[CI] RestoreTemplateWithMatchOnlyTextMapperIT test failing

[gmarouli]

While working on #107281 we noticed that when we were running testPartialRestoreSnapshotThatIncludesDataStream and we would include the global state, we would get the assertion error that the cluster state size does not match.

In this #107514 we introduce a test that demonstrates this issue without any other changes. Looking for other similar failures (#59140), we believe the reason is that there is something being mutated on the local node after the restoration. But this is just an assumption.

We are not sure if this is an issue in restore or in mapping, that's why we added both labels. Please feel free to change this accordingly.

Build scan:
https://gradle-enterprise.elastic.co/s/ceaa7hizih32e/tests/:modules:mapper-extras:internalClusterTest/org.elasticsearch.index.mapper.RestoreTemplateWithMatchOnlyTextMapperIT/test

Reproduction line:

./gradlew ':modules:mapper-extras:internalClusterTest' --tests "org.elasticsearch.index.mapper.RestoreTemplateWithMatchOnlyTextMapperIT.test" -Dtests.seed=A1FA43D50CA25035 -Dtests.locale=uk -Dtests.timezone=America/Yellowknife -Druntime.java=21

Applicable branches:
main

Reproduces locally?:
Yes

Failure history:
Failure dashboard for org.elasticsearch.index.mapper.RestoreTemplateWithMatchOnlyTextMapperIT#test

Failure excerpt:

java.lang.AssertionError: cluster state size does not match expected:<4659> but was:<4669>

  at __randomizedtesting.SeedInfo.seed([A1FA43D50CA25035:29AE7C0FA25E3DCD]:0)
  at org.junit.Assert.fail(Assert.java:89)
  at org.junit.Assert.failNotEquals(Assert.java:835)
  at org.junit.Assert.assertEquals(Assert.java:647)
  at org.elasticsearch.test.ESIntegTestCase.ensureClusterStateConsistency(ESIntegTestCase.java:1235)
  at org.elasticsearch.test.ESIntegTestCase.afterInternal(ESIntegTestCase.java:586)
  at org.elasticsearch.test.ESIntegTestCase.cleanUpCluster(ESIntegTestCase.java:2331)
  at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
  at java.lang.reflect.Method.invoke(Method.java:580)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1758)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:1004)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.junit.rules.RunRules.evaluate(RunRules.java:20)
  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$1.evaluate(TestRuleMarkFailure.java:44)
  at org.junit.rules.RunRules.evaluate(RunRules.java:20)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$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$1.evaluate(TestRuleIgnoreTestSuites.java:47)
  at org.junit.rules.RunRules.evaluate(RunRules.java:20)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.lambda$forkTimeoutingTask$0(ThreadLeakControl.java:850)
  at java.lang.Thread.run(Thread.java:1583)

[elasticsearchmachine]

Pinging @elastic/es-search (Team:Search)

[elasticsearchmachine]

Pinging @elastic/es-storage-engine (Team:StorageEngine)

[elasticsearchmachine]

Pinging @elastic/es-distributed (Team:Distributed)

[arteam]

@gmarouli it seems that the test passes you passed wrap the mappings inside _doc.

{
  "_doc": {
    "properties": {
      "@timestamp": {
        "format": "date_optional_time||epoch_millis",
        "type": "date"
      },
      "flag": {
        "type": "boolean"
      },
      "message": {
        "type": "match_only_text"
      }
    }
  }
}

[arteam]

If you store the compressed mapping in Template without _doc, for some reason it reads back the compressed mapping wrapped in _doc.

[arteam]

#78746 seems to be related to this issue

[arteam]

Looks like the core issue is MetadataIndexTemplateService#wrapMappingsIfNecessary and Template#reduceMappings alter the mappings, that's why we end up with templates with different sizes.

[arteam]

Another way to fix the test is to use out.writeString(this.mappings.string()); and CompressedXContent.fromJSON(in.readString()) to store/read mappings but it defeats the purpose of storing them compressed.

[gmarouli]

@arteam thanks for looking into this! I am still a bit baffled why this got triggered by using the type "type": "match_only_text" on non template mapping as well. I will see if I can create a different example.