Kotlin Suspend @Transactional Function Issue

[rmondejar]

Expected Behavior

When an exception that extends kotlin.Throwable is thrown in a Kotlin suspend function, the transaction should be rolled back and the connection should be properly released back to the connection pool.

This would allow other transactions to use the connection and prevent potential resource leaks or deadlocks. The code block that is not being reached should be executed, ensuring that the transaction is either committed if no exceptions occurred, or rolled back if an exception was thrown.

In a nutshell, in the io.micronaut.transaction.async.AsyncUsingSyncTransactionOperations.withTransaction function, this part of the code should be reached:

result.whenComplete((o, throwable) -> {
    if (throwable == null) {
        synchronousTransactionManager.commit(status);
        newResult.complete(o);
    } else {
        try {
            synchronousTransactionManager.rollback(status);
        } catch (Exception e) {
            // Ignore rethrow
        }
        newResult.completeExceptionally(throwable);
    }
});

Actual Behaviour

Micronaut Data fails to evict an active connection when a @transactional suspend function throws an exception extending Throwable, resulting in a new connection being opened for each subsequent request

Steps To Reproduce

1. Environment Setup

• IDE: IntelliJ IDEA 2023.3.6
• Languages: Kotlin 1.9.23, Java 21
• Frameworks: Micronaut 4.4.2, Gradle
• Libraries: Kotlin coroutines 1.8.0

2. Configuration

• Clone the repository : https://github.com/uberall/mn-kotlin-transactional-issue

3. Run

• Execute the test that reproduces the issue with the following command:
  ./gradlew -i test --rerun-tasks --tests "com.example.DemoTest.hikariIssue"

4. See Error
   "Unexpected Exception: io.micronaut.http.client.exceptions.ReadTimeoutException: Read Timeout"

• Observe that an exception that extends kotlin.Throwable in a suspend function causes the transaction to be rolled back, but the connection is not released back to the pool

Environment Information

• Operating System: macOS 14.4.1
• JDK: Temurin 21.0.1

Example Application

https://github.com/uberall/mn-kotlin-transactional-issue

Version

4.4.2

[dstepanov]

Your project is not accessible. Please integrate test-resources for your tests so no docker commands are needed.

[rmondejar]

Your project is not accessible. Please integrate test-resources for your tests so no docker commands are needed.

Sorry, I thought it was public already, that's fixed now 👍

Regarding integrating test-resources is a great tip, we added it as well