diff --git a/src/infrastructure/diff/engine/PhabricatorInlineCommentAdjustmentEngine.php b/src/infrastructure/diff/engine/PhabricatorInlineCommentAdjustmentEngine.php
--- a/src/infrastructure/diff/engine/PhabricatorInlineCommentAdjustmentEngine.php
+++ b/src/infrastructure/diff/engine/PhabricatorInlineCommentAdjustmentEngine.php
@@ -143,7 +143,14 @@
 
     // Find the smallest "new" changeset ID. We'll consider everything
     // larger than this to be "newer", and everything smaller to be "older".
-    $first_new_id = min(mpull($new, 'getID'));
+
+    // (It's possible we have no changesets if the commit is empty.)
+
+    if ($new) {
+      $first_new_id = min(mpull($new, 'getID'));
+    } else {
+      $first_new_id = null;
+    }
 
     $results = array();
     foreach ($inlines as $inline) {