Remove metamta.send-immediately

Summary:
Ref T3857.

  - Always send mail via daemons. This lets us get rid of this config, and is generally much more performant.
  - After D7964, we warn if daemons aren't running.

Test Plan: Sent some mail.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3857

Differential Revision: https://secure.phabricator.com/D7965

Author: epriestley

conf/default.conf.php

@@ -299,13 +299,6 @@
   'metamta.mail-adapter'        =>
     'PhabricatorMailImplementationPHPMailerLiteAdapter',
 
-  // When email is sent, try to hand it off to the MTA immediately instead of
-  // queueing it for delivery by the daemons. If you are running the Phabricator
-  // daemons with "phd start", you should disable this to provide a (sometimes
-  // substantial) performance boost. It's on by default to make setup and
-  // configuration a little easier.
-  'metamta.send-immediately'    => true,
-
   // When email is sent, what format should Phabricator use for user's
   // email addresses? Valid values are:
   //  - 'short' - 'gwashington <gwashington@example.com>'

src/applications/config/check/PhabricatorSetupCheckExtraConfig.php

@@ -170,6 +170,8 @@ public static function getAncientConfig() {
       'celerity.resource-path' => pht(
         'An alternate resource map is no longer supported. Instead, use '.
         'multiple maps. See T4222.'),
+      'metamta.send-immediately' => pht(
+        'Mail is now always delivered by the daemons.'),
     );
 
     return $ancient_config;

src/applications/config/option/PhabricatorMetaMTAConfigOptions.php

@@ -136,15 +136,6 @@ public function getOptions() {
 custom mailers), consult "Configuring Outbound Email" in the documentation for
 details.
 EODOC
-));
-
-    $immediately_description = $this->deformat(pht(<<<EODOC
-When email is sent, try to hand it off to the MTA immediately instead of
-queueing it for delivery by the daemons. If you are running the Phabricator
-daemons with "phd start", you should disable this to provide a (sometimes
-substantial) performance boost. It's on by default to make setup and
-configuration a little easier.
-EODOC
 ));
 
     $placeholder_description = $this->deformat(pht(<<<EODOC
@@ -298,14 +289,6 @@ public function getOptions() {
           ))
         ->setSummary(pht('Trust "Reply-To" headers for authentication.'))
         ->setDescription($reply_to_description),
-      $this->newOption('metamta.send-immediately', 'bool', true)
-        ->setBoolOptions(
-          array(
-            pht('Send Immediately (Slow)'),
-            pht('Send Via Daemons (Must Run Daemons)'),
-          ))
-        ->setSummary(pht('Improve performance by sending email via daemons.'))
-        ->setDescription($immediately_description),
       $this->newOption('metamta.placeholder-to-recipient', 'string', null)
         ->setSummary(pht('Placeholder for mail with only CCs.'))
         ->setDescription($placeholder_description),

src/applications/metamta/storage/PhabricatorMetaMTAMail.php

@@ -289,25 +289,13 @@ public function setThreadID($thread_id, $is_first_message = false) {
   }
 
   /**
-   * Save a newly created mail to the database and attempt to send it
-   * immediately if the server is configured for immediate sends. When
-   * applications generate new mail they should generally use this method to
-   * deliver it. If the server doesn't use immediate sends, this has the same
-   * effect as calling save(): the mail will eventually be delivered by the
-   * MetaMTA daemon.
+   * Save a newly created mail to the database. The mail will eventually be
+   * delivered by the MetaMTA daemon.
    *
    * @return this
    */
   public function saveAndSend() {
-    $ret = null;
-
-    if (PhabricatorEnv::getEnvConfig('metamta.send-immediately')) {
-      $ret = $this->sendNow();
-    } else {
-      $ret = $this->save();
-    }
-
-    return $ret;
+    return $this->save();
   }
 
   protected function didWriteData() {

src/docs/user/configuration/configuring_outbound_email.diviner

@@ -152,17 +152,6 @@ disable outbound mail, if you don't want to send mail or don't want to configure
 it yet. Just set **metamta.mail-adapter** to
 "PhabricatorMailImplementationTestAdapter".
 
-= Configuring MetaMTA to Send Mail Using a Daemon =
-
-Regardless of how you are sending outbound email, you can move the handoff to
-the MTA out of the main process and into a daemon. This will greatly improve
-application performance if your mailer is slow, like Amazon SES. In particular,
-commenting on Differential Revisions and Maniphest Tasks sends outbound email.
-
-If you set **metamta.send-immediately** to ##false## in your configuration,
-MetaMTA will queue mail to be send by a PhabricatorTaskmasterDaemon.
-For more information on using daemons, see @{article:Managing Daemons with phd}.
-
 = Testing and Debugging Outbound Email =
 
 You can use the `bin/mail` utility to test, debug, and examine outbound mail. In