Merge "Fix "Failed to reindex changes"" into stable-2.11
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
index 38382aa..8947a38 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/container/HttpAuthFilter.java
@@ -140,7 +140,8 @@
 
   String getRemoteUser(HttpServletRequest req) {
     String remoteUser = RemoteUserUtil.getRemoteUser(req, loginHeader);
-    return userNameToLowerCase ? remoteUser.toLowerCase(Locale.US) : remoteUser;
+    return (userNameToLowerCase && remoteUser != null) ?
+        remoteUser.toLowerCase(Locale.US) : remoteUser;
   }
 
   String getRemoteDisplayname(HttpServletRequest req) {