Five purpose-named mailers (cp_maintenance, cp_provisioning, cp_support,
cp_billing, cp_system) land in config/mail.php as plain static entries —
no query runs to build them. Mail::extend('mailbox', ...) in
AppServiceProvider registers a transport that looks up its mailbox
through MailboxResolver only once a mailer is actually resolved, which
for queued mail is inside the worker at send time, never at boot.
Mutation-tested the brief's own three tests by deleting the MAIL_MAILER
guard from MailboxTransport::delegate(): all three stayed green. They
only exercise __toString()/describe(), a code path separate from the one
that actually sends. Added two tests that reach into delegate() itself
(a bound closure, since it's private) and assert the transport it
actually builds: LogTransport while MAIL_MAILER=log, EsmtpTransport once
it isn't. Re-ran the same mutation against the strengthened suite: it
now fails (EsmtpTransport where LogTransport was expected), then passes
again once reverted.
Verified two things against the installed versions before writing this:
LogTransport takes a Psr\Log\LoggerInterface and Log::channel(null)
resolves to the default channel rather than throwing, and
Mail::extend('mailbox', ...) is read by
MailManager::createSymfonyTransport() via $config['transport'] before it
would fall back to createSmtpTransport() — both matched the brief
exactly, no changes needed there.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>