[reference] reactor-core-3.1 async blind regeneration for #11927 by jordan-wong · Pull Request #11940 · DataDog/dd-trace-java

jordan-wong · 2026-07-14T04:53:08Z

[reference] reactor-core-3.1 blind regeneration for #11927

Reference output from the toolkit's automated instrumentation-authoring
workflow, run against the draft skill in #11927. Not intended to be merged
as-is.

Research context

This PR is part of the async-category research cycle: verifying whether
the current skill draft in #11927 generalizes to Category B
(context-propagation) libraries after the HTTP-cycle skill updates.
reactor-core-3.1 was chosen as the calibration target for non-RxJava
async libraries — Reactor's Publisher/Subscriber chain is a fundamentally
different context-propagation pattern than RxJava's Observer chain, so
this PR tests whether the skill's Cat B guidance generalizes.

Changes applied on top of eval output

Original eval branch inherited a stash-merge revert of #11852 during eval
branch setup, dropping DD_TRACE_ROBOLECTRIC_ENABLED plus 172 unrelated
files. Rebased onto current master by cherry-picking only in-scope paths
under dd-java-agent/instrumentation/reactor-core-3.1/.

Three follow-up fixes were applied on top of the rebased eval output to
unblock local CI-equivalent without hiding the substantive research
signal:

spotless formatting (mechanical, ./gradlew spotlessApply)
removed duplicate ReactorAsyncResultExtension — eval renamed the
package reactor.core.* → reactorcore.* but did not remove the
master's reactor.core.* version, causing runtime AsyncResultExtension
registration conflict across all JVM inst test shards. Fixing this
preserved the package-rename observation (still visible in the PR diff)
without letting a mechanical duplicate obscure it.
dropped Schedulers.elastic() from scheduler test — the generated
scheduler-arg list included Schedulers.elastic() which was deprecated
in Reactor 3.4 and removed in 3.5+, blocking :check (via aggregate
compile) and :latestDepTest (via direct API drift). Removed the
elastic row while keeping parallel and single for coverage of
scheduler-hop trace propagation.

Original: 2e1d2b98d7 → rebased: dbf3d6b2c7 → fixes: 3f485e671e

Where to focus review

The reference output should be compared against the master implementation
to surface how well the current skill draft handles Reactor's
context-propagation model. Known observations for review, ordered by
significance:

Reactor context-propagation classes dropped (PRIMARY finding). The
eval regenerated only 2 of the 7 master instrumentation classes for
this module. Dropped from the eval output:
- ReactorContextBridge — the helper that reads a user-provided span
  from Reactor's own reactor.util.context.Context under the
  dd.span key, adapts it to a Datadog Context, and drives
  context-store-based propagation (capture on subscribe, restore on
  signal, transfer to optimized subscribers).
- BlockingPublisherInstrumentation — advice for Mono.block() /
  Flux.blockFirst() / blockLast() that activates the captured
  context on the blocking-thread side of the chain.
- ContextWritingSubscriberInstrumentation — advice for
  .contextWrite(...) subscribers to capture the user-provided
  context at subscribe time.
- CorePublisherInstrumentation — advice at the base publisher
  interface that hands off context to downstream subscribers.
- OptimizableOperatorInstrumentation — advice for Reactor's
  internal fused-operator path so the captured context survives
  Reactor's operator-chain optimization.
These are the classes that implement Reactor's library-native
context-map propagation mechanism (users pass a span via
.contextWrite(ctx -> ctx.put("dd.span", span))). Without them,
the observer-wrapping pattern the eval did produce (TracingCoreSubscriber,
FluxInstrumentation, MonoInstrumentation) only handles the
Cat-B-generic "capture-restore active context at subscribe" case —
it does NOT handle the Reactor-specific "user placed a span in the
library's context map" case that Spring WebFlux, Spring Kafka
@KafkaListener suspend fun, resilience4j-reactor, reactor-netty,
and other Reactor-adjacent modules rely on.

Concrete failure this causes: spring-messaging-4.0's
KafkaBatchListenerCoroutineTest times out with timed out waiting for async listener to start because the parent spring.consume
span never inherits through the Reactor-mediated coroutine chain.
Similar failures in spring-webflux-6.0:bootTest. See CI failures
under test_inst: [*, 2/8] and test_inst_latest: [*, 4/6] +
[*, 6/6].

Skill-update prescription (candidate for skill(apm-integrations): additional rules from recent HTTP-category PR reviews #11927): add prescriptive
Rule First PR - Implements the Opentracing API #2 guidance for reactive-library regens — when regenerating an
existing Cat B reactive module, enumerate every *Instrumentation.java
in master and preserve or replace each one. For libraries with a
first-class in-library context concept (Reactor's
reactor.util.context.Context, Kotlin's CoroutineContext, JAX-RS
ContainerRequestContext, etc.), also preserve any *ContextBridge-
style helper that reads a well-known key from that library-native
context and populates the toolkit-native ContextStore. Regen must
preserve verbatim or produce equivalent semantics.
Package rename (Rule First PR - Implements the Opentracing API #2, regen-preservation). The eval reorganized
the package layout from datadog.trace.instrumentation.reactor.core
(master) to datadog.trace.instrumentation.reactorcore (eval). The
skill should preserve master's package layout on regen; it did not.
Side-effect: breaks a fully-qualified class reference in
graal-native-image-20.0's NativeImageGeneratorRunnerInstrumentation
(line 158) that listed datadog.trace.instrumentation.reactor.core.ReactorAsyncResultExtension
as build_time.
Version-sensitive tests in the wrong source set. The scheduler
test that broke latestDepTest was generated in src/test/java/
(which compiles against Reactor 3.1) rather than in a
src/latestDepTest/ variant (which would compile against the latest
published version). Master handles this by splitting Reactor
version-sensitive tests into a dedicated latestDepTest source set
(see master's src/latestDepTest/groovy/ReactorCoreTest.groovy).
The skill draft does not currently emit multiple test source sets
for API-drift-sensitive libraries; illustrating this gap is the
underlying reason the Schedulers.elastic() failure occurred.

CI status

Local CI-equivalent (./gradlew :check :muzzle :latestDepTest --no-daemon):
all green after the three fixes above.

Remote CI is intentionally left red to preserve the primary research
signal (observation #1). The 12 failing shards
(test_inst: [17/21/25/tip, 2/8], test_inst_latest: [17/21/25/tip, 4/6],
test_inst_latest: [17/21/25/tip, 6/6]) map deterministically via
dd-trace-java's slot-hash to spring-messaging-4.0 and spring-webflux-6.0
tests that depend on ReactorContextBridge for coroutine / reactive
context propagation. Fixing them would require restoring the 5 dropped
master instrumentation classes, which would hide the finding.

Base: master @ 05671ce3b0

datadog-datadog-us1-prod · 2026-07-14T05:08:25Z

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 57.17% (+0.00%)

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: 3f485e6 | Docs | Datadog PR Page | Give us feedback!}

dd-octo-sts · 2026-07-14T05:16:16Z

🟢 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	14.06 s	13.97 s	[-0.2%; +1.5%] (no difference)
startup:insecure-bank:tracing:Agent	13.01 s	13.05 s	[-1.0%; +0.4%] (no difference)
startup:petclinic:appsec:Agent	16.95 s	16.76 s	[+0.2%; +2.0%] (maybe worse)
startup:petclinic:iast:Agent	16.92 s	16.96 s	[-1.1%; +0.5%] (no difference)
startup:petclinic:profiling:Agent	16.66 s	16.93 s	[-2.4%; -0.7%] (maybe better)
startup:petclinic:sca:Agent	16.96 s	16.82 s	[-0.1%; +1.7%] (no difference)
startup:petclinic:tracing:Agent	16.18 s	16.10 s	[-0.6%; +1.6%] (no difference)

Commit: 3f485e67 · 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.

…skill Automated integration-authoring pass on reactor-core-3.1, produced against the draft skill in #11927. Reference for #11927 reviewers to see concrete output the current skill draft produces. Not intended to be merged as-is. Base: master @ 05671ce (rebased from original 2e1d2b9; the original branch inherited a stash-merge revert of #11852 during eval branch setup that dropped DD_TRACE_ROBOLECTRIC_ENABLED from metadata plus 172 unrelated files. This rebased version cherry-picks ONLY the reactor-core-3.1 module output onto current master, preserving all unrelated upstream changes.) Cost: \$13, reviewer approved with 0 todos remaining. Diff scope: dd-java-agent/instrumentation/reactor-core-3.1/ only. Metadata: no change (all reactor entries already present on master). Note: the toolkit reorganized the package layout from 'datadog.trace.instrumentation.reactor.core' (master) to 'datadog.trace.instrumentation.reactorcore' (eval). This is a regen-preservation Rule #2 concern; documented for reviewer consideration.

jordan-wong · 2026-07-14T12:04:34Z

Rebased 2026-07-14 — branch force-pushed onto current master to fix the shared config-inversion-linter failure (same root cause as PR #11939).

Root cause (not a toolkit bug): the original eval branch inherited a stash-merge revert of #11852 during branch setup. See #11939 comment for the full diagnostic.

Fix: cherry-picked only the in-scope dd-java-agent/instrumentation/reactor-core-3.1/ paths from the original terminal SHA (2e1d2b98d7) onto fresh master (05671ce3b0). All reactor metadata entries were already present on master, so no metadata change is needed.

Result: 24 files changed (all under reactor-core-3.1/), no sibling contamination.

Note for reviewers: the eval reorganized the package layout from datadog.trace.instrumentation.reactor.core (master) to datadog.trace.instrumentation.reactorcore (eval output). This is a Rule #2 (regen-preservation) concern worth flagging — the master module's package layout should typically be preserved verbatim on regen.

Original commit: 2e1d2b98d7 → rebased: dbf3d6b2c7

The 10 CI failures beyond the shared metadata bug are being triaged separately.

Mechanical fix from ./gradlew :dd-java-agent:instrumentation:reactor-core-3.1:spotlessApply to unblock the spotless CI check. No functional changes. Remaining CI failures on this reference PR are preserved as intentional research signal for #11927 reviewers: - test_inst (all JVMs): Rule #2 regen-preservation violation — eval reorganized the package layout from datadog.trace.instrumentation.reactor.core (master) to datadog.trace.instrumentation.reactorcore (eval output), producing a duplicate ReactorAsyncResultExtension registration. - latestDepTest: eval's generated test references Schedulers.elastic() which was removed in Reactor 3.4+; illustrates a latestDep API-drift gap in the current skill draft.

The blind regen produced a new instrumentation class under 'datadog.trace.instrumentation.reactorcore.ReactorAsyncResultExtension' that duplicates the pre-existing master version at 'datadog.trace.instrumentation.reactor.core.ReactorAsyncResultExtension'. Both classes register themselves via static initializer to AsyncResultExtensions.register(), causing runtime conflict and test_inst failures across all JVM shards (17, 21, 25, tip). This commit removes the master leftover so only the eval-generated version remains. The package-rename itself (reactor.core -> reactorcore) is preserved as intentional research signal — it reflects the current PR #11927 draft skill's output and is a Rule #2 (regen-preservation) observation reviewers should see. Remaining failure preserved as expected research signal: - latestDepTest: eval uses Schedulers.elastic() which was removed in Reactor 3.4+; illustrates a latestDep API-drift gap.

The generated ReactorCoreTest.schedulerArgs() included a case using Schedulers.elastic(), which was deprecated in Reactor 3.4 and removed in 3.5+. This blocked both :check (via aggregate test compile) and :latestDepTest (via direct API drift) across all JVM CI shards. Dropped the "elastic" row from the parameterized args, leaving "parallel" and "single" (both present in Reactor 3.1+ and current latestDep). Preserves test coverage of scheduler-hop trace propagation without depending on a removed API. Research observation preserved in the PR body: this failure mode is a latestDep API-drift gap in the current skill draft — master handles version-sensitive tests by splitting them into a separate `latestDepTest` source set (see master's src/latestDepTest/groovy/ReactorCoreTest.groovy).

mcculls · 2026-07-15T12:49:06Z

-  testImplementation project(':dd-java-agent:instrumentation:reactive-streams-1.0')
-  testImplementation project(path: ':dd-java-agent:agent-otel:otel-bootstrap', configuration: 'shadow')
-  testImplementation project(':dd-java-agent:instrumentation:opentelemetry:opentelemetry-1.4')
-  testImplementation project(':dd-java-agent:instrumentation:opentelemetry:opentelemetry-annotations-1.20')


these are for various annotation driven tests

mcculls · 2026-07-15T13:02:47Z

+import reactor.core.publisher.Flux;
+
+public final class FluxInstrumentation
+    implements Instrumenter.ForSingleType, Instrumenter.HasMethodAdvice {


Main thing it wasn't able to recreate is the hand-off via ReactorContextBridge - but TBH that is quite a leap for AI, and that only came about after several human-led revisions of the instrumentation.

It is using context stores and wrapping - but the places it is doing that could lead to increased memory use. Overall I wouldn't say this is the same quality - but I'd be interested to compare the traces it produces against the current approach.

Also it looks not taking into account the general part provided by the reactive-streams module that overlaps with the wrapping part here

@mcculls

…acement guidance Adds two subsections to context-tracking.md driven by reactor-core-3.1 blind regen findings (dd-trace-java PR #11940): 1. **Library-native context maps — the *ContextBridge pattern** (RI-6). Prescribes preservation/regeneration of the Reactor-style context-bridge helper for libraries with a first-class Context concept (Reactor, Kotlin coroutines, JAX-RS, Vert.x). The subscriber-wrapping pattern alone is insufficient — regenerating a reactive module without the bridge silently breaks Spring WebFlux, Spring Kafka reactive, and related downstream libraries. 2. **Wrap placement and context-store lifecycle** (from @mcculls' review of PR #11940). Boundary-only wrapping, Subscriber-lifecycle stores, avoid double-wrapping. Prevents the "increased memory use" pattern the eval output demonstrated. Motivating incident: dd-trace-java PR #11940 eval dropped 5 of 7 master reactor-core-3.1 instrumentation classes including ReactorContextBridge, which caused spring-messaging-4.0's KafkaBatchListenerCoroutineTest to time out. Sources: - @mcculls on PR #11940 FluxInstrumentation.java:20 - docs/eval-research/cycles/2026-07-14-async-cycle-report.md RI-5, RI-6 - Master reference: dd-java-agent/instrumentation/reactor-core-3.1/

@mcculls

… parity Adds three prescriptions to muzzle.md from async cycle iteration-1 findings and @mcculls review feedback. 1. **Namespace-isolation fail block for major-version siblings (RI-2).** rxjava-3.0 master has `muzzle { fail { name = "rxjava2-must-not-match" } }` to assert rxjava3 advice never matches rxjava2 coordinates. Eval dropped the block. Rule prescribes preservation for any module with a prior-major sibling module in the repo. 2. **compileOnly dep version parity on regen (RI-3).** rxjava-3.0 master uses reactive-streams 1.0.3; eval regenerated as 1.0.0, silently narrowing the tested API surface. Rule extends the existing testImplementation parity rule to compileOnly. 3. **Test-scope build.gradle dep preservation (NR-5, @mcculls PR #11940).** reactor-core-3.1 eval dropped 8 testImplementation and latestDepTest deps that back annotation-driven tests and cross-module interop tests. Rule prescribes superset-of-master semantics for test deps.

@mcculls

…w feedback (#11990) skill(apm-integrations): library-native context-map pattern + wrap-placement guidance Adds two subsections to context-tracking.md driven by reactor-core-3.1 blind regen findings (dd-trace-java PR #11940): 1. **Library-native context maps — the *ContextBridge pattern** (RI-6). Prescribes preservation/regeneration of the Reactor-style context-bridge helper for libraries with a first-class Context concept (Reactor, Kotlin coroutines, JAX-RS, Vert.x). The subscriber-wrapping pattern alone is insufficient — regenerating a reactive module without the bridge silently breaks Spring WebFlux, Spring Kafka reactive, and related downstream libraries. 2. **Wrap placement and context-store lifecycle** (from @mcculls' review of PR #11940). Boundary-only wrapping, Subscriber-lifecycle stores, avoid double-wrapping. Prevents the "increased memory use" pattern the eval output demonstrated. Motivating incident: dd-trace-java PR #11940 eval dropped 5 of 7 master reactor-core-3.1 instrumentation classes including ReactorContextBridge, which caused spring-messaging-4.0's KafkaBatchListenerCoroutineTest to time out. Sources: - @mcculls on PR #11940 FluxInstrumentation.java:20 - docs/eval-research/cycles/2026-07-14-async-cycle-report.md RI-5, RI-6 - Master reference: dd-java-agent/instrumentation/reactor-core-3.1/ skill(apm-integrations): strengthen Rule #2 for regen — super(), package, classes, ordering Adds five prescriptions to instrumenter-module.md driven by async cycle iteration-1 findings (docs/eval-research/cycles/2026-07-14-async-cycle-report.md) plus @ygree review feedback on rxjava-3.0 PR #11939. 1. **super() alias strengthening (RI-1)** — concrete rxjava-3.0 example showing DD_TRACE_RXJAVA_3_ENABLED breakage when the version alias is dropped. Existing "preserve super() verbatim" rule was too abstract. 2. **Package layout preservation on regen (RI-4)** — concrete reactor-core-3.1 example showing graal-native-image cross-module reference breakage when the eval renamed reactor.core -> reactorcore. 3. **Enumerate all master *Instrumentation.java classes on regen (RI-5)** — the reactor-core-3.1 regen kept 2 of 7 master classes, silently dropping ReactorContextBridge and 4 others. Rule prescribes an explicit pre-generation enumeration + post-generation diff check. 4. **Preserve declarative-array ordering (NR-1)** — @ygree flagged "meaningless reshuffling" in helperClassNames(). Rule: preserve master's ordering unless a semantic change requires reordering. 5. **Hoist repeated Class.getName() in contextStore() (NR-2)** — @ygree flagged five inlined copies of Context.class.getName() as a regression from master's hoist pattern. Sources: - docs/eval-research/cycles/2026-07-14-async-cycle-report.md RI-1, RI-4, RI-5 - @ygree PR #11939 comments 3591691401, 3591695153 skill(apm-integrations): namespace-isolation fail block + dep version parity Adds three prescriptions to muzzle.md from async cycle iteration-1 findings and @mcculls review feedback. 1. **Namespace-isolation fail block for major-version siblings (RI-2).** rxjava-3.0 master has `muzzle { fail { name = "rxjava2-must-not-match" } }` to assert rxjava3 advice never matches rxjava2 coordinates. Eval dropped the block. Rule prescribes preservation for any module with a prior-major sibling module in the repo. 2. **compileOnly dep version parity on regen (RI-3).** rxjava-3.0 master uses reactive-streams 1.0.3; eval regenerated as 1.0.0, silently narrowing the tested API surface. Rule extends the existing testImplementation parity rule to compileOnly. 3. **Test-scope build.gradle dep preservation (NR-5, @mcculls PR #11940).** reactor-core-3.1 eval dropped 8 testImplementation and latestDepTest deps that back annotation-driven tests and cross-module interop tests. Rule prescribes superset-of-master semantics for test deps. skill(apm-integrations): latestDepTest source set + no banner comments in tests Adds two prescriptions to tests.md from async cycle iteration-1 findings and @ygree review feedback. 1. **latestDepTest source-set preservation (RI-7).** reactor-core-3.1 master has src/latestDepTest/groovy/ for version-sensitive tests. The eval collapsed all tests into src/test/java/, which caused Schedulers.elastic() (removed in Reactor 3.4+) to break :latestDepTest compilation across all JVM shards. Rule prescribes preserving the split when master has it, and using it for libraries with breaking API changes across recent minor versions. 2. **No banner comments in test files (NR-4).** @ygree flagged `// --------- Successful completion ---------` style banners in RxJava3ResultExtensionTest.java as "distracting and don't offer much value because their scope is unclear." Rule: omit or extract into separate test classes with focused Javadoc. skill(apm-integrations): no inline explanatory comments in Advice methods Adds NR-3 from @ygree review of PR #11939. Advice bodies are typically short; the wrapper/helper class is where reviewers look to understand semantics. Duplicating the explanation as a `//`-comment at the advice call site inflates the diff and drifts out of sync with the wrapper's Javadoc. Source: @ygree, PR #11939 comment on SingleInstrumentation.java:55. skill(apm-integrations): address Copilot review on #11990 — latestDepTest nuance, find vs ls glob, muzzle fail scope, ContextStore implementation accuracy skill(apm-integrations): address Codex review on #11990 — 5 P2 comments - context-tracking.md: narrow ContextStore key rule — Reactor uses Publisher/Subscriber; JAX-RS uses ContainerRequestContext; Vert.x uses its own Context; coroutines use Continuation/CoroutineContext. Do not force Reactor's key type onto libraries that don't expose Publisher / Subscriber. Also broaden lifecycle-boundary examples per library shape. - tests.md: distinguish latest-only APIs (belong in src/latestDepTest/) from removed-in-latest APIs (belong in src/test/, or use replacement API in latestDepTest). The Reactor Schedulers.elastic() removal is the removed-in-latest case, not the latest-only case. - muzzle.md #1 (fail-block scope): explicitly show same-coordinate cases (jedis/okhttp/jetty-server) alongside different-coordinate cases (rxjava, jms api). The bounded 'versions' range in the fail block is what asserts non-overlap for same-coordinate siblings. - muzzle.md #2 (test-dep preservation): extend the preservation list to cover testRuntimeOnly / latestDepTestRuntimeOnly / forkedTestRuntimeOnly. Runtime-only test deps do NOT trigger compile failures if dropped, so losing them silently removes cross-instrumentation coexistence coverage (e.g. rxjava-3.0's testRuntimeOnly on rxjava-2.0). - instrumenter-module.md: broaden the pre-regen source-file enumeration from `src/main/java` to every production source set: src/main/java17, src/main/java11, src/main/groovy, src/main/scala, src/main/kotlin. Kafka-clients-3.8 and jetty-server-12.0 keep classes under java17; a `find` limited to `src/main/java` misses them. All five findings are P2 severity per Codex classification; each corrects a case where the iter-2 rule was too narrow and could mislead a regen. skill(apm-integrations): condense regen-preservation content, wire new rules into SKILL.md Feedback from @mcculls on this PR and separately from a senior engineer: async is a hard area where AI output should be a starting point for human+AI iteration, not held to a "perfect on first try" bar. Most of this PR's new content was regen-specific "keep things stable when rewriting" directives, disproportionate for a skill whose SKILL.md is otherwise written entirely for the common case (writing a new integration). 8 of the 12 new sections fell into this category. Collapsed all 8 into a single "editing an existing module" note per file (3 files), each a few sentences: read the current file, preserve what's there unless you have a reason to change it, applies to super()/package/class-set/ordering/dependencies/test-source-sets alike. Kept exactly one concrete example (ReactorContextBridge — the highest-stakes case, since dropping it silently breaks sibling modules that reference the class by FQN) instead of one narrated failure story per rule. Net: ~365 lines added by the PR, ~200 removed here. The 4 sections that are genuine new async-instrumentation content (library-native context maps / *ContextBridge pattern, wrap-placement memory considerations, no-inline-advice-comments, no-banner-comments) are unchanged — those aren't regen-specific, they apply to any reactive library instrumentation, new or edited. Also addresses the Datadog Autotest P1 finding (2026-07-21): the new rules existed in reference files but SKILL.md's per-step pointers were generic ("read this file") rather than pointing at the specific new subsections. Added explicit pointers at Steps 4.1, 5, 7, and 9.2/9.3 so a code-gen LLM sees "read the ContextBridge section" / "add the namespace-isolation fail block" inline in its step-by-step flow instead of needing to discover them by skimming a 200+ line reference file. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> heading fix Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> Potential fix for pull request finding Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> skill(apm-integrations): fix 4 factual errors from Codex review — verified against dd-trace-java source Codex flagged (2026-07-23) that the previous fix broadening the ContextBridge rule beyond Reactor invented plausible-sounding but factually wrong specifics for 3 libraries. Verified each claim against actual dd-trace-java modules before fixing: - JAX-RS: SKILL.md listed it as needing a ContextTracking bridge, but AbstractRequestContextInstrumentation extends InstrumenterModule.Tracing — it's span-owning code, not context-tracking. Removed the JAX-RS mention from SKILL.md and context-tracking.md entirely. - Kotlin coroutines: told agents to key a ContextStore by Continuation/CoroutineContext, but KotlinCoroutinesModule has no contextStore() at all — it uses ThreadContextElement (DatadogThreadContextElement implements ThreadContextElement<Context>). Corrected to point at the actual pattern. - Vert.x: told agents to key by io.vertx.core.Context, but that type is shared across many handler executions on the same Vert.x context — existing vertx-web instrumentation keys per-request state on RoutingContext instead. Keying by core Context would cause cross-request parentage. Corrected to point at RoutingContext. - Reactor wrap-placement: the "prefer subscriber over publisher key" guidance implied these were alternatives, but master's ReactorCoreModule.contextStore() keys BOTH Publisher (via HandoffContext, read before a subscriber exists) AND Subscriber (via Context, for the wrapping pattern) — they're complementary, not a choice. Reworded so the publisher-keyed store is called out as exempt from the "prefer bounded lifetime" optimization. Also fixed a latestDepTest gap Codex found: the prior wording said to put removed-in-latest-version tests in src/test/, but that's only safe when the module uses addTestSuite('latestDepTest') with separate sources. Modules using addTestSuiteForDir('latestDepTest', 'test') reuse src/test/ for both suites, so a removed-API test placed there still gets compiled against latestDepTestImplementation and fails the same way. Split the guidance by which build.gradle wiring the module uses. Root cause: the earlier fix (responding to a prior Codex comment about Reactor-only bias) generalized to other libraries from category-level reasoning ("JAX-RS surely uses a context map like Reactor does") rather than reading those libraries' actual dd-trace-java modules first. Fixed per the java-eval-research skill's canonical-first rule: don't publish a claim about library-specific behavior without checking the source. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Merge branch 'master' into feat/skill-async-iteration-2 Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

jordan-wong mentioned this pull request Jul 14, 2026

skill(apm-integrations): additional rules from recent HTTP-category PR reviews #11927

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jordan-wong added type: feature Enhancements and improvements inst: reactor Reactor instrumentation labels Jul 14, 2026

jordan-wong force-pushed the eval/reactor-core-3.1-async-blind-regen-20260714 branch from 2e1d2b9 to dbf3d6b Compare July 14, 2026 12:04

jordan-wong added 2 commits July 14, 2026 09:05

jordan-wong added tag: do not merge Do not merge changes and removed type: feature Enhancements and improvements labels Jul 14, 2026

mcculls reviewed Jul 15, 2026

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This was referenced Jul 16, 2026

[reference] reactor-core-3.1 iteration-2 regen against skill-async-iteration-2 #11974

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skill(apm-integrations): async instrumentation - add rules from review feedback #11990

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[reference] reactor-core-3.1 async blind regeneration for #11927 - #11940

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mcculls Jul 15, 2026

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amarziali Jul 16, 2026

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jordan-wong commented Jul 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Changes applied on top of eval output

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datadog-datadog-us1-prod Bot commented Jul 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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dd-octo-sts Bot commented Jul 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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🟢 Java Benchmark SLOs — All performance SLOs passed

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jordan-wong commented Jul 14, 2026

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mcculls Jul 15, 2026

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jordan-wong commented Jul 14, 2026 •

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datadog-datadog-us1-prod Bot commented Jul 14, 2026 •

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