Support recurrence within taskchampion

[dluciv]

This enhancement idea comes from the fact that Taskwarrior generates recurring tasks on every device where it is allowed to do it.

I have several desktop and mobile devices. Thus, to keep things consistent, I also run a separate service that periodically executes task sync just to generate recurring tasks.

But taskchampion looks as a right place to perform this action.

May be it is to discuss if it is good functionality for a component which is exactly named as sync server, but it definitely looks as a good functionality for the component which is already used to connect multiple devices.

[djmitche]

(moving to taskchampion -- this repo is the sync server which doesn't have access to task data)

[djmitche]

This is similar to #589, which does the same for hooks (which also have a poor story for where they are and are not executed).

We had some initial discussion about this when we were not planning to be compatible with TaskWarrior. That might be useful background.

There are a bunch of issues relating to recurrence in TaskWarrior, and in fact an abandoned RFC for "recurrence v2", so discussion to date has been around inventing a new recurrence mechanism, probably involving TaskChampion as you've suggested, and then providing a way to migrate from the old to the new mechanism. But, there's a great deal of design work left to do there.