Add List-* headers to bug/MP/etc. notifications

[Stuart Bishop]

Gmail (amongst other mail readers) allows you to easily filter mailing list traffic by matching the List-Id: header.

We should consider adding List-Id and other List-* headers to our outgoing bugmail so it can be simply filtered and tagged by mail readers.

Choice of the unique List-Id might be problematic. I personally would want a List-Id: for all bugs I'm directly subscribed to, and a different List-Id: for each upstream that I'm a bug contact for.

 - If I'm directly subscribed to a bug, List-Id: stub.person.launchpad.net
 - If I'm a member of the launchpad-dev team, which is the bug contact for soyuz, List-Id: soyuz.project.launchpad.net

I don't know if my preferences would match other peoples though.

[Andrea Corbellini (andrea.corbellini)]

> I don't know if my preferences would match other peoples though.
This would be a great thing for me.

[James Henstridge (jamesh)]

It'd be great to have these headers for other Launchpad mail too such as code review mail, answers, blueprint change notifications, etc.

[Stuart Bishop (stub)]

A quick win would be to add the RFC2369 List-Unsubscribe header. We already include a relevant subscription management URL in the footer of (most? all?) generated emails. Adding this URL as the List-Unsubscribe header would allow email interfaces like GMail to provide big shiny unsubscribe buttons.

[Mike Pontillo (mpontillo)]

It would be great to have something gmail can filter by in the header. For what it's worth, my current (imperfect) workaround is to use this for the filter search:

subject:([Merge])