2026-05-02: Fix AssetTypeGroup enum cast in Prisma repository

Status: Complete

Context

After merging all branches into main (see 2026-05-02 merge plan), running npm run docker:reset still failed — this time during the backend Docker build step (npx nest build):

src/infrastructure/repositories/prisma-asset-type.repository.ts:30:51 - error TS2322:
Type 'string' is not assignable to type 'AssetTypeGroup'.

The bug was introduced when the group field was added to AssetType (plan D1). The repository adapter was wired to pass data.group directly from the domain port type (string) to Prisma’s typed input ($Enums.AssetTypeGroup).

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Root Cause

Hexagonal architecture correctly keeps Prisma types OUT of the domain layer:

• AssetType entity: group: string ✅
• CreateAssetTypeData / UpdateAssetTypeData ports: group: string ✅

But the infrastructure adapter (PrismaAssetTypeRepository) did not perform the necessary cast at the boundary:

// Before (broken)
data: { code: data.code, label: data.label, group: data.group }
//                                          ^^^ string ≠ $Enums.AssetTypeGroup

// After (fixed)
data: { code: data.code, label: data.label, group: data.group as $Enums.AssetTypeGroup }

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Fix

File: backend/src/infrastructure/repositories/prisma-asset-type.repository.ts

1. Added $Enums to the @prisma/client import
2. Cast data.group as $Enums.AssetTypeGroup in create()
3. Cast data.group as $Enums.AssetTypeGroup in update()

The cast is safe because the domain validation layer (class-validator on DTOs + domain entity) ensures only valid enum string values reach the repository.

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Test Added (AGENTS.md Convention #5 — Bug-to-Test)

New file: backend/test/asset-type.e2e-spec.ts

Covers:

• POST /api/v1/asset-types with a group enum value → 201
• PUT /api/v1/asset-types/:id to update group → 200
• DELETE /api/v1/asset-types/:id → 200

Uses real NestJS app + in-memory SQLite. Would have caught the compile error at e2e time.

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AGENTS.md Enforcement Improvement

Created .github/instructions/agents-plan-checklist.instructions.md with applyTo: '**/*'.

The .github/instructions/ mechanism is the strongest enforcement tool for AI agents in this repo: these files are explicitly shown with a forced-read reminder before any code change. By adding the 8 AGENTS.md conventions as a mandatory checklist here, they cannot be missed.

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Trade-offs

• Cast vs. validation: using as cast is appropriate here because the infrastructure layer is the boundary where Prisma types belong. The domain stays clean.
• Instruction file vs. AGENTS.md: AGENTS.md remains the prose source of truth; the instruction file is a compact checklist derivative that triggers the enforcement mechanism.