Fix an issue where PullLocal daemon could spin in an error loop

Summary: Fixes T7106. If you have bad credentials AND you've pushed an "update this repository" message into the queue, the loop above this level ends up resetting the timer every time we go through it, so the daemon spins in a loop failing forever.

Test Plan:
  - Created a repo with bad credentials.
  - Clicekd "updated now" to queue an update message.
  - Saw daemon run in a loop.
  - Applied patch, no loop.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7106

Differential Revision: https://secure.phabricator.com/D11795

src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php

@@ -27,6 +27,7 @@
 final class PhabricatorRepositoryPullLocalDaemon
   extends PhabricatorDaemon {
 
+  private $statusMessageCursor = 0;
 
 /* -(  Pulling Repositories  )----------------------------------------------- */
 
@@ -259,8 +260,25 @@ final class PhabricatorRepositoryPullLocalDaemon
    */
   private function loadRepositoryUpdateMessages() {
     $type_need_update = PhabricatorRepositoryStatusMessage::TYPE_NEEDS_UPDATE;
-    return id(new PhabricatorRepositoryStatusMessage())
-      ->loadAllWhere('statusType = %s', $type_need_update);
+    $messages = id(new PhabricatorRepositoryStatusMessage())->loadAllWhere(
+      'statusType = %s AND id > %d',
+      $type_need_update,
+      $this->statusMessageCursor);
+
+    // Keep track of messages we've seen so that we don't load them again.
+    // If we reload messages, we can get stuck a loop if we have a failing
+    // repository: we update immediately in response to the message, but do
+    // not clear the message because the update does not succeed. We then
+    // immediately retry. Instead, messages are only permitted to trigger
+    // an immediate update once.
+
+    foreach ($messages as $message) {
+      $this->statusMessageCursor = max(
+        $this->statusMessageCursor,
+        $message->getID());
+    }
+
+    return $messages;
   }