Troubleshooting Elasticsearch LongFieldMapperTests Failure

by Viktoria Ivanova 59 views

Hey guys! It looks like we've got a bit of a mystery on our hands with the LongFieldMapperTests specifically the testSyntheticSourceWithTranslogSnapshot test failing in our CI. This issue falls under the elastic and elasticsearch categories, so let's dive deep and figure out what's going on.

Understanding the Failure

So, what exactly is happening? The test is failing with an AssertionError, which essentially means the test expected one thing but got another. Here’s the error message we're seeing:

java.lang.AssertionError: 
Expected: "{\"field\":[-8135279633865072640,3918545411270578176,8864329725765615385]}"
 but: was "{\"field\":[-8135279633865072640,3918545411270578000,8864329725765615385]}"

Notice that the expected and actual JSON outputs are very similar, but there's a slight difference in the second number within the field array. The expected value is 3918545411270578176, but the actual value is 3918545411270578000. That tiny difference is enough to cause the test to fail. It’s like missing a single period in a long document – easy to overlook, but crucial.

This type of error often indicates a problem with data serialization, numerical precision, or some subtle inconsistency in how the data is being processed and stored. Given it involves a long field, we need to consider how these large numbers are being handled in different environments and runs.

Digging into the Details: Build Scans and Reproduction

To get a clearer picture, let’s look at the provided build scans. We have two failing builds:

These scans are invaluable because they provide a detailed look at the build process, including dependencies, configurations, and test executions. By examining these, we can start to pinpoint where the discrepancy might be introduced. For instance, we can check if there are differences in the environment, such as JVM versions or system libraries, that could affect the outcome.

We also have a reproduction line, which is super helpful:

./gradlew ":server:test" --tests "org.elasticsearch.index.mapper.LongFieldMapperTests.testSyntheticSourceWithTranslogSnapshot" -Dtests.seed=62F8C5E53D700A87 -Dtests.locale=kgp-Latn-BR -Dtests.timezone=Africa/Accra -Druntime.java=24

This command allows us to run the failing test in isolation, making it easier to reproduce the issue locally. The -Dtests.seed is particularly interesting because it suggests this test might be sensitive to the random seed used for generating test data. If the test relies on some form of randomness, a specific seed can help us recreate the exact conditions that lead to failure. The -Dtests.locale and -Dtests.timezone parameters point to potential localization issues, where number formatting or date/time handling might be behaving differently. And finally, -Druntime.java=24 specifies the Java runtime version, which is another crucial piece of the puzzle.

Applicable Branches and Reproducibility

This issue is affecting the main branch, which means it’s a pretty high-priority problem since main is typically where the latest development happens. The fact that it reproduces on main suggests that a recent change might be the culprit.

Unfortunately, it's marked as