On Tue, 4 Jul 2023 11:40:20 +0200, "Carlos E. R." <robin.listas@telefonica.net> wrote:
On 2023-07-04 11:21, Masaru Nomiya wrote:
[...] Duplicate mails should be determined by the unique Message-ID for each mail.
Not exclusively.
For example, when people reply both to the list and to the person, you get two copies of the same mail, slightly different. Same message-id, different received headers, possibly a different footer and reply to.
An interesting case, that is. If you receive a reply directly to your email address, then it is a personal message to you. But if later, you receive the same message via the list, then they are both a public message. It is like quantum physics. The nature of one is determined by the observation of the other one at some possibly widely separated time and place. Have fun trying to set up a proper filter for that.
My procmail recipe moves one of those to a different folder for direct duped replies.
-- Robert Webb