onion-lasagna-review

Onion Lasagna Review

Overview

Review Onion Lasagna projects by checking dependency direction, boundary wrapping, validation placement, and test coverage. Findings come first; praise is secondary.

Required Context

Before judging, inspect real files and exports. Use rg, find, sed, and package index.ts files. Do not assume exports, package entry points, or folder conventions.

Load ../../references/layer-checklist.md when the request is a review, audit, "by the book" check, or migration assessment.

Review Procedure

1. Map project shape: packages, bounded contexts, presentation surfaces, read/write trees, and bootstrap roots.
2. Scan domain imports for infra, presentation, framework, database, SDK, and schema leaks.
3. Scan app/use-case imports for concrete infrastructure.
4. Scan route handlers for business logic or direct repository calls.
5. Scan infra adapters for outbound port implementation and error wrapping.
6. Check tests near changed or reviewed layers.
7. Report findings first, ordered by severity.

Useful Scans

Start broad, then inspect matches before judging:

rg -n "from ['\\\"].*(drizzle|schema|infra|presentation|http|graphql)" --glob '*domain*' .
rg -n "new .*Client|axios|fetch\\(" --glob '*app*' --glob '*use-case*' .
rg -n "repository\\.|Repository" --glob '*handler*' --glob '*resolver*' --glob '*route*' .
rg -n "extends BaseOutboundAdapter|createInfraError|InfraError" .
rg -n "describe\\(|it\\(" --glob '*use-case*' --glob '*tests*' .

Common Violations

Symptom	Problem	Fix
Domain imports Drizzle or HTTP code	Inner layer depends on outer layer	Move persistence mapping to infra
Use case imports SDK client	App layer bypasses outbound port	Add port and adapter
Handler queries repository	Presentation owns business flow	Call a use case through route mapping
Repository leaks raw errors	Infra boundary is porous	Wrap with BaseOutboundAdapter or explicit InfraError
Validation only happens in handler	Domain invariant can be bypassed	Validate external input at edge and invariants in domain factories

Output Shape

Use this structure:

## Findings

- [Severity] `path/file.ts`: problem. Why it violates Onion Lasagna. Fix. Verification.

## Good Parts

- Specific pattern that matches Onion Lasagna well.

## Test Gaps

- Missing or weak verification.