v1: serialize span links as structured data and honor baggage tag config.

[AlexeyKuznetsov-DD]

What Does This Do

Replaces the v1 trace payload's CoreSpan.processTagsAndBaggage(consumer, injectLinksAsTags, injectBaggageAsTags) with a purpose-named processTagsAndBaggageWithStructuredLinks(consumer):

• Span links stay structured — v1 serializes links as first-class data and no longer flattens them into the _dd.span_links tag (injectLinksAsTags = false).
• Baggage-as-tags now follows tracer config — v1 previously hard-coded injectBaggageAsTags = false; it now respects the configured value, aligning v1 with the v0.4/V0.5 paths.
• Drops the now-unused 3-arg overload from CoreSpan (replaced by a default method), DDSpan, DDSpanContext, and the test doubles (SimpleSpan, TraceGenerator).

On the test side:

• Adds real-span v1 coverage in DDSpanSerializationTest.java (structured links not flattened; configured baggage tags).
• Extracts the duplicated msgpack v1 decoder into a shared V1PayloadReader, now used by both DDSpanSerializationTest and TraceMapperV1PayloadTest.

Motivation

system-tests failed on my branch when I enabled v1 by default for tests in Test_Headers_Baggage_Span_Tags.

Additional Notes

Verified:

• ./gradlew :dd-trace-core:test --tests DDSpanSerializationTest --tests TraceMapperV1PayloadTest passes; spotlessApply clean.
• system-tests passed locally: DD_TRACE_DEBUG=true TEST_LIBRARY=java ./run.sh PARAMETRIC tests/parametric/test_headers_baggage.py --force-dd-trace-debug with both modes: v1 or v04 enabled.

[AlexeyKuznetsov-DD]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-01 19:28:13 UTC ℹ️ Start processing command /merge

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2026-07-01 19:28:18 UTC ℹ️ MergeQueue: pull request added to the queue

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

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2026-07-01 21:28:53 UTC ❌ MergeQueue: The build pipeline has timeout

The merge request has been interrupted because the build 5239872126070858024 took longer than expected. The current limit for the base branch 'master' is 120 minutes.

Possible reasons:

• some mandatory checkruns are failing:
  • Check pull request labels
  • Check pull requests
  • Enforce Groovy migration

[AlexeyKuznetsov-DD]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-01 22:25:11 UTC ℹ️ Start processing command /merge

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2026-07-01 22:25:15 UTC ℹ️ MergeQueue: pull request added to the queue

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

---

2026-07-02 00:25:33 UTC ❌ MergeQueue: The build pipeline has timeout

The merge request has been interrupted because the build 7051895293262795330 took longer than expected. The current limit for the base branch 'master' is 120 minutes.

Possible reasons:

• some mandatory checkruns are failing:
  • Check pull request labels
  • Check pull requests
  • Enforce Groovy migration

[datadog-datadog-us1-prod]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 56.45% (-0.53%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 1e4d4ee | 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	14.82 s	14.66 s	[+0.4%; +1.7%] (maybe worse)
startup:insecure-bank:tracing:Agent	13.71 s	13.69 s	[-0.7%; +0.9%] (no difference)
startup:petclinic:appsec:Agent	16.40 s	16.61 s	[-5.9%; +3.4%] (no difference)
startup:petclinic:iast:Agent	16.81 s	16.93 s	[-1.6%; +0.2%] (no difference)
startup:petclinic:profiling:Agent	16.77 s	16.86 s	[-1.7%; +0.5%] (no difference)
startup:petclinic:sca:Agent	16.90 s	16.68 s	[+0.3%; +2.2%] (maybe worse)
startup:petclinic:tracing:Agent	16.15 s	16.09 s	[-0.5%; +1.3%] (no difference)

Commit: 1e4d4ee6 · 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.