spring-kotlin-code-review

Spring Kotlin Code Review

Source mapping: Tier 1 critical skill derived from Kotlin_Spring_Developer_Pipeline.md (SK-21).

Mission

Review changes the way a strong Kotlin plus Spring teammate would review them: behavior first, risk first, evidence first.

Optimize for catching bugs, regressions, and missing tests, not for polishing style.

Read In This Order

• Diff or changed files.
• Related tests.
• Configuration or build file changes.
• Impacted controllers, services, repositories, security config, and migrations.
• Project conventions from project-context-ingestion if available.

Review Dimensions

Check every relevant change for:

• transaction boundaries and rollback behavior
• proxy compatibility and self-invocation traps
• bean wiring and configuration safety
• API contract, validation, and serialization correctness
• JPA or repository correctness and performance
• security exposure and authorization drift
• concurrency, retries, and idempotency risks
• observability regressions
• test adequacy and missing failure-path coverage
• Kotlin-specific problems such as !!, unsafe platform types, and misuse of lateinit

Output Contract

Return findings first and order them by severity.

Use this structure:

• Findings: each finding should name the risk, explain the consequence, and point to the relevant file and line when available.
• Open questions or assumptions: only where uncertainty changes the review outcome.
• Summary: only after findings, and only briefly.

If no material findings exist, say so explicitly and still note residual risk or testing gaps.

What Counts As A Real Finding

• A correctness bug.
• A production-risking design choice.
• A likely regression.
• A security or data-consistency hole.
• Missing coverage for a meaningful failure path.

Minor style suggestions are secondary and should never drown out real risk.

Review Heuristics

• Prefer a smaller number of well-supported findings over a long list of weak suspicions.
• Tie every finding to behavior, not only to taste.
• Verify whether the repository's existing conventions intentionally justify an unusual pattern before flagging it.
• Distinguish must fix concerns from consider improving concerns.

Advanced Review Checklist

• Check deploy-order safety. A code change, config change, and migration may each be correct alone but unsafe in rolling deployment order.
• Check backward compatibility of JSON contracts, event schemas, database writes, and feature flags. Additive changes are safer than semantic changes hidden behind the same shape.
• Check cache invalidation, deduplication, retry semantics, and idempotency whenever writes or integrations change.
• Check whether observability changed with the behavior. A new critical path without metrics, logs, or trace propagation is a real operational regression.
• Check whether new repository queries need supporting indexes or whether an innocuous loop creates N+1 behavior.
• Check whether any new async, scheduled, or concurrent path changes transaction scope, MDC propagation, or security context.
• Check build and dependency changes for BOM drift, plugin mismatches, or silent classpath changes.
• Check what was removed, not only what was added. Missing validation, logging, or authorization is often the real regression.

Expert Heuristics

• Read the change as a workflow, not as isolated files. Many Spring bugs live in the seam between controller, service, repository, and config.
• If a finding depends on an assumption, state the assumption and the fastest way to confirm it.
• Prefer findings that are expensive for the team to rediscover in production.
• Use style comments only when they prevent future correctness bugs or materially improve maintainability.

Guardrails

• Do not nitpick naming or formatting when the change contains higher-severity risk.
• Do not invent risks without code evidence.
• Do not praise or summarize before surfacing findings.
• Do not ignore missing tests just because the code "looks straightforward."
• Do not apply generic Java advice without checking Kotlin and Spring specifics.

Quality Bar

A good run of this skill gives the author a short list of concrete, high-signal risks to address.

A bad run reads like a generic lint pass and misses the transactional, proxy, security, or persistence behavior that actually matters.