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Fix NPE in DatabaseClientDecorator when JDBC connection has no db type - #12371

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Fix NPE in DatabaseClientDecorator when JDBC connection has no db type#12371
dougqh wants to merge 1 commit into
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dougqh/fix-database-client-decorator-npe

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@dougqh dougqh commented Sep 1, 2026 •
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What Does This Do

Guards DatabaseClientDecorator.processDatabaseType() and dbService() against a null dbType, instead of letting them NPE.

CACHE.computeIfAbsent(dbType, NamingEntry::new) returns null for a null key without invoking the producer (FixedSizeCache.computeIfAbsent, internal-api/.../FixedSizeCache.java:71-73). When dbType is null — e.g. JDBCDecorator.onConnection passing a DBInfo.getType() that couldn't be determined — the returned NamingEntry was dereferenced immediately afterward, throwing an NPE inside tracer instrumentation instead of degrading gracefully.

  • processDatabaseType/dbService: check dbType == null up front and return early, rather than inferring the null case from the cache's return value.
  • Added DatabaseClientDecoratorNullDbTypeTest covering both methods with a null dbType.

Motivation

Fixes a NullPointerException reported in Error Tracking (issue, 1300+ occurrences, first seen 2026-02-16, service mainframe-gateway via JDBC instrumentation):

java.lang.NullPointerException
  at DatabaseClientDecorator$NamingEntry.access$000(DatabaseClientDecorator.java:25)
  at DatabaseClientDecorator.processDatabaseType(DatabaseClientDecorator.java:148)
  at JDBCDecorator.onConnection(JDBCDecorator.java:158)

Additional Notes

/techdebt and /perf-review both came back clean: no duplication/complexity concerns, and the null-guards are a strict improvement on the previously-crashing path with no added cost on the normal path.

🤖 Generated with Claude Code

Contributor Checklist

Jira ticket: [PROJ-IDENT]

@dougqh dougqh added tag: ai generated Largely based on code generated by an AI or LLM type: bug fix Bug fix comp: database Database Monitoring labels Sep 1, 2026
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dd-octo-sts Bot commented Sep 1, 2026 •
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🟢 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 13.96 s 13.86 s [-0.2%; +1.5%] (no difference)
startup:insecure-bank:tracing:Agent 12.89 s 12.99 s [-1.7%; +0.1%] (no difference)
startup:petclinic:appsec:Agent 17.00 s 16.88 s [-0.2%; +1.5%] (no difference)
startup:petclinic:iast:Agent 16.94 s 16.91 s [-0.7%; +0.9%] (no difference)
startup:petclinic:profiling:Agent 16.62 s 16.78 s [-2.0%; +0.0%] (no difference)
startup:petclinic:sca:Agent 16.87 s 16.65 s [+0.4%; +2.3%] (maybe worse)
startup:petclinic:tracing:Agent 16.06 s 15.99 s [-0.6%; +1.4%] (no difference)

Commit: 0dd0abed · 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.

@dougqh
dougqh force-pushed the dougqh/fix-database-client-decorator-npe branch from 343288d to bec931e Compare September 2, 2026 01:10
@dougqh @claude
Fix NPE in DatabaseClientDecorator when JDBC connection has no db type
0dd0abe 
processDatabaseType/dbService dereferenced the NamingEntry returned by
CACHE.computeIfAbsent(dbType, NamingEntry::new) without checking for
null. FixedSizeCache.computeIfAbsent returns null for a null key
without invoking the producer, so a null dbType() (e.g. an
undetermined DBInfo.getType()) led to a NullPointerException in
tracing instrumentation instead of a graceful no-op.

Guard on dbType == null directly instead of inferring it from the
cache's return value, and add a test exercising both methods with a
null dbType.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
@dougqh
dougqh force-pushed the dougqh/fix-database-client-decorator-npe branch from bec931e to 0dd0abe Compare September 2, 2026 01:20
@dougqh
dougqh marked this pull request as ready for review September 2, 2026 01:28
@dougqh
dougqh requested a review from a team as a code owner September 2, 2026 01:28
@dougqh
dougqh requested review from bric3 and removed request for a team September 2, 2026 01:28
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datadog-datadog-prod-us1-2 Bot reviewed Sep 2, 2026
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Datadog Autotest: PASS

More details

The null guards prevent both null dereferences. They keep the existing behavior for non-null database types.

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@dougqh
dougqh added this pull request to the merge queue Sep 2, 2026
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dd-octo-sts Bot commented Sep 2, 2026

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/merge

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gh-worker-devflow-routing-ef8351 Bot commented Sep 2, 2026 •
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View all feedbacks in Devflow UI.

2026-09-02 23:49:56 UTC ℹ️ Start processing command /merge

2026-09-02 23:50:01 UTC ℹ️ MergeQueue: pull request added to the queue

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

2026-09-03 00:05:00 UTC ❌ MergeQueue: The build pipeline contains failing jobs for this merge request

Build pipeline has failing jobs for 28d87a9:

⚠️ 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.
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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.

@github-merge-queue
github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Sep 2, 2026
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@sarahchen6 sarahchen6 sarahchen6 approved these changes
@bric3 bric3 Awaiting requested review from bric3 bric3 is a code owner automatically assigned from DataDog/apm-lang-platform-java

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