diff --git a/server/src/main/java/org/elasticsearch/cluster/node/DiscoveryNodes.java b/server/src/main/java/org/elasticsearch/cluster/node/DiscoveryNodes.java
index 6f8f680b10a..58e7f3408b4 100644
--- a/server/src/main/java/org/elasticsearch/cluster/node/DiscoveryNodes.java
+++ b/server/src/main/java/org/elasticsearch/cluster/node/DiscoveryNodes.java
@@ -338,7 +338,11 @@ public class DiscoveryNodes extends AbstractDiffable<DiscoveryNodes> implements
         } else {
             ObjectHashSet<String> resolvedNodesIds = new ObjectHashSet<>(nodes.length);
             for (String nodeId : nodes) {
-                if (nodeId.equals("_local")) {
+                if (nodeId == null) {
+                    // don't silence the underlying issue, it is a bug, so lets fail if assertions are enabled
+                    assert nodeId != null : "nodeId should not be null";
+                    continue;
+                } else if (nodeId.equals("_local")) {
                     String localNodeId = getLocalNodeId();
                     if (localNodeId != null) {
                         resolvedNodesIds.add(localNodeId);
diff --git a/server/src/test/java/org/elasticsearch/cluster/node/DiscoveryNodesTests.java b/server/src/test/java/org/elasticsearch/cluster/node/DiscoveryNodesTests.java
index 14da84d4971..8ba1ac84666 100644
--- a/server/src/test/java/org/elasticsearch/cluster/node/DiscoveryNodesTests.java
+++ b/server/src/test/java/org/elasticsearch/cluster/node/DiscoveryNodesTests.java
@@ -75,6 +75,15 @@ public class DiscoveryNodesTests extends ESTestCase {
         }
     }
 
+    public void testResolveNodesNull() {
+        DiscoveryNodes discoveryNodes = buildDiscoveryNodes();
+
+        // if assertions are enabled (should be the case for tests, but not in production), resolving null throws
+        expectThrows(AssertionError.class, () -> discoveryNodes.resolveNodes(Collections.singletonList(null).toArray(new String[0])));
+        expectThrows(AssertionError.class, () -> discoveryNodes.resolveNodes(null, "someNode"));
+        expectThrows(AssertionError.class, () -> discoveryNodes.resolveNodes("someNode", null, "someOtherNode"));
+    }
+
     public void testAll() {
         final DiscoveryNodes discoveryNodes = buildDiscoveryNodes();