Skip Drools internal types classloader during transformation

[amarziali]

What Does This Do

Adds DynamicProjectClassLoader$DefaultInternalTypesClassLoader to the existing Drools classloader exclusions.

This prevents classes loaded through the Drools executable-model path from entering the instrumentation-matching pipeline and triggering repeated class-resource scans.

The change includes:

• A focused unit test covering the exact classloader name.
• A real Drools test that generates a declared fact through this classloader and verifies that it is not transformed.
• Existing coverage for compiling and executing Drools rules remains intact.

Motivation

Drools 8 and newer use this internal classloader when defining generated types. Because it was not excluded by default, each new classloader could trigger an expensive instrumentation compatibility scan.

Setting the same classloader through DD_TRACE_CLASSLOADERS_EXCLUDE avoids the overhead. This change makes that behavior the default, consistent with the existing Drools classloader exclusions.

Solves #12469

Additional Notes

Contributor Checklist

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Jira ticket: [PROJ-IDENT]

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-14T07:40:14.427543Z	0298835	PR opened
🔒 Security Review	✅ Completed 2026-09-14T07:41:38.868003Z	0298835	PR opened

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[datadog-datadog-prod-us1-2]

More details

The new exclusion uses the exact Drools internal class loader name. The changed tests cover direct name matching and generated Drools types.

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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	14.83 s	14.70 s	[+0.0%; +1.9%] (maybe worse)
startup:insecure-bank:tracing:Agent	13.51 s	13.68 s	[-1.9%; -0.6%] (maybe better)
startup:petclinic:appsec:Agent	16.94 s	17.35 s	[-6.5%; +1.8%] (no difference)
startup:petclinic:iast:Agent	17.41 s	17.49 s	[-1.3%; +0.3%] (no difference)
startup:petclinic:profiling:Agent	17.44 s	16.72 s	[-0.1%; +8.7%] (no difference)
startup:petclinic:sca:Agent	17.51 s	17.41 s	[-0.3%; +1.6%] (no difference)
startup:petclinic:tracing:Agent	16.44 s	16.64 s	[-2.3%; -0.1%] (maybe better)

Commit: d86ddf0c · 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.