Andrei, * From: Andrei POPESCU * Date: Mon, 10 Feb 2020 21:43:11 +0200 > Without In-Reply-To a mail reader has no way to which message the reply > belongs, so it's more important than References.
Please look at the Web view of your reply. (If your mailer linkifies this URL, click on it. Otherwise open your browser and copy-paste this URL.) https://lists.debian.org/debian-user/2020/02/msg00375.html In-reply-to and References identifiers are identical. Both are E1j1Dus-00018Y-T8@dalton.invalid. Correct? A Web page isn't email but the Web presentation is consistent with https://tools.ietf.org/html/rfc5322#section-3.6.4 , Identification Fields. [*] Here is an excerpt. > The "In-Reply-To:" field will contain the contents of the > "Message-ID:" field of the message to which this one is a reply (the > parent message"). ... > > The "References:" field will contain the contents of the parent's > "References:" field (if any) followed by the contents of the parent's > "Message-ID:" field (if any). The RFC also mentions the unusual case of a reply to multiple parents. > If there is more than one parent message, then the "In-Reply-To:" > field will contain the contents of all of the parents' "Message-ID:" > fields. But the paragraph for References neglects that case. ("parents'" vs. "parent's") >8~( In debian lists, I've never noticed an instance of multiple identifiers for the In-reply-to field. If you find one, please post a link. (For my taste, one parent per reply is enough. Multiple replies for multiple parents.) So, provided a reply is to only one parent, the last identifier of References is identical to the identifier of In-Reply-To. OK, I'll rise to the bait. Will send a variant of this reply with the In-Reply-To field omitted from the header. If the list software parses References cleverly, it will thread both cases the same. =8~) If the software requires In-Reply-To, the thread will be broken in the variant. >8~( Regards, ... P. [*] Except that the mailing list has "In-reply-to" whereas the RFC sticks to "In-Reply-To". Not too harmful. -- https://en.wikibooks.org/wiki/Medical_Machines https://en.wikibooks.org/wiki/Oberon Tel: +1 604 670 0140 Bcc: peter at easthope. ca