Fix flaky PayloadDispatcherImplTest by stubbing getRootSpan

[AlexeyKuznetsov-DD]

What Does This Do

Stubs getRootSpan() on the PendingTrace stub in PayloadDispatcherImplTest.realSpan() so it returns the real span instead of letting Spock fabricate a dummy on every call.

Motivation

The test flush automatically when data limit is breached was flaky on CI with SpockTimeoutError: Method timed out after 10.00 seconds.

getRootSpan() returns DDSpan (a concrete class with no no-arg constructor). Since it was left unstubbed, every serialization pass in the tight while (!flushed.get()) loop hit Spock's EmptyOrDummyResponse, which tried Class.newInstance() (→ InstantiationException) and fell back to expensive reflection/ByteBuddy. Accumulated across all iterations, this intermittently blew the 10s @Timeout on loaded CI runners.

Additional Notes

Behavior is unchanged: the span is a single-span trace, so it is its own root — getRootSpanContextIfDifferent() still resolves to this. The fix just removes the per-call reflection cost, making the loop fast and deterministic.

Test failed on CI with the following stack trace:

org.spockframework.runtime.SpockTimeoutError: Method timed out after 10.00 seconds

Method timed out after 10.00 seconds
	at java.base@11.0.31/java.lang.Throwable.fillInStackTrace(Throwable.java:787)
	at java.base@11.0.31/java.lang.Throwable.<init>(Throwable.java:270)
	at java.base@11.0.31/java.lang.Exception.<init>(Exception.java:66)
	at java.base@11.0.31/java.lang.ReflectiveOperationException.<init>(ReflectiveOperationException.java:56)
	at java.base@11.0.31/java.lang.InstantiationException.<init>(InstantiationException.java:63)
	at java.base@11.0.31/java.lang.Class.newInstance(Class.java:571)
	at app//org.spockframework.mock.EmptyOrDummyResponse.createEmptyObject(EmptyOrDummyResponse.java:141)
	at app//org.spockframework.mock.EmptyOrDummyResponse.respond(EmptyOrDummyResponse.java:117)
	at app//org.spockframework.mock.IResponseGenerator.lambda$getResponseSupplier$0(IResponseGenerator.java:67)
	at app//org.spockframework.mock.runtime.MockController.handle(MockController.java:60)
	at app//org.spockframework.mock.runtime.JavaMockInterceptor.intercept(JavaMockInterceptor.java:83)
	at app//org.spockframework.mock.runtime.ByteBuddyInterceptorAdapter.interceptNonAbstract(ByteBuddyInterceptorAdapter.java:35)
	at app//datadog.trace.core.DDSpanContext.getRootSpanContextIfDifferent(DDSpanContext.java:584)
	at app//datadog.trace.core.DDSpanContext.getRootSpanContextOrThis(DDSpanContext.java:578)
	at app//datadog.trace.core.DDSpanContext.getSamplingPriority(DDSpanContext.java:644)
	at app//datadog.trace.core.DDSpanContext.processTagsAndBaggage(DDSpanContext.java:1243)
	at app//datadog.trace.core.DDSpanContext.processTagsAndBaggage(DDSpanContext.java:1198)
	at app//datadog.trace.core.DDSpan.processTagsAndBaggage(DDSpan.java:780)
	at app//datadog.trace.common.writer.ddagent.TraceMapperV0_5.map(TraceMapperV0_5.java:82)
	at app//datadog.trace.common.writer.ddagent.TraceMapperV0_5.map(TraceMapperV0_5.java:29)
	at app//datadog.communication.serialization.msgpack.MsgPackWriter.format(MsgPackWriter.java:84)
	at app//datadog.trace.common.writer.PayloadDispatcherImpl.addTrace(PayloadDispatcherImpl.java:71)
	at datadog.trace.common.writer.PayloadDispatcherImplTest.flush automatically when data limit is breached(PayloadDispatcherImplTest.groovy:46)

[datadog-prod-us1-4]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 76.69% (+19.76%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 2c8b8f5 | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.80 s	14.72 s	[-0.6%; +1.6%] (no difference)
startup:insecure-bank:tracing:Agent	13.64 s	13.67 s	[-1.0%; +0.6%] (no difference)
startup:petclinic:appsec:Agent	17.50 s	17.10 s	[+1.3%; +3.4%] (significantly worse)
startup:petclinic:iast:Agent	16.78 s	17.51 s	[-8.5%; +0.2%] (no difference)
startup:petclinic:profiling:Agent	17.17 s	17.34 s	[-2.1%; +0.1%] (no difference)
startup:petclinic:sca:Agent	17.50 s	17.37 s	[-0.1%; +1.7%] (no difference)
startup:petclinic:tracing:Agent	16.42 s	16.23 s	[-3.3%; +5.6%] (no difference)

Commit: 2c8b8f58 · CI Pipeline · Benchmarking Platform UI

---

Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.

[AlexeyKuznetsov-DD]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-07 13:01:07 UTC ℹ️ Start processing command /merge

---

2026-07-07 13:01:11 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in master is approximately 1h (p90).

---

2026-07-07 14:04:49 UTC ℹ️ MergeQueue: This merge request was merged