diff --git a/src/main/java/com/google/devtools/build/skyframe/KeyToConsolidate.java b/src/main/java/com/google/devtools/build/skyframe/KeyToConsolidate.java
index 0d61ec94a3dfcd..a0ba1ed163de6d 100644
--- a/src/main/java/com/google/devtools/build/skyframe/KeyToConsolidate.java
+++ b/src/main/java/com/google/devtools/build/skyframe/KeyToConsolidate.java
@@ -106,6 +106,7 @@ static SkyKey key(Object obj) {
    * to {@link #op} when decoding an operation emitted by this method.
    */
   static Object create(SkyKey key, Op op, IncrementalInMemoryNodeEntry entry) {
+    Preconditions.checkNotNull(key);
     if (op == ReverseDepsUtility.getOpToStoreBare(entry)) {
       return key;
     }