Schedulers.isInNonBlockingThread() should return true on EventLoop

[minwoox]

In #1665, we made our EventLoop implement NonBlocking interface so that a user who uses Project Reactor gets a warning log when he/she is using a blocking call on our EventLoops.
We didn't use NonBlocking in Project Reactor, but added it under our own reactor.core.scheduler directory because we didn't want to add the Reactor dependency to the core.
However, it doesn't seem to work so we should fix it.

Sample snippet from @joonhaeng:

@Slf4j
@RestController
public class DemoController {
    @RequestMapping("/test")
    public String test() {
        log.debug("{}",Thread.currentThread().getName());
        log.debug("{}",Thread.currentThread().getClass());
        String test[] = new String[] {"1", "2", "3", "4", "5"};
        return Flux.fromArray(test).blockFirst(); // A warning log should appear.
    }
}

[anuraaga]

This looks like it was a proguard issue up to 0.97.0. The NonBlocking interface is empty and wasn't used anywhere in our code so got stripped away as being a no-op. If you look at the published JAR, it doesn't have the reactor package and the bytecode for EventLoopThread does not reference NonBlocking.

But the issue should already be fixed at HEAD - now we use the NonBlocking interface in our own code

https://github.com/line/armeria/blob/master/core/src/main/java/com/linecorp/armeria/internal/eventloop/EventLoopCheckingUtil.java#L47

so proguard keeps it.

[minwoox]

Ah, I couldn't even imagine that. Thanks!

[ikhoon]

Thanks for the inspection! The mystery is solved. 🕵️‍♀️

[ikhoon]

Already Fixed by #2275