diff --git a/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/SparseFileContent.java b/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/SparseFileContent.java
index a88ebf7b7b..a5373b8fb9 100644
--- a/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/SparseFileContent.java
+++ b/gerrit-prettify/src/main/java/com/google/gerrit/prettify/common/SparseFileContent.java
@@ -170,6 +170,10 @@ public class SparseFileContent {
 
     // Binary search for the range, since we know its a sorted list.
     //
+    if (ranges.isEmpty()) {
+      return null;
+    }
+
     int low = 0;
     do {
       final int mid = (low + high) / 2;