On Postgres, a failed operation puts the transaction in an error state
where subsequent operations fail. The previous loop with continue would
keep trying to use a broken transaction. Each user now gets its own
transaction so a single notification failure doesn't affect others.
Refactor functions that created their own sessions when called from
within existing transactions, which caused "database table is locked"
errors in SQLite's shared-cache mode.
Changes:
- Add files.CreateWithSession() to reuse caller's session
- Refactor DeleteBackgroundFileIfExists() to accept session parameter
- Add variadic session parameter to notifications.Notify() and
Notifiable.ShouldNotify() interface
- Update all Notify callers (~17 sites) to pass their session through
- Use files.CreateWithSession in SaveBackgroundFile and NewAttachment
- Fix test code to commit sessions before assertions
- Don't create the mail queue when the mailer is disabled to prevent
`SendMail()` from blocking indefinitely
- Add guard clause in `SendMail()` to return early when mailer is
disabled or queue is nil
- Add test to verify notifications don't block when mailer is disabled
This implements the changes from #1080 with the review feedback
addressed (using `package notifications` instead of `package
notifications_test`).
Closes#1080
kolaente