How to Modify an Existing Feature Safely

IMPLEMENTED

Before altering any business logic, database models, or API endpoints:

1. Run Verification Pre-Flight

Always run the full test suite to establish a passing baseline:

cd backend && venv/bin/python manage.py test

Confirm 153/153 tests pass.

2. Invariant Check Before Editing

Ask yourself these questions:

• Does this change introduce cross-tenant data leakage?
• Does it bypass host-derived multi-tenancy?
• Does it delete or alter records from LedgerEntry directly?
• Does it execute synchronous external network I/O in an HTTP view thread?

3. Verify Frontend Production Build

If modifying frontend components or types:

cd frontend && npm run build

Verify Turbopack compilation passes with 0 TypeScript or linting errors.