9.18.3 Fancy splitting to parent

Simply put, this lets you put followup e-mail where it belongs.

Every message has a Message-ID, which is unique, and the registry remembers it. When the message is moved or copied, the registry will notice this and offer the new group as a choice to the splitting strategy.

When a followup is made, usually it mentions the original message’s Message-ID in the headers. The registry knows this and uses that mention to find the group where the original message lives. You only have to put a rule like this:

(setq nnimap-my-split-fancy '(|

      ;; split to parent: you need this
      (: gnus-registry-split-fancy-with-parent)

      ;; other rules, as an example
      (: spam-split)
      ;; default mailbox
      "mail")

in your fancy split setup. In addition, you may want to customize the following variables.

Variable: gnus-registry-track-extra

This is a list of symbols, so it’s best to change it from the Customize interface. By default it’s (subject sender recipient), which may work for you. It can be annoying if your mail flow is large and people don’t stick to the same groups.

When you decide to stop tracking any of those extra data, you can use the command gnus-registry-remove-extra-data to purge it from the existing registry entries.

Variable: gnus-registry-split-strategy

This is a symbol, so it’s best to change it from the Customize interface. By default it’s nil, but you may want to set it to majority or first to split by sender or subject based on the majority of matches or on the first found. I find majority works best.