Affects: 6.1.1+ (Spring Boot 3.2.x)
Reproducer: reproducer.zip

Problem

Calling any suspend function in a service that is proxied by SpringCGLIB might throw an exception due to missing classes in the classpath (java.lang.ClassNotFoundException: org.reactivestreams.Publisher). For some reason this only occurs when another function in the specified class is getting changed too. E.g. if there is an @Transactional method, only then this bug occurs.

Expected Behavior

When calling a suspend function, the call should not be re-written on a non-reactive stack regardeless of other functions in the , similar to how it worked in 6.0.x.

Actual Behavior

When another function in the service forces some new behavior to be introduced by the SpringCGLIB proxy, then the suspend function should be left untouched in a non-reactive application.

Reproducer

reproducer.zip

Crashes with SB 3.2.X, works with SB 3.1.X:

import jakarta.transaction.Transactional import kotlinx.coroutines.runBlocking import org.junit.jupiter.api.Test import org.springframework.beans.factory.annotation.Autowired import org.springframework.boot.autoconfigure.SpringBootApplication import org.springframework.boot.test.context.SpringBootTest import org.springframework.stereotype.Service @SpringBootApplication class DemoCoroutinesCrashApplication @Service class DemoService { @Transactional fun somethingTransaction() { } suspend fun mySuspendFunction(): Int { return 123 } } @SpringBootTest class DemoCoroutinesCrashApplicationTests { @Autowired private lateinit var demoService: DemoService @Test fun `should not crash`(): Unit = runBlocking { demoService.mySuspendFunction() } }