Summary:
This diff introduces several updates to mail merge to improve the procedure for sending a list of drafts.
Specifically, sending mass email will now:
- Clear mail merge metadata on the drafts that will actually be sent
- Upload attached files only /once/, and reuse those files on the drafts that will actually be sent
- Minimize database writes for new drafts being created
- Will queue a SendManyDraftsTask that will subsequently queue the necessary SendDraftTasks and keep track of them, and notify of any failed tasks
TODO:
- Add state to MailMerge plugin for failed sends and ability to attempt to re send them
Test Plan: - TODO
Reviewers: evan, bengotow, jackie
Reviewed By: bengotow, jackie
Subscribers: jackie
Differential Revision: https://phab.nylas.com/D2973
