Prevent NPE in HttpClientDecorator.isAgentRequest for a null request

[dougqh]

What Does This Do

Guards HttpClientDecorator.isAgentRequest(REQUEST) against a null request, returning false instead of throwing an NPE from inside getRequestHeader. Adds a JUnit 5 regression test.

Motivation

ByteBuddy method advice runs before the instrumented method's own argument validation. So when a caller passes a null HttpRequest (e.g. httpClient.sendAsync(null, bodyHandler)), our SendAsyncAdvice/SendAdvice for the java.net.http instrumentation dereferences it first via isAgentRequest(request) → getRequestHeader(request, ...) and NPEs — before the JDK's own null-check on that same argument ever gets a chance to fire its own, correctly-attributed NPE.

The advice's suppress = Throwable.class keeps this from breaking the caller (the real method still runs afterward and throws its own NPE as expected), but the swallowed exception is logged/recorded as an instrumentation failure ("Failed to handle exception in instrumentation for ... - SendAsyncAdvice"), which is what surfaced this NPE misattributed as an instrumentation bug in Datadog error tracking (issue 83642586-aab1-11f0-a63b-da7ad0900002).

Fixing in the shared HttpClientDecorator base class rather than only in JavaNetClientDecorator so every HTTP client integration built on it is protected the same way.

Additional Notes

techdebt and perf-review skills were run over this branch: no findings from either — isAgentRequest is on the per-request hot path, but the added guard is a single cheap null check with no allocation.

Contributor Checklist

• Format the title according to the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any other useful labels
• Avoid using close, fix, or any linking keywords when referencing an issue
• Update the CODEOWNERS file on source file addition, migration, or deletion
• Update public documentation with any new configuration flags or behaviors
• Once approved, use merge queue to merge the PR

Jira ticket: N/A

[datadog-prod-us1-4]

More details

The null guard stops advice from reading headers from a null request. It preserves the instrumented method's own argument validation.

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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	13.98 s	13.96 s	[-0.5%; +0.8%] (no difference)
startup:insecure-bank:tracing:Agent	12.96 s	12.96 s	[-0.7%; +0.7%] (no difference)
startup:petclinic:appsec:Agent	16.96 s	16.82 s	[-0.1%; +1.7%] (no difference)
startup:petclinic:iast:Agent	16.87 s	16.87 s	[-0.6%; +0.7%] (no difference)
startup:petclinic:profiling:Agent	16.50 s	16.81 s	[-2.7%; -1.0%] (significantly better)
startup:petclinic:sca:Agent	16.40 s	16.75 s	[-6.4%; +2.2%] (no difference)
startup:petclinic:tracing:Agent	16.08 s	16.07 s	[-0.8%; +0.9%] (no difference)

Commit: f7b3f21b · 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.

[dd-octo-sts]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-09-02 12:57:26 UTC ℹ️ Start processing command /merge

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2026-09-02 12:57:32 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in master is approximately 1h (p90).

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2026-09-02 13:15:15 UTC ❌ MergeQueue: The build pipeline contains failing jobs for this merge request

Build pipeline has failing jobs for 310723a:

• check_inst 2/4

⚠️ Do NOT retry failed jobs directly (why?).

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• Investigate the failures and when ready, re-add your pull request to the queue!
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Details

Since those jobs are not marked as being allowed to fail, the pipeline will most likely fail.
Therefore, and to allow other builds to be processed, this merge request has been rejected and the pipeline got canceled.