diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
index a67f221..92c3b39 100644
--- a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
@@ -97,7 +97,7 @@
         persist(DIFF, FileDiffCacheKey.class, FileDiffOutput.class)
             .maximumWeight(10 << 20)
             .weigher(FileDiffWeigher.class)
-            .version(7)
+            .version(8)
             .keySerializer(FileDiffCacheKey.Serializer.INSTANCE)
             .valueSerializer(FileDiffOutput.Serializer.INSTANCE)
             .loader(FileDiffLoader.class);
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
index 3c6d746..76f6eb7 100644
--- a/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
@@ -130,9 +130,16 @@
         .build();
   }
 
+  /**
+   * Create a negative file diff. We use this to cache negative diffs for entries that result in
+   * timeouts.
+   */
   public static FileDiffOutput createNegative(
       String filePath, ObjectId oldCommitId, ObjectId newCommitId) {
-    return empty(filePath, oldCommitId, newCommitId).toBuilder().build();
+    return empty(filePath, oldCommitId, newCommitId)
+        .toBuilder()
+        .negative(Optional.of(true))
+        .build();
   }
 
   /** Returns true if this entity represents an unchanged file between two commits. */