Fix application service names beneath inferred proxy spans

[mhlidd]

What Does This Do

Fix application descendant spans incorrectly using the gateway service name when both
DD_TRACE_INFERRED_PROXY_SERVICES_ENABLED and DD_TRACE_REMOVE_INTEGRATION_SERVICE_NAMES_ENABLED are
enabled.

For example, with application service checkout and inferred gateway service gateway.example.com:

• The inferred proxy span correctly uses gateway.example.com.
• The application entry span correctly uses checkout.
• Before this change, application descendants are incorrectly overwritten with gateway.example.com.
• After this change, those descendants retain checkout, including its service-name source.

When the local root is an inferred proxy, skip the root-service override and preserve the service name
and source already resolved for the child span.

Motivation

An inferred proxy identifies an upstream gateway. Its service name should not replace the application
service on downstream application spans when integration service names are removed.

Additional Notes

Contributor Checklist

• Format the title according to the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any other useful labels
• Avoid using close, fix, or any linking keywords when referencing an issue
  Use solves instead, and assign the PR milestone to the issue
• Update the CODEOWNERS file on source file addition, migration, or deletion
• Update public documentation with any new configuration flags or behaviors
• Once approved, use merge queue to merge the PR

Jira ticket: [PROJ-IDENT]

[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	13.96 s	13.87 s	[-0.1%; +1.3%] (no difference)
startup:insecure-bank:tracing:Agent	12.91 s	12.95 s	[-1.0%; +0.4%] (no difference)
startup:petclinic:appsec:Agent	17.12 s	17.03 s	[-0.4%; +1.5%] (no difference)
startup:petclinic:iast:Agent	17.02 s	17.06 s	[-1.0%; +0.5%] (no difference)
startup:petclinic:profiling:Agent	16.53 s	16.70 s	[-1.8%; -0.2%] (maybe better)
startup:petclinic:sca:Agent	17.01 s	16.93 s	[-0.6%; +1.5%] (no difference)
startup:petclinic:tracing:Agent	15.80 s	16.19 s	[-6.7%; +1.8%] (no difference)

Commit: d0f09048 · CI Pipeline · Benchmarking Platform UI

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

[chatgpt-codex-connector]

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[datadog-datadog-prod-us1]

More details

The inferred-proxy check keeps the application service name on child spans. The standard root-span behavior stays unchanged.

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[dd-octo-sts]

/merge

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2026-09-21 13:17:44 UTC ℹ️ Start processing command /merge

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2026-09-21 13:17:50 UTC ℹ️ MergeQueue: pull request added to the queue

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

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2026-09-21 14:19:33 UTC ℹ️ MergeQueue: This merge request was merged