Remove AgentTracer.noopContinuation() sentinel

[mcculls]

Motivation

Call sites now check continuation.context() == Context.root() instead of comparing against a shared singleton, mirroring ThreadLocalContextManager.

This helps with switching between the two context manager approaches, since the checks now don't assume a particular implementation.

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Jira ticket: [PROJ-IDENT]

[mcculls]

@codex review

[datadog-prod-us1-6]

More details

PR removes AgentTracer.noopContinuation() sentinel and migrates all 17 call sites to compare continuation.context() == Context.root(). The semantic change is safe: all code paths are equivalent, the @nonnull contract on captureActiveSpan() prevents NPEs, and the change actually fixes a latent bug where NoopContinuation.context() was incorrectly returning NoopSpan.INSTANCE instead of Context.root(). No regressions identified across continuation-checking patterns in async wrappers (Netty, Jetty, Undertow, MongoDB, HTTP clients).

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[Copilot]

Pull request overview

This PR removes the AgentTracer.noopContinuation() sentinel and standardizes “no-op continuation” detection on continuation.context() == Context.root(), aligning behavior across context manager implementations and easing switching between them.

Changes:

• Remove AgentTracer.noopContinuation() and update call sites to use Context.root() / Java8BytecodeBridge.rootContext() checks.
• Update NoopContinuation to expose a public singleton and return Context.root() from context().
• Adjust core and instrumentation tests to assert against Context.root() instead of a shared continuation instance.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal-api/src/main/java/datadog/trace/bootstrap/instrumentation/api/NoopContinuation.java	Makes NoopContinuation publicly accessible and changes its context() to return Context.root().
internal-api/src/main/java/datadog/trace/bootstrap/instrumentation/api/java/lang/ProcessImplInstrumentationHelpers.java	Replaces sentinel identity check with parentContinuation.context() == Context.root().
internal-api/src/main/java/datadog/trace/bootstrap/instrumentation/api/AgentTracer.java	Removes noopContinuation() API and updates internal no-op capture to use NoopContinuation.INSTANCE.
dd-trace-core/src/test/java/datadog/trace/core/scopemanager/ScopeManagerForkedTest.java	Updates assertions to validate no-op continuations via Context.root().
dd-trace-core/src/main/java/datadog/trace/core/scopemanager/ContinuableScopeManager.java	Switches no-op continuation return paths to reuse NoopContinuation.INSTANCE and adds Context.root() handling in capture(Context).
dd-java-agent/instrumentation/undertow/undertow-2.0/src/main/java/datadog/trace/instrumentation/undertow/UndertowRunnableWrapper.java	Uses continuation.context() != Context.root() to decide whether to wrap.
dd-java-agent/instrumentation/synapse-3.0/src/main/java/datadog/trace/instrumentation/synapse3/SynapseServerWorkerInstrumentation.java	Uses rootContext() bridge for root-context comparison in advice code.
dd-java-agent/instrumentation/synapse-3.0/src/main/java/datadog/trace/instrumentation/synapse3/SynapseClientWorkerInstrumentation.java	Uses rootContext() bridge for root-context comparison in advice code.
dd-java-agent/instrumentation/spring/spring-scheduling-3.1/src/main/java/datadog/trace/instrumentation/springscheduling/SpannedMethodInvocation.java	Uses continuation.context() != Context.root() branching.
dd-java-agent/instrumentation/opentracing/opentracing-0.32/src/test/groovy/OpenTracing32Test.groovy	Updates no-op continuation assertions to check .context() == Context.root().
dd-java-agent/instrumentation/opentracing/opentracing-0.31/src/test/groovy/OpenTracing31Test.groovy	Updates no-op continuation assertions to check .context() == Context.root().
dd-java-agent/instrumentation/netty/netty-promise-4.0/src/main/java/datadog/trace/instrumentation/netty4/promise/ListenerWrapper.java	Uses continuation.context() == Context.root() to skip wrapping.
dd-java-agent/instrumentation/netty/netty-4.1/src/main/java/datadog/trace/instrumentation/netty41/NettyChannelPipelineInstrumentation.java	Uses rootContext() bridge comparison in advice code.
dd-java-agent/instrumentation/netty/netty-4.0/src/main/java/datadog/trace/instrumentation/netty40/NettyChannelPipelineInstrumentation.java	Uses rootContext() bridge comparison in advice code.
dd-java-agent/instrumentation/netty/netty-3.8/src/main/java/datadog/trace/instrumentation/netty38/NettyChannelInstrumentation.java	Uses rootContext() bridge comparison in advice code.
dd-java-agent/instrumentation/mongo/mongo-driver/mongo-driver-4.0/src/main/java/datadog/trace/instrumentation/mongo/CallbackWrapper.java	Updates wrapping condition to check against root context (currently has a Context name-collision issue).
dd-java-agent/instrumentation/jetty/jetty-server/jetty-server-12.0/src/main/java17/datadog/trace/instrumentation/jetty12/JettyRunnableWrapper.java	Uses continuation.context() != Context.root() to decide whether to wrap.
dd-java-agent/instrumentation/apache-httpclient/apache-httpclient-5.0/src/main/java/datadog/trace/instrumentation/apachehttpclient5/TraceContinuedFutureCallback.java	Switches no-op continuation check to parentContinuation.context() == Context.root().
dd-java-agent/instrumentation/apache-httpclient/apache-httpasyncclient-4.0/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/TraceContinuedFutureCallback.java	Switches no-op continuation check to parentContinuation.context() == Context.root().
dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/java/concurrent/Wrapper.java	Uses continuation.context() != Context.root() to decide whether to wrap runnables.

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[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	13.88 s	13.95 s	[-1.2%; +0.3%] (no difference)
startup:insecure-bank:tracing:Agent	12.88 s	13.02 s	[-1.8%; -0.4%] (maybe better)
startup:petclinic:appsec:Agent	17.07 s	16.70 s	[+1.2%; +3.2%] (significantly worse)
startup:petclinic:iast:Agent	16.91 s	16.96 s	[-1.1%; +0.6%] (no difference)
startup:petclinic:profiling:Agent	16.66 s	16.86 s	[-2.3%; -0.1%] (maybe better)
startup:petclinic:sca:Agent	16.98 s	16.86 s	[-0.2%; +1.6%] (no difference)
startup:petclinic:tracing:Agent	16.15 s	15.57 s	[-0.6%; +8.1%] (no difference)

Commit: 0e85a141 · CI Pipeline · Benchmarking Platform UI

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[dd-octo-sts]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-20 18:23:37 UTC ℹ️ Start processing command /merge

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2026-07-20 18:23:41 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in master is approximately 2h (p90).

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2026-07-20 19:32:31 UTC ℹ️ MergeQueue: This merge request was merged