Avoid final field modification in JUnit5 instrumentation by daniel-mohedano · Pull Request #11752 · DataDog/dd-trace-java

daniel-mohedano · 2026-06-26T10:41:40Z

What Does This Do

Avoids final field modifications in JUnit5 instrumentation by:
- Building a fresh TestTask for every retry, reusing the original parent context, instead of reusing and modifying the original test task. This approach is only supported for versions 5.3.1+.
- Introducing a new TestDescriptor cloning method based on JupiterTestDescriptor#copyIncludingDescendants(UnaryOperator<UniqueId>)}, which also avoids manually setting the generated uniqueId after the cloning. This approach is only supported for versions 5.13+.

Motivation

Avoid failures in future JDKs due to JEP 500: Prepare to Make Final Mean Final.

Additional Notes

Running an example project on JDK26 with JAVA_TOOL_OPTIONS=--illegal-final-field-mutation=debug produced the following logs:

Final field testDescriptor in class org.junit.platform.engine.support.hierarchical.NodeTestTask has been unreflected for mutation ...
Final field node in class org.junit.platform.engine.support.hierarchical.NodeTestTask has been unreflected for mutation ...
Final field uniqueId in class org.junit.platform.engine.support.descriptor.AbstractTestDescriptor has been unreflected for mutation ...
Final field interceptorCall in class org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor has been mutated reflectively ...
Final field methodInfo in class org.junit.jupiter.engine.descriptor.MethodBasedTestDescriptor has been mutated reflectively ...
Final field configuration in class org.junit.jupiter.engine.descriptor.JupiterTestDescriptor has been mutated reflectively ...
...

The build containing the fix doesn't produce the logs.

Contributor Checklist

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- Get more information in this doc

Jira ticket: SDTEST-3867

cit-pr-commenter-54b7da · 2026-06-26T10:51:55Z

Test Environment - sbt-scalatest

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	55.94	55.43	$\color{red}{\blacktriangle}$ +0.51	55.43	$\color{red}{\blacktriangle}$ +0.51	58/192
agentEvpProxy	55.04	n/a	n/a	n/a	n/a	-

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T10:54:47Z

Test Environment - nebula-release-plugin

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	37.76	36.42	$\color{red}{\blacktriangle}$ +1.34	36.42	$\color{red}{\blacktriangle}$ +1.34	31/96
agentless	36.31	35.70	$\color{red}{\blacktriangle}$ +0.61	35.70	$\color{red}{\blacktriangle}$ +0.61	30/95
agentlessCodeCoverage	44.48	43.60	$\color{red}{\blacktriangle}$ +0.88	43.60	$\color{red}{\blacktriangle}$ +0.88	30/95
agentlessLineCoverage	73.29	74.82	$\color{green}{\blacktriangledown}$ -1.53	74.82	$\color{green}{\blacktriangledown}$ -1.53	29/94

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T10:54:55Z

Test Environment - netflix-zuul

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	87.17	86.07	$\color{red}{\blacktriangle}$ +1.10	86.07	$\color{red}{\blacktriangle}$ +1.10	29/140
agentless	80.18	81.05	$\color{green}{\blacktriangledown}$ -0.87	81.05	$\color{green}{\blacktriangledown}$ -0.87	30/140
agentlessCodeCoverage	95.12	95.12	$\color{gray}{\bullet}$ 0.00	95.12	$\color{gray}{\bullet}$ 0.00	29/137
agentlessLineCoverage	111.17	111.62	$\color{green}{\blacktriangledown}$ -0.45	111.62	$\color{green}{\blacktriangledown}$ -0.45	29/137

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T10:56:55Z

Test Environment - pass4s

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	15.78	10.97	$\color{red}{\blacktriangle}$ +4.81	10.13	$\color{red}{\blacktriangle}$ +5.65	29/94
agentless	9.02	10.75	$\color{green}{\blacktriangledown}$ -1.73	9.73	$\color{green}{\blacktriangledown}$ -0.71	29/95
agentlessCodeCoverage	15.09	18.08	$\color{green}{\blacktriangledown}$ -2.99	17.73	$\color{green}{\blacktriangledown}$ -2.64	27/92

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T10:57:51Z

Test Environment - reactive-streams-jvm

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	21.68	21.65	$\color{red}{\blacktriangle}$ +0.03	21.65	$\color{red}{\blacktriangle}$ +0.03	31/145
agentless	18.60	18.45	$\color{red}{\blacktriangle}$ +0.15	18.82	$\color{green}{\blacktriangledown}$ -0.22	30/143
agentlessCodeCoverage	20.70	19.99	$\color{red}{\blacktriangle}$ +0.71	19.99	$\color{red}{\blacktriangle}$ +0.71	29/142
agentlessLineCoverage	30.40	29.82	$\color{red}{\blacktriangle}$ +0.58	29.82	$\color{red}{\blacktriangle}$ +0.58	28/141

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T11:06:13Z

Test Environment - jolokia

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	93.36	93.23	$\color{red}{\blacktriangle}$ +0.13	93.23	$\color{red}{\blacktriangle}$ +0.13	32/100
agentless	89.01	89.58	$\color{green}{\blacktriangledown}$ -0.57	89.58	$\color{green}{\blacktriangledown}$ -0.57	32/100
agentlessCodeCoverage	98.00	99.00	$\color{green}{\blacktriangledown}$ -1.00	99.00	$\color{green}{\blacktriangledown}$ -1.00	30/97
agentlessLineCoverage	97.73	99.00	$\color{green}{\blacktriangledown}$ -1.27	99.00	$\color{green}{\blacktriangledown}$ -1.27	28/95

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T11:10:41Z

Test Environment - okhttp

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	19.68	19.20	$\color{red}{\blacktriangle}$ +0.48	19.59	$\color{red}{\blacktriangle}$ +0.09	33/102
agentless	17.91	18.82	$\color{green}{\blacktriangledown}$ -0.91	19.20	$\color{green}{\blacktriangledown}$ -1.29	33/102
agentlessCodeCoverage	22.88	22.09	$\color{red}{\blacktriangle}$ +0.79	22.09	$\color{red}{\blacktriangle}$ +0.79	32/99
agentlessLineCoverage	45.36	44.48	$\color{red}{\blacktriangle}$ +0.88	44.48	$\color{red}{\blacktriangle}$ +0.88	34/103

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

cit-pr-commenter-54b7da · 2026-06-26T11:38:47Z

Test Environment - sonar-java

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	8.30	12.87	$\color{green}{\blacktriangledown}$ -4.57	15.72	$\color{green}{\blacktriangledown}$ -7.42	31/99
agentless	26.16	19.99	$\color{red}{\blacktriangle}$ +6.17	16.04	$\color{red}{\blacktriangle}$ +10.12	30/98
agentlessCodeCoverage	73.47	86.07	$\color{green}{\blacktriangledown}$ -12.60	87.80	$\color{green}{\blacktriangledown}$ -14.33	30/98
agentlessLineCoverage	139.70	133.64	$\color{red}{\blacktriangle}$ +6.06	141.90	$\color{green}{\blacktriangledown}$ -2.20	28/96

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

datadog-official

More details

Three critical correctness invariants hold: (1) ThrowableCollectorFactoryWrapper is installed on NodeTestTaskContext (shared across all retry tasks), so factory.setSuppressFailures() correctly controls each retry even though currentTask is now a fresh NodeTestTask; (2) AbstractTestDescriptor.setParent() only sets the child's parent reference without addChild(), so the snapshot and retry descriptors are not injected into the parent's children list; (3) legacyCopy's new conditional uniqueId setter is correct — tryShallowClone already copies all fields including uniqueId, so the setter is only needed when the ID actually changes.

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datadog-official · 2026-07-01T11:42:39Z

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 69.73% (+14.70%)

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🔗 Commit SHA: b5ae13c | Docs | Datadog PR Page | Give us feedback!}

cit-pr-commenter-54b7da · 2026-07-01T11:49:10Z

Test Environment - sonar-kotlin

Job Status: 🟢 success

Scenario	This PR (%)	7d median	Δ 7d	30d median	Δ 30d	runs (7d/30d)
agent	13.95	13.40	$\color{red}{\blacktriangle}$ +0.55	13.13	$\color{red}{\blacktriangle}$ +0.82	30/96
agentless	12.12	12.12	$\color{gray}{\bullet}$ 0.00	11.88	$\color{red}{\blacktriangle}$ +0.24	28/94
agentlessCodeCoverage	17.10	15.41	$\color{red}{\blacktriangle}$ +1.69	15.11	$\color{red}{\blacktriangle}$ +1.99	28/94
agentlessLineCoverage	20.52	19.20	$\color{red}{\blacktriangle}$ +1.32	19.20	$\color{red}{\blacktriangle}$ +1.32	28/94

Baseline: median of @test.tracer_overhead on main (gitlab) over the last 7/30 days, per OSS project & scenario. Δ = this PR − baseline median; red ▲ = more overhead, green ▽ = less overhead than baseline.

dd-octo-sts · 2026-07-01T11:49:12Z

🟢 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	13.98 s	13.91 s	[-0.2%; +1.3%] (no difference)
startup:insecure-bank:tracing:Agent	12.84 s	12.95 s	[-1.5%; -0.1%] (maybe better)
startup:petclinic:appsec:Agent	16.87 s	16.79 s	[-0.7%; +1.7%] (no difference)
startup:petclinic:iast:Agent	16.44 s	16.89 s	[-7.0%; +1.6%] (no difference)
startup:petclinic:profiling:Agent	16.28 s	16.86 s	[-8.0%; +1.1%] (no difference)
startup:petclinic:sca:Agent	16.82 s	16.82 s	[-1.1%; +1.1%] (no difference)
startup:petclinic:tracing:Agent	16.05 s	16.03 s	[-0.7%; +1.0%] (no difference)

Commit: b5ae13c3 · 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.

daniel-mohedano · 2026-07-09T10:35:58Z

/merge

gh-worker-devflow-routing-ef8351 · 2026-07-09T10:36:02Z

View all feedbacks in Devflow UI.

2026-07-09 10:36:01 UTC ℹ️ Start processing command /merge

2026-07-09 10:36:06 UTC ℹ️ MergeQueue: pull request added to the queue

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

2026-07-09 11:32:22 UTC ℹ️ MergeQueue: This merge request was merged

feat: avoid final field modifications in junit instrumentation

c73e0a4

daniel-mohedano added type: feature Enhancements and improvements comp: ci visibility Continuous Integration Visibility labels Jun 26, 2026

daniel-mohedano marked this pull request as ready for review June 29, 2026 14:58

daniel-mohedano requested a review from a team as a code owner June 29, 2026 14:58

datadog-official Bot reviewed Jun 29, 2026

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juan-fernandez approved these changes Jun 29, 2026

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Merge branch 'master' into daniel.mohedano/jep-500-junit

b5ae13c

daniel-mohedano mentioned this pull request Jul 3, 2026

Avoid final field modifications in Cucumber and Spock instrumentations #11851

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gh-worker-dd-mergequeue-cf854d Bot merged commit cde4fbf into master Jul 9, 2026
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gh-worker-dd-mergequeue-cf854d Bot deleted the daniel.mohedano/jep-500-junit branch July 9, 2026 11:32

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🟢 Java Benchmark SLOs — All performance SLOs passed

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