-11-04 20:37:27.159 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/receive_imf.rs:543: Receiving message "5a814ee6-b31c-4e8f-abc5-7ff464d40776@localhost", seen=false...
2025-11-04 20:37:27.162 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/receive_imf.rs:669: Chat assignment is OneOneChat.
2025-11-04 20:37:27.162 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/securejoin.rs:339: Received secure-join message "vg-request-with-auth".
2025-11-04 20:37:27.164 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/securejoin.rs:498: Fingerprint verified via Auth code.
2025-11-04 20:37:27.166 27204-27596 Conversati...stFragment com.b44t.messenger.beta              I  executing debounced chatlist loading
2025-11-04 20:37:27.167 27204-27231 DeltaChat               com.b44t.messenger.beta              W  [accId=7] src/imap.rs:1480: receive_imf error: error in Secure-Join message handling: Failed to find broadcast shared secret.
2025-11-04 20:37:27.187 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/download.rs:250: Partial download: [❗] [36.86 KiB message]
2025-11-04 20:37:27.189 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/receive_imf.rs:543: Receiving message "5a814ee6-b31c-4e8f-abc5-7ff464d40776@localhost", seen=false...
2025-11-04 20:37:27.190 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/receive_imf.rs:669: Chat assignment is OneOneChat.
2025-11-04 20:37:27.191 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/securejoin.rs:339: Received secure-join message "vg-request-with-auth".
2025-11-04 20:37:27.191 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/securejoin.rs:498: Fingerprint verified via Auth code.
2025-11-04 20:37:27.194 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/imap.rs:774: 5 mails read from "INBOX".
2025-11-04 20:37:27.195 27204-27231 DeltaChat               com.b44t.messenger.beta              W  [accId=7] src/scheduler.rs:417: Failed inbox fetch_idle: fetch_move_delete: fetch_new_messages: fetch_many_msgs: error in Secure-Join message handling: Failed to find broadcast shared secret.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/scheduler.rs:406: Preparing new IMAP session for inbox.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              W  [accId=7] src/imap.rs:316: IMAP got rate limited, waiting for 0h 0m 58s until can connect.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/imap.rs:328: Connecting to IMAP without waiting for ratelimit due to interrupt.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/imap.rs:335: Connecting to IMAP server.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/imap.rs:350: IMAP trying to connect to nine.testrun.org:443:tls.
2025-11-04 20:37:27.196 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/net/dns.rs:134: Using memory-cached DNS resolution for nine.testrun.org.
2025-11-04 20:37:27.197 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/net/dns.rs:180: Resolved nine.testrun.org into 116.202.233.236.
2025-11-04 20:37:27.197 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/net/dns.rs:180: Resolved nine.testrun.org into 2a01:4f8:c014:43c5::1.
2025-11-04 20:37:27.198 27204-27231 DeltaChat               com.b44t.messenger.beta              I  [accId=7] src/imap/client.rs:122: Attempting IMAP connection to nine.testrun.org (116.202.233.236:443).

[link2xt]

So the bug is in the new channel handling introduced in #7268
Core 2.23.0 does not have this bug, it was released before merging.

It fails with receive_imf error: error in Secure-Join message handling: Failed to find broadcast shared secret and gets stuck in infinite loop trying to process the same message over and over again. It is also the same message 5a814ee6-b31c-4e8f-abc5-7ff464d40776@localhost after reconnecting.

Fallback #7222 that should have succeeded after adding partial download seems not to work, likely because partial download failed with the same error. There is an issue #7321 about making it more reliable, but for this issue we need a minimal fix reproducing the problem and fixing receive_imf() to not fail.

[Hocuri]

The cause for this is that it's not possible to add new members to a channel that was created before we updated to the latest core. The solution is to show a proper error message rather than landing in an infinite loop.

[link2xt]

This is fixed with #7401