1 files changed, 12 insertions, 2 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/collect/nestedset/NestedSet.java b/src/main/java/com/google/devtools/build/lib/collect/nestedset/NestedSet.java
index 89db4ecafc..b9e43089c0 100644
--- a/src/main/java/com/google/devtools/build/lib/collect/nestedset/NestedSet.java
+++ b/src/main/java/com/google/devtools/build/lib/collect/nestedset/NestedSet.java
@@ -37,11 +37,11 @@ import javax.annotation.Nullable;
 public final class NestedSet<E> implements Iterable<E> {
 
   private final Order order;
-  private final Object children;
+  final Object children;
   private byte[] memo;
 
   private static final byte[] LEAF_MEMO = {};
-  private static final Object[] EMPTY_CHILDREN = {};
+  static final Object[] EMPTY_CHILDREN = {};
 
   /**
    * Construct an empty NestedSet.  Should only be called by Order's class initializer.
@@ -134,6 +134,16 @@ public final class NestedSet<E> implements Iterable<E> {
     }
   }
 
+  // Only used by deserialization
+  NestedSet(Order order, Object children) {
+    this.order = order;
+    this.children = children;
+    boolean hasChildren =
+        children instanceof Object[]
+            && (Arrays.stream((Object[]) children).anyMatch(child -> child instanceof Object[]));
+    this.memo = hasChildren ? null : LEAF_MEMO;
+  }
+
   /**
    * Returns the ordering of this nested set.
    */