[mu4e rfe] Restore the old "import to diary" functionality for calendar invites

[phil-s]

Is your feature request related to a problem? Please describe.

I've just updated my OS to Ubuntu 22.04 which has mu 1.6.10.

The old message view mode has a [d]import-in-diary attachment option, which I make heavy use of.

The new message view mode has a fancier-looking system for calendar invites, but appears to be missing the functionality of the old system?

From what I can tell, the new system can optionally import the invite into your diary, but forces you to send an email response.

I never want to send email here. I only want to import the invitation into my diary.

Describe the solution you'd like

In addition to the new buttons for "accepting" and "declining" the invitation, I would like an "import to diary" button.

Describe alternatives you've considered

I've switched back to the old view for now, but I understand that the old view has been removed entirely in newer releases, so that's evidentially not a long-term option.

[djcb]

Assuming the variable diary-file is set, something like this should work with current mu4e:

(add-to-list 'mu4e-view-mime-part-actions
    ;; import into calendar; make sure
    '(:name "dimport-in-diary" :handler (lambda(file) (icalendar-import-file file diary-file))
      :receives temp))

this does not use a button though, you can access it as an action, with A and then choose the text/calendar part.