Log at debug when completeSpan methods are used with no active trace

[carterkozak]

Such states suggest that a bug has occurred closing more spans than were opened.

==COMMIT_MSG==
Log at debug when completeSpan methods are used with no active trace
==COMMIT_MSG==

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Type

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• Improvement
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• Manual task
• Migration

Description

Log at debug when completeSpan methods are used with no active trace

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[schlosna]

should we also do this on line 656 as well when there is no open span?

    private static <T> void completeSpanAndNotifyObservers(
            Optional<OpenSpan> openSpan, TagTranslator<? super T> tag, T state, String traceId) {
        //noinspection OptionalIsPresent - Avoid lambda allocation in hot paths
        if (openSpan.isPresent()) {
            Tracer.notifyObservers(toSpan(openSpan.get(), tag, state, traceId));
        } else if (log.isDebugEnabled()) {
            log.debug(
                    "Attempted to complete spans when there is no active Trace. This may be the "
                            + "result of calling completeSpan more times than startSpan",
                    new SafeRuntimeException("not a real exception"));
        }
    }

[carterkozak]

I don't believe that works because Optional<OpenSpan> isn't necessarily present unless the span is sampled:

tracing-java/tracing/src/main/java/com/palantir/tracing/Trace.java

Lines 251 to 258 in eb41f5d

	@Override
	Optional<OpenSpan> pop() {
	validateNumberOfSpans();
	if (numberOfSpans > 0) {
	numberOfSpans--;
	}
	return Optional.empty();
	}

We clear the current trace when the final span is completed, so I don't think that would give us additional coverage.

[schlosna]

good call

[schlosna]

good call

[svc-autorelease]

Released 6.17.0