Fix of transaction propagation for empty mono/flux and retry operators

[veklov]

This PR fixes two issues with the project reactor instrumentation

• Transaction is not propagated to Mono.doOnSuccess and Flux.doOnComplete
• Transaction is lost after Mono.retry* re-subscribes while handling an error

[tspring]

Thanks @veklov . This all looks good. Just two minor changes if you don't mind

[tspring]

Would you be OK with setting the default to false and leaving the config in case someone finds it useful

[veklov]

I just wanted to draw your attention to this. No change is necessary if you think it may be useful for someone.

Please also note that there is a similar lifter in spring-webflux instrumentation module. It reports such error unconditionally and expires tokens immediately after linking (one of the issues being fixed in this PR).

newrelic-java-agent/instrumentation/spring-webflux-5.3.0/src/main/java/com/nr/agent/instrumentation/spring/reactive/Util.java

Lines 74 to 92 in 2ff0a81

	@Trace(async = true, excludeFromTransactionTrace = true)
	private void withNRToken(Runnable runnable) {
	Token token = currentContext().get(NR_TOKEN);
	if (token != null) {
	token.linkAndExpire();
	}
	runnable.run();
	}
	@Trace(async = true, excludeFromTransactionTrace = true)
	private void withNRError(Runnable runnable, Throwable throwable) {
	Token token = currentContext().get(NR_TOKEN);
	if (token != null && token.isActive()) {
	token.linkAndExpire();
	NewRelic.noticeError(throwable);
	}
	runnable.run();
	}
	}

I use spring webflux server and spring webclient with reactor-netty within the same application. Given that neither token expiration nor error reporting happens after I apply this PR and configure reactor-netty instrumentation to not report errors, it seems that the webflux's lifter is not used. This creates a lot of confusion for understanding the instrumentation.

[tspring]

Thanks for the pointer, I'll revisit that instrumentation and see if we can't clean it up some

[tspring]

Can you remove or un-ignore all of the ignored tests

[veklov]

Done