Consider "all account members are disabled" to be a permanent failure when billing a Phortune subscription

Summary:
Fixes T13327. Currently, when we try to bill an account and all members are disabled, we fail temporarily and the task retries forever.

At least for now, just treat this as a permanent failure.

Test Plan:
  - Used `bin/phortune invoice` to generate a normal invoice for a regular subscription.
  - Disabled all the account members, then tried again. Got a helpful permanent failure:

```
$ ./bin/phortune invoice --subscription PHID-PSUB-kbedwt5cyepoc6tohjq5 --auto-range
Set current time to Mon, Jun 24, 2:47 PM.
Preparing to invoice subscription "localb.phacility.com" from Fri, May 31, 10:14 AM to Sun, Jun 30, 10:14 AM.
 WARNING
Manually invoicing will double bill payment accounts if the range overlaps an
existing or future invoice. This script is intended for testing and
development, and should not be part of routine billing operations. If you
continue, you may incorrectly overcharge customers.

    Really invoice this subscription? [y/N] y

[2019-06-24 14:47:57] EXCEPTION: (PhabricatorWorkerPermanentFailureException) All members of the account ("PHID-ACNT-qp54y3unedoaxgkkjpj4") for this subscription ("PHID-PSUB-kbedwt5cyepoc6tohjq5") are disabled. at [<phabricator>/src/applications/phortune/worker/PhortuneSubscriptionWorker.php:88]
arcanist(head=experimental, ref.master=d92fa96366c0, ref.experimental=db4cd55d4673), corgi(head=master, ref.master=6371578c9d32), instances(head=stable, ref.master=ba9e4a19df1c, ref.stable=37fb1f4917c7), libcore(), phabricator(head=master, ref.master=65bc481c91de, custom=11), phutil(head=master, ref.master=7adfe4e4f4a3), services(head=master, ref.master=5424383159ac)
  #0 PhortuneSubscriptionWorker::doWork() called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorWorker.php:124]
  #1 PhabricatorWorker::executeTask() called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorWorker.php:163]
  #2 PhabricatorWorker::scheduleTask(string, array, array) called at [<phabricator>/src/applications/phortune/management/PhabricatorPhortuneManagementInvoiceWorkflow.php:169]
  #3 PhabricatorPhortuneManagementInvoiceWorkflow::execute(PhutilArgumentParser) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:457]
  #4 PhutilArgumentParser::parseWorkflowsFull(array) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:349]
  #5 PhutilArgumentParser::parseWorkflows(array) called at [<phabricator>/scripts/setup/manage_phortune.php:21]
$
```

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13327

Differential Revision: https://secure.phabricator.com/D20613

src/applications/phortune/worker/PhortuneSubscriptionWorker.php

@@ -48,12 +48,15 @@ final class PhortuneSubscriptionWorker extends PhabricatorWorker {
       ->withPHIDs($account->getMemberPHIDs())
       ->execute();
     $actor = null;
+
+    $any_disabled = false;
     foreach ($members as $member) {
 
       // Don't act as a disabled user. If all of the users on the account are
       // disabled this means we won't charge the subscription, but that's
       // probably correct since it means no one can cancel or pay it anyway.
       if ($member->getIsDisabled()) {
+        $any_disabled = true;
         continue;
       }
 
@@ -63,7 +66,26 @@ final class PhortuneSubscriptionWorker extends PhabricatorWorker {
     }
 
     if (!$actor) {
-      throw new Exception(pht('Failed to load actor to bill subscription!'));
+      if ($any_disabled) {
+        $message = pht(
+          'All members of the account ("%s") for this subscription ("%s") '.
+          'are disabled.',
+          $account->getPHID(),
+          $subscription->getPHID());
+      } else if ($account->getMemberPHIDs()) {
+        $message = pht(
+          'Unable to load any of the members of the account ("%s") for this '.
+          'subscription ("%s").',
+          $account->getPHID(),
+          $subscription->getPHID());
+      } else {
+        $message = pht(
+          'The account ("%s") for this subscription ("%s") has no '.
+          'members.',
+          $account->getPHID(),
+          $subscription->getPHID());
+      }
+      throw new PhabricatorWorkerPermanentFailureException($message);
     }
 
     $cart = $account->newCart($actor, $cart_implementation, $merchant);