[jbachorik]

What does this PR do?:

Serialize SearchAbandonReason::ROOT_ENUM_ERROR as root_enum_error in datadog.ReferenceChainAbandoned, instead of unknown. Add an error counter and regression coverage for the encoded reason, the counter increment, and the Java-to-JFR path.

Motivation:

Root-enumeration failures already have a distinct engine reason. Losing that reason during serialization hides why the search stopped.

Additional Notes:

• No JFR field/schema change. Existing abandonment thresholds and retry scheduling remain unchanged.
• Keep RECORDING_END mapped to unknown; recording stop does not enqueue an abandonment event.
• Accepted cost: one counter increment per failed enumeration attempt. Error injection is read only in debug builds; its atomic flag remains in the tracker in release builds.
• TTL deferral policy is unchanged; related work is tracked in PROF-16457.
• Human review is required before merge. Focus on the reason-string contract and the debug-only injection path.
• Sphinx reviewed eafb93e6a..d952104e0 using the existing knowledge graph: no code findings. One INFO note says mutation analysis excluded test files; the tests were executed separately as listed below.

How to test the change?:

./.claude/commands/build-and-summarize \
  :ddprof-lib:gtestDebug :ddprof-test:testDebug \
  -Ptests=ReferenceChainRootEnumErrorTest \
  :ddprof-lib:qualityChecks spotlessCheck

Passed for d952104e0: 1,154 native test cases across 97 binary summaries; the Java test passed with no skips and read one abandonment event. Quality and formatting checks passed. Evidence: build/logs/20261113-184019-_ddprof-lib_gtestDebug.log and the testDebug XML result for ReferenceChainRootEnumErrorTest.

• AbandonedEventSerializesRootEnumErrorReason checks the encoded reason and unknown-value fallback.
• ConsecutiveEnumErrorsAbandonSearch checks error-counter deltas during real tracker passes.
• ReferenceChainRootEnumErrorTest forces enumeration errors and asserts the reason read from the resulting JFR.

For Datadog employees:

• If this PR touches code that signs or publishes builds or packages, or handles
  credentials of any kind, I've requested a security review (run the dd:platform-security-review
  skill, or file a request via the PSEC review form).
  bewaire also runs automatically on every PR.
• This PR doesn't touch any of that.
• JIRA: PROF-16662

[dd-octo-sts]

Scan-Build Report

User:	runner@runnervmccnms
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 all
Clang Version:	Ubuntu clang version 21.1.8 (6ubuntu1)
Date:	Fri Nov 13 17:52:44 2026

Bug Summary

Bug Type	Quantity	Display?
All Bugs	2
Logic error
Dereference of null pointer	1
Unused code
Dead initialization	1

Filter Results by File

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Unused code	Dead initialization	referenceChains.cpp	applyOomRamp	497	1
Logic error	Dereference of null pointer	perfEvents_linux.cpp	unregisterThread	720	26

[dd-octo-sts]

CI Test Results

Run: #43477047680 | Commit: 2f6e4ee | Duration: 20m 0s (longest job)

✅ All 32 test jobs passed

Status Overview

JDK	glibc-aarch64/debug	glibc-amd64/debug	musl-aarch64/debug	musl-amd64/debug
8	-	✅	-	-
8-ibm	-	✅	-	-
8-j9	✅	✅	-	-
8-librca	-	-	✅	✅
8-orcl	-	✅	-	-
11	-	✅	-	-
11-j9	✅	✅	-	-
11-librca	-	-	✅	✅
17	✅	✅	-	-
17-graal	✅	✅	-	-
17-j9	✅	✅	-	-
17-librca	-	-	✅	✅
21	✅	✅	-	-
21-graal	✅	✅	-	-
21-librca	-	-	✅	✅
25	✅	✅	-	-
25-graal	✅	✅	-	-
25-librca	-	-	✅	✅

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Summary: Total: 32 | Passed: 32 | Failed: 0

---

Updated: 2026-11-13 18:15:32 UTC

[dd-octo-sts]

✅ All 40 integration tests passed

📊 Dashboard · 👷 Pipeline · 📦 d952104e

[datadog-official]

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: d952104 | Docs | Give us feedback!}

[jbachorik]

@DataDog review

[datadog-official]

More details

The static review found the ROOT_ENUM_ERROR mapping and bounds check consistent with the enum, with error injection confined to debug builds. No actionable defects were identified.

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