On 2/13/21 4:50 AM, Danil Smirnov wrote:
Hi everyone and Abhilash in particular :)
I've faced a case when Hypirkitty is unable to chain messages into a thread: https://wlug.mailman3.com/hyperkitty/list/wlug@lists.wlug.org/
(See messages with the subject "WLUG Meeting Feb 11th 2021! Topic: Good question!".)
It's a quite disappointment as GMail does show them correctly - as a single thread.
As per my small investigation, a subscriber Robert N. Evans seems to have "In-Reply-To" headers stripped from the messages that probably causes the thread to break.
As Steve notes, threading by Subject: matching has its own issues and HyperKitty makes no attempt to do that.
Where HyperKitty is deficient is it uses only In-Reply-To: and ignores References:. This is an issue if someone sends a reply to an off-list message back to the list. In that case, Hyperkitty doesn't find the In-Reply-To: message-id so starts a new thread, even though there may be References: message-ids in the archive.
I wonder if Hyperkitty is able to leverage some other method to combine the thread correctly in this case?
There is an article on threading at <https://www.jwz.org/doc/threading.html> and an RFC <https://www.rfc-editor.org/rfc/rfc5256.html>. These describe algorithms which are fairly complex, but if someone wanted to try to implement them in HyperKitty, we would certainly consider the implementation.
Note that even HyperKitty's simple method generally works well. It breaks down when replies to off-list messages go back to the list, when user's mail clients don't add In-Reply-To: (these are fairly rare), and when a user composes what is actually a reply as a new message.
Also note that "combine the thread correctly" is a subjective opinion, at least in some cases.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan