Currently, if two mails with the same subject line are sent to a given Discourse category, each one creates its own topic with the subject line as its title. This ends up creating multiple topics with the same title, regardless of whether or not the “Allow topics with identical, duplicate titles…” configuration options are selected, which can have the effect of resulting in a multitude of topics with the same title.
Here, what I’m requesting, is for such mail-generated posts to automatically be merged into an existing topic when they share its subject line if the “Allow topics with identical, duplicate titles if the category is different” option is unchecked (or by adding a new “merge posts sent by mail into an existing topic when its subject matches the topic’s title” option). This would have the benefit of avoiding duplicate titles in a category while also permitting multiple mails to accumulate in a single topic when they share a subject line (whether by design or accident).
In practice, this comes up for us when we have scripts that generate posts that are intended to be related to one another under a single topic like “such and such a testing configuration failed” or “someone mentioned xyz on reddit”. It would be ideal if all mails sharing such a subject were grouped under a single topic rather than creating a new topic per mail, each with an identical title. It would also let someone add a new post to a given topic by email without necessarily having to reply to a mail notifying them of a previous post to that topic, for people who might need to write by mail rather than via the web interface for one reason or another.
I think the potential for downsides in cases where humans accidentally send in mails whose subject happens to match an existing topic that they were unaware of is low. Mostly because I presume that if their subject line happens to match a pre-existing topic’s title, it’s due to a similarity of content, so it doesn’t seem like a big problem to have it extend the existing topic rather than create a new one with a duplicate title. Moreover, a site administrator could always check the “allow topics with the same title…” checkbox if they did want the current behavior of having each new mail create a new topic.
This feature would be incredibly useful to our Discourse site, and I suspect likely to others’ as well. Thanks for your consideration, and for all the great engineering that has obviously gone into Discourse.