Both fixes are follow-ups to the mail providers @denkfabrik-li added in #1679.
A refresh token is good for exactly one use — Microsoft and Google both
retire it as they issue the next one. Two queue workers finding the same
expired access token would therefore both spend it, and the loser gets
invalid_grant back. That is the same answer a revoked grant gives, so a
healthy connection would be marked broken, painted red on the settings
page and mailed to every admin. Refreshes now hold a per-connection lock
and whoever waits re-reads the row, which normally means finding a token
the winner already stored and not refreshing at all.
The Connect button read the provider dropdown, but the flow it starts
uses the saved provider. On an installation with both vendors registered,
switching without saving would open the wrong consent screen. The
dropdown now counts as an unsaved change like any other field, which also
gives it the right "save first" hint for free.
It is used by both OAuth mail test files, which --parallel runs in
separate processes — exactly the situation tests/Helpers.php exists
for, as its own header explains. CI caught what a whole-suite serial
run hides.
Adds "Microsoft 365 (OAuth)" to the Email settings provider dropdown.
Selecting it swaps the SMTP form for an app registration (client id,
secret, optional tenant) and a "Connect mailbox" flow: the admin signs
into the mailbox the installation should send as, and outgoing email
goes through Graph sendMail as that mailbox — no password, no app
password, no SMTP AUTH, which Microsoft is winding down.
Delegated flow on purpose: it needs no admin consent and works for
work/school and personal accounts alike. Its one weakness — a grant
can die silently behind a password reset or a Conditional Access
change — is answered by a daily scheduled refresh that keeps the
token alive and, on a dead grant, warns the settings admins once
in-app and on the settings page instead of letting mail stop quietly.
Tokens and the client secret live encrypted in their own row and are
read fresh at send time, never through the boot-config cache. The
stored SMTP transport survives a provider switch untouched.
ignacionelson