Add FFE flag map adapter coverage

[leoromanovsky]

Motivation

The restored JaCoCo coverage gate exposes that RemoteConfigServiceImpl.FlagMapAdapter and its Moshi factory do not meet the per-class branch and instruction coverage thresholds. That leaves the FFE remote-config flag map deserialization path as one of the remaining blockers for re-enabling coverage verification cleanly.

Changes

This adds focused JUnit coverage for the flag map adapter rather than changing production behavior. The new tests cover the Moshi factory accept/reject paths, null flags payloads, null individual flag entries inside an otherwise valid map, and the read-only toJson path.

Decisions

The adapter stays included in coverage instead of being added to the exclusion list because its behavior is small, stable, and useful to verify: malformed or null flag entries should not prevent other flags in the same remote config payload from being parsed. The tests reuse the same date adapter shape needed by the production Moshi model adapter so the assertions exercise the real deserialization path.

Validation

• ./gradlew :products:feature-flagging:feature-flagging-lib:spotlessApply :products:feature-flagging:feature-flagging-lib:jacocoTestCoverageVerification -PcheckCoverage --console=plain
• ./gradlew :products:feature-flagging:feature-flagging-lib:clean :products:feature-flagging:feature-flagging-lib:jacocoTestCoverageVerification -PcheckCoverage --console=plain

Note: on current master, a clean -PtestJvm=8 -PcheckCoverage run still skips JaCoCo, so this PR fixes the FFE coverage violation while the global testJvm coverage-enablement fix remains separate.

[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	13.91 s	13.95 s	[-1.0%; +0.4%] (no difference)
startup:insecure-bank:tracing:Agent	12.91 s	12.96 s	[-1.2%; +0.5%] (no difference)
startup:petclinic:appsec:Agent	16.76 s	16.65 s	[-0.3%; +1.7%] (no difference)
startup:petclinic:iast:Agent	16.86 s	16.81 s	[-0.4%; +1.0%] (no difference)
startup:petclinic:profiling:Agent	16.85 s	16.87 s	[-1.1%; +0.9%] (no difference)
startup:petclinic:sca:Agent	16.25 s	16.81 s	[-7.5%; +0.8%] (no difference)
startup:petclinic:tracing:Agent	15.63 s	16.12 s	[-7.3%; +1.2%] (no difference)

Commit:4ca643b9 · 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.

2026-06-29 16:48:44 UTC ℹ️ Start processing command /merge

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2026-06-29 16:48:48 UTC ℹ️ MergeQueue: pull request added to the queue

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

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2026-06-29 17:57:48 UTC ℹ️ MergeQueue: This merge request was merged