Mailing list mode: threading is broken

Contribute Bug

AI-generated summary

traut reports a bug in Discourse’s mailing list mode where threading breaks when replying via email. The issue arises because the system generates a new message ID instead of reusing the original one, causing references to be mismatched and resulting in broken thread chains. For example, replies that should continue a thread using the same message ID end up with different IDs, leading to incorrect threading in the forum. martin acknowledges the report and moves the discussion to an existing thread about email threading issues.

1

Hi all, as member of the openstreetmap I found several problems with disourse, which is used for their online forum now.

I was told that the mailing list interface should work very well. However, I found a but that threading becomes broken when you reply by e-mail. Then a new message ID is generated instead of re-using the original ones

Example
The main concept is ok - it used e.g.

format: thread msg-id in-reply-id
1 topic/851.

the initial thread

1.1 topic/851/2747. topic/851

Message 2747 in thread 851 is a reply to initial topic 851, as indicated by the headers in-reply-to: and references:

1.1.1 ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx topic/851/2747.

That’s an e-mail reply to topic/851/2747 with message id ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx

1.1.1.1 topic/851/2749. ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx

Here the forum reply 2749 threads properly to my message-id ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx

1.1.1.1.1 07289952-0e88-c08a-ea66-b34774c8554e@gmx topic/851/2749.

…and so on

However, when I do reply in msg-id ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx to the previous topic, I reference

References:… <topic/851/2747. bae9c8af72f1f7ef599f1bcd @OSM>

But my own message (a HTML forum version) is sent back to me with
References: …
<topic/851/2747. ae42d62b1252f1572b2a9a07 @OSM>

Do you notice the difference within the message id of the references?

The forum’s system does break message ids within references!

This results in broken threads with
1.2 topic/851/2748. topic/851/2747.
1.3 topic/851/2751. topic/851/2749.

where 1.2 is the forum version of 1.1.1 (new message-id topic/851/2748.e6be773dbcc599ad5f35bae5@OSM instead of my original message-id)
and 1.3 is the forum version of 1.1.1.1.1

I did not verify yet whether others receive crippled threads - since they would not receive my original reply with message-id of
1.1.1 ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx,
but would also receive the forum version
1.2 with message id topic/851/2748.e6be773dbcc599ad5f35bae5@OSM, while also receiving reply
1.1.1.1 with references to ee76eed4-a255-6d1c-0f5b-59da9772f230@gmx

I have crippled the domain names here since this forum translates those message IDs to mailto links and thus exceeds my limit of permitted links

2 Likes
Email threading broken
2

Thanks for reporting, I am just going to move this post into the Email threading broken topic.

3 Likes
3

A post was merged into an existing topic: Email threading broken