Merge "gr-main-header: Fix issue with sidebar not closing if you click on account dropdown" into stable-3.13

java/com/google/gerrit/server/patch/DiffUtil.java

diff --git a/java/com/google/gerrit/server/patch/DiffUtil.java b/java/com/google/gerrit/server/patch/DiffUtil.java
index ef6f029..8f06019 100644
--- a/java/com/google/gerrit/server/patch/DiffUtil.java
+++ b/java/com/google/gerrit/server/patch/DiffUtil.java
@@ -55,6 +55,9 @@
    */
   public static ImmutableList<ModifiedFile> mergeRewrittenModifiedFiles(
       List<ModifiedFile> modifiedFiles) {
+    if (modifiedFiles == null) {
+      return ImmutableList.of();
+    }
     ImmutableList.Builder<ModifiedFile> result = ImmutableList.builder();
     ListMultimap<String, ModifiedFile> byPath = ArrayListMultimap.create();
     modifiedFiles.stream()