diff --git a/src/repository/api/ArcanistGitAPI.php b/src/repository/api/ArcanistGitAPI.php
--- a/src/repository/api/ArcanistGitAPI.php
+++ b/src/repository/api/ArcanistGitAPI.php
@@ -1032,6 +1032,11 @@
     // and treat it as though it as a file containing a list of other files,
     // which is silly.
 
+    if (!strlen($path)) {
+      // No filename, so there's no content (Probably new/deleted file).
+      return null;
+    }
+
     list($stdout) = $this->execxLocal(
       'ls-tree %s -- %s',
       $revision,