NPE occurs when AOP is applied to a method that returns CompletableFuture #5741
Description
Describe the bug
Returning null from a method that returns CompletableFuture will result in an NPE in AOP.
@Timed
fun doSomething(): CompletableFuture<Int>? {
return if (condition) {
CompletableFuture.completedFuture(1)
} else {
null
}
}Because AOP considers it to be non-null if it is of type CompletionStage. (code)
As a result, the original method did not cause an NPE, but the AOP caused an NPE, so the calling thread was affected.
If you agree, please let me know if I can create a PR.
Environment
- Micrometer version 1.14.1
- OS: macOS
- Java version: 17
To Reproduce
@SpringBootApplication
class SpringPlaygroundApplication(
private val testComponent: TestComponent
) : ApplicationRunner {
override fun run(args: ApplicationArguments?) {
val result = testComponent.test()
println("result: $result") // No output is produced as NPE is thrown.
Thread.sleep(10000)
}
}
@Configuration
class TestCfg(
private val meterRegistry: MeterRegistry,
) {
@Bean
fun timedAop() = TimedAspect(meterRegistry)
}
fun main(args: Array<String>) {
runApplication<SpringPlaygroundApplication>(*args)
}
@Component
class TestComponent {
@Timed
fun test(): CompletableFuture<Int>? {
return null
}
}
Expected behavior
AOP needs to be aware that values of type CompletionStage can be null.
Also, exceptions raised in AOP should not affect the original method.
Additional context
Add any other context about the problem here, e.g. related issues.