basui01/check-cross-layer

Cross-Layer Check

Check if your changes considered all dimensions. Most bugs come from "didn't think of it", not lack of technical skill.

Note: This is a post-implementation safety net. Ideally, read the Pre-Implementation Checklist before writing code.

---

Related Documents

| Document | Purpose | Timing | |----------|---------|--------| | Pre-Implementation Checklist | Questions before coding | Before writing code | | Code Reuse Thinking Guide | Pattern recognition | During implementation | | $check-cross-layer (this skill) | Verification check | After implementation |

---

Execution Steps

1. Identify Change Scope

git status
git diff --name-only

2. Select Applicable Check Dimensions

Based on your change type, execute relevant checks below:

---

Dimension A: Cross-Layer Data Flow (Required when 3+ layers)

Trigger: Changes involve 3 or more layers

| Layer | Common Locations | |-------|------------------| | API/Routes | routes/, api/, handlers/, controllers/ | | Service/Business Logic | services/, lib/, core/, domain/ | | Database/Storage | db/, models/, repositories/, schema/ | | UI/Presentation | components/, views/, templates/, pages/ | | Utility | utils/, helpers/, common/ |

Checklist:

• [ ] Read flow: Database -> Service -> API -> UI
• [ ] Write flow: UI -> API -> Service -> Database
• [ ] Types/schemas correctly passed between layers?
• [ ] Errors properly propagated to caller?
• [ ] Loading/pending states handled at each layer?

Detailed Guide: .trellis/spec/guides/cross-layer-thinking-guide.md

---

Dimension B: Code Reuse (Required when modifying constants/config)

Trigger:

• Modifying UI constants (label, icon, color)
• Modifying any hardcoded value
• Seeing similar code in multiple places
• Creating a new utility/helper function
• Just finished batch modifications across files

Checklist:

• [ ] Search first: How many places define this value?

  # Search in source files (adjust extensions for your project)
  grep -r "value-to-change" src/
  

• [ ] If 2+ places define same value -> Should extract to shared constant
• [ ] After modification, all usage sites updated?
• [ ] If creating utility: Does similar utility already exist?

Detailed Guide: .trellis/spec/guides/code-reuse-thinking-guide.md

---

Dimension B2: New Utility Functions

Trigger: About to create a new utility/helper function

Checklist:

• [ ] Search for existing similar utilities first

  grep -r "functionNamePattern" src/
  

• [ ] If similar exists, can you extend it instead?
• [ ] If creating new, is it in the right location (shared vs domain-specific)?

---

Dimension B3: After Batch Modifications

Trigger: Just modified similar patterns in multiple files

Checklist:

• [ ] Did you check ALL files with similar patterns?

  grep -r "patternYouChanged" src/
  

• [ ] Any files missed that should also be updated?
• [ ] Should this pattern be abstracted to prevent future duplication?

---

Dimension C: Import/Dependency Paths (Required when creating new files)

Trigger: Creating new source files

Checklist:

• [ ] Using correct import paths (relative vs absolute)?
• [ ] No circular dependencies?
• [ ] Consistent with project's module organization?

---

Dimension D: Same-Layer Consistency

Trigger:

• Modifying display logic or formatting
• Same domain concept used in multiple places

Checklist:

• [ ] Search for other places using same concept

  grep -r "ConceptName" src/
  

• [ ] Are these usages consistent?
• [ ] Should they share configuration/constants?

---

Common Issues Quick Reference

| Issue | Root Cause | Prevention | |-------|------------|------------| | Changed one place, missed others | Didn't search impact scope | grep before changing | | Data lost at some layer | Didn't check data flow | Trace data source to destination | | Type/schema mismatch | Cross-layer types inconsistent | Use shared type definitions | | UI/output inconsistent | Same concept in multiple places | Extract shared constants | | Similar utility exists | Didn't search first | Search before creating | | Batch fix incomplete | Didn't verify all occurrences | grep after fixing |

---

Output

Report:

1. Which dimensions your changes involve
2. Check results for each dimension
3. Issues found and fix suggestions