Currently, you may not receive mail when someone, e.g., removes you as a task owner or removes you as a reviewer. We should make sure this mail is delivered.
A simple, general approach is probably:
- Get a list of all recipients before applying changes.
- Apply changes.
- Get a list of all mail recipients after applying changes.
- Send mail to the union of the two lists.
A possibly exceptional case here is users who unsubscribe themselves. We could wait for complaints or special case that.