Guard against null logback events

[amarziali]

What Does This Do

Even I did not found a codepath on logback source that calls callAppenders with a null event, we surface this situation:

Error : Failed to handle exception in instrumentation for ch.qos.logback.classic.Logger - datadog.trace.instrumentation.logback.LogbackLoggerInstrumentation$CallAppendersAdvice
java.lang.NullPointerException
  at (redacted: 9 frames)
  at java.base/java.util.concurrent.ThreadPerTaskExecutor$TaskRunner.run(ThreadPerTaskExecutor.java:314)
  at java.base/java.lang.VirtualThread.run(VirtualThread.java:329)

It can also be a third party. In any case our store is not supporting null keys hence adding this guard for code hygiene.

Motivation

Additional Notes

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
  Use solves instead, and assign the PR milestone to the 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: [PROJ-IDENT]

[datadog-official]

More details

PR adds null-safety guards to two logback instrumentation advice methods. CallAppendersAdvice2 directly calls methods on the event without null checks (getThreadName, getLevel, etc.), so a null event would cause a NullPointerException. CallAppendersAdvice passes the event as a key to WeakMap, which doesn't support null keys. Both guards are defensive and necessary, with no behavioral side effects.

Was this helpful? React 👍 or 👎

_{Open Bits AI session}

_{🤖 Datadog Autotest · Commit f37d1cd · What is Autotest? · Any feedback? Reach out in #autotest}

[datadog-official]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 69.73% (+12.55%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: f37d1cd | Docs | Datadog PR Page | Give us feedback!}

[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	14.03 s	13.99 s	[-0.7%; +1.2%] (no difference)
startup:insecure-bank:tracing:Agent	13.03 s	12.97 s	[-0.3%; +1.3%] (no difference)
startup:petclinic:appsec:Agent	16.80 s	16.72 s	[-0.4%; +1.4%] (no difference)
startup:petclinic:iast:Agent	16.79 s	16.84 s	[-1.0%; +0.5%] (no difference)
startup:petclinic:profiling:Agent	16.57 s	16.58 s	[-1.0%; +0.9%] (no difference)
startup:petclinic:sca:Agent	16.79 s	16.36 s	[-1.9%; +7.2%] (no difference)
startup:petclinic:tracing:Agent	15.62 s	16.13 s	[-7.3%; +1.0%] (no difference)

Commit: f37d1cdc · 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.

[mcculls]

Seems reasonable, although I too would like to know where the null events came from

[dd-octo-sts]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-15 14:16:54 UTC ℹ️ Start processing command /merge

---

2026-07-15 14:16:59 UTC ℹ️ MergeQueue: pull request added to the queue

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

---

2026-07-15 15:22:21 UTC ❌ MergeQueue: The build pipeline contains failing jobs for this merge request

Build pipeline has failing jobs for da28fd1:

• java7-app.arm64.DOC: [public.ecr.aws/lts/ubuntu:22.04, linux/arm64, ]

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

What to do next?

• Investigate the failures and when ready, re-add your pull request to the queue!
• If your PR checks are green, try to rebase/merge. It might be because the CI run is a bit old.
• Any question, go check the FAQ.

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.

[amarziali]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-16 10:22:15 UTC ℹ️ Start processing command /merge

---

2026-07-16 10:22:21 UTC ℹ️ MergeQueue: pull request added to the queue

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

---

2026-07-16 11:20:14 UTC ℹ️ MergeQueue: This merge request was merged