**Build scan:**
https://gradle-enterprise.elastic.co/s/zy3maqdnytk64/tests/:server:test/org.elasticsearch.action.admin.indices.diskusage.TransportAnalyzeIndexDiskUsageActionTests/testRandomLimitConcurrentRequests

**Reproduction line:**
`./gradlew ':server:test' --tests "org.elasticsearch.action.admin.indices.diskusage.TransportAnalyzeIndexDiskUsageActionTests.testRandomLimitConcurrentRequests" -Dtests.seed=38580122459C0704 -Dtests.locale=mt -Dtests.timezone=Asia/Shanghai -Druntime.java=19`

**Applicable branches:**
8.3

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.action.admin.indices.diskusage.TransportAnalyzeIndexDiskUsageActionTests&tests.test=testRandomLimitConcurrentRequests

**Failure excerpt:**
```
java.lang.NullPointerException: Cannot invoke "org.elasticsearch.action.admin.indices.diskusage.IndexDiskUsageStats.getIndexSizeInBytes()" because the return value of "java.util.Map.get(Object)" is null

  at __randomizedtesting.SeedInfo.seed([38580122459C0704:1B67A99AA2E7C41C]:0)
  at org.elasticsearch.action.admin.indices.diskusage.TransportAnalyzeIndexDiskUsageActionTests.testRandomLimitConcurrentRequests(TransportAnalyzeIndexDiskUsageActionTests.java:211)
  at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
  at java.lang.reflect.Method.invoke(Method.java:578)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1758)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:946)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$9.evaluate(RandomizedRunner.java:982)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:996)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:44)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:45)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:375)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:824)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:475)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:955)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:840)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:891)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:902)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:38)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:53)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:47)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:375)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.lambda$forkTimeoutingTask$0(ThreadLeakControl.java:831)
  at java.lang.Thread.run(Thread.java:1596)

```
server/src/test/java/org/elasticsearch/action/admin/indices/diskusage/TransportAnalyzeIndexDiskUsageActionTests.java
r.sendRandomFailure(randomBoolean());
                        } else {
                            long shardSize = between(1, Integer.MAX_VALUE);
                            totalIndexSize.addAndGet(shardSize);
                            r.sendRandomResponse(shardSize, randomBoolean());
                        }
                    }
                } catch (InterruptedException e) {
                    throw new AssertionError(e);
                }
            }
        });
        handlingThread.start();
        ClusterService clusterService = mockClusterService(ClusterState.builder(ClusterState.EMPTY_STATE).nodes(nodes).build());
        TransportAnalyzeIndexDiskUsageAction transportAction = createTransportAction(clusterService, transportService, shardToRoutings);
        Task task = new Task(randomLong(), "transport", "action", "", null, emptyMap());
        TransportAnalyzeIndexDiskUsageAction.LimitingRequestPerNodeBroadcastAction broadcastAction =
            transportAction.new LimitingRequestPerNodeBroadcastAction(task, randomDiskUsageRequest(), requestFuture, maxConcurrentRequests);
        broadcastAction.start();
        try {
            AnalyzeIndexDiskUsageResponse response = requestFuture.actionGet(TimeValue.timeValueSeconds(30));
            assertThat(response.getTotalShards(), equalTo(numberOfShards));
            assertThat(response.getFailedShards(), equalTo(failedShards.size()));
            assertThat(response.getSuccessfulShards(), equalTo(numberOfShards - failedShards.size()));
            assertThat(response.getStats().get("test_index").getIndexSizeInBytes(), equalTo(totalIndexSize.get()));
        } finally {
            stopped.set(true);
            handlingThread.join();
        }
    }