Don't load attached files for profile images

Summary:
Ref T8478. I think the cycle is:

  - Conpherence Thread > Loads handle for participant > loads file for profile image > loads attached files to check visibility > loads conpherence thread > ...

So, specifically, someone attached their profile image to a thread or message somewhere.

This breaks the cycle by stopping the attached-files visibility check from happening, since we don't need it. This seemed like the easiest link in the chain to break.

//Ideally//, I think the longer-term and more complete fix here is to stop Conpherence from requiring handles in order to load thread handles (and, generally, having a "handles must not load other handles" rule), but that's not trivial and might not be especially practical.

Test Plan: Will test in production.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8478

Differential Revision: https://secure.phabricator.com/D13216

src/applications/files/query/PhabricatorFileQuery.php

@@ -142,6 +142,14 @@ final class PhabricatorFileQuery
     foreach ($files as $file) {
       $phids = array_keys($edges[$file->getPHID()][$edge_type]);
       $file->attachObjectPHIDs($phids);
+
+      if ($file->getIsProfileImage()) {
+        // If this is a profile image, don't bother loading related files.
+        // It will always be visible, and we can get into trouble if we try
+        // to load objects and end up stuck in a cycle. See T8478.
+        continue;
+      }
+
       foreach ($phids as $phid) {
         $object_phids[$phid] = true;
       }