**Build scan:**
https://gradle-enterprise.elastic.co/s/3iejlt6s5z2gq/tests/:x-pack:plugin:esql:qa:server:single-node:javaRestTest/org.elasticsearch.xpack.esql.qa.single_node.RestEsqlIT/testWarningHeadersOnFailedConversions

**Reproduction line:**
```
./gradlew ':x-pack:plugin:esql:qa:server:single-node:javaRestTest' --tests "org.elasticsearch.xpack.esql.qa.single_node.RestEsqlIT.testWarningHeadersOnFailedConversions" -Dtests.seed=849E06D41F81C775 -Dtests.locale=id-ID -Dtests.timezone=Pacific/Funafuti -Druntime.java=20
```

**Applicable branches:**
main

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

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.xpack.esql.qa.single_node.RestEsqlIT&tests.test=testWarningHeadersOnFailedConversions

**Failure excerpt:**
```
java.lang.AssertionError: 
Expected: is <21>
     but: was <0>

  at __randomizedtesting.SeedInfo.seed([849E06D41F81C775:98FDFE231D426DAD]:0)
  at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
  at org.junit.Assert.assertThat(Assert.java:956)
  at org.junit.Assert.assertThat(Assert.java:923)
  at org.elasticsearch.xpack.esql.qa.rest.RestEsqlTestCase.testWarningHeadersOnFailedConversions(RestEsqlTestCase.java:256)
  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:48)
  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:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:843)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:490)
  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:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.lambda$forkTimeoutingTask$0(ThreadLeakControl.java:850)
  at java.lang.Thread.run(Thread.java:1623)

```
x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/RestEsqlTestCase.java
assertEquals(List.of(List.of(1, 2)), answer.get("values"));
    }
    public void testUseUnknownIndex() throws IOException {
        ResponseException e = expectThrows(ResponseException.class, () -> runEsql(builder().query("from doesNotExist").build()));
        assertEquals(400, e.getResponse().getStatusLine().getStatusCode());
        assertThat(e.getMessage(), containsString("verification_exception"));
        assertThat(e.getMessage(), containsString("Unknown index [doesNotExist]"));
    }
    public void testNullInAggs() throws IOException {
        StringBuilder b = new StringBuilder();
        for (int i = 0; i < 1000; i++) {
            b.append(String.format(Locale.ROOT, """
                {"create":{"_index":"%s"}}
                """, testIndexName()));
            if (i % 10 == 0) {
                b.append(String.format(Locale.ROOT, """
                    {"group":%d}
                    """, i % 2));
            } else {
                b.append(String.format(Locale.ROOT, """
                    {"group":%d,"value":%d}
                    """, i % 2, i));
            }
        }
        Request bulk = new Request("POST", "/_bulk");
        bulk.addParameter("refresh", "true");
        bulk.addParameter("filter_path", "errors");
        bulk.setJsonEntity(b.toString());
        Response response = client().performRequest(bulk);
        assertThat(EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8), equalTo("{\"errors\":false}"));