Code Review

Code Review

Review the code changes for compliance with project conventions defined in AGENTS.md files.

Instructions

1. Identify changed files - Determine what to review:

   • If on a feature branch: git diff main...HEAD to see all changes vs main
   • If reviewing staged changes: git diff --cached
   • If user specifies files in $ARGUMENTS: review those directly

   To list only changed file paths: git diff main...HEAD --name-only

2. Read and check each changed file against the relevant checklist below

3. Report violations with specific line numbers and fix suggestions

4. Praise compliant code briefly when patterns are followed correctly

Backend Checklist (Python files in backend/)

Pydantic v2 Syntax (CRITICAL)

Pydantic v1 syntax is DEPRECATED. Always use v2 patterns:

Correct example:

from pydantic import BaseModel, ConfigDict, Field, field_validator

class UserRead(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: UUID
    email: str | None = None
    tags: list[str] = Field(default_factory=list)

    @field_validator("email")
    @classmethod
    def validate_email(cls, v: str | None) -> str | None:
        if v and "@" not in v:
            raise ValueError("Invalid email")
        return v

Layer Separation (CRITICAL)

Repositories (app/repositories/)

• ONLY database operations (queries, inserts, updates, deletes)
• Input/output: SQLAlchemy models only, NEVER Pydantic schemas
• NO business logic, validation, or external API calls
• Methods should be simple, focused CRUD operations

Correct:

class UserRepository(CrudRepository[User, UserCreate, UserUpdate]):
    def get_by_email(self, db: DbSession, email: str) -> User | None:
        return db.query(self.model).filter(self.model.email == email).one_or_none()

    def get_active_users(self, db: DbSession) -> list[User]:
        return db.query(self.model).filter(self.model.is_active == True).all()

Services (app/services/)

• Contains ALL business logic
• NEVER performs database operations directly (use repositories)
• Coordinates between repositories, external APIs, and other services
• Handles validation beyond Pydantic schema validation and error handling

Correct:

class UserService(AppService[UserRepository, User, UserCreate, UserUpdate]):
    def create_with_welcome_email(self, db: DbSession, data: UserCreate) -> User:
        user = self.crud.create(db, data)  # Delegates to repository
        email_service.send_welcome(user.email)  # Business logic here
        return user

    def get_premium_users_with_discount(self, db: DbSession) -> list[UserWithDiscount]:
        users = self.crud.get_premium(db)  # Repository handles query
        return [self._apply_discount(u) for u in users]  # Logic in service

Modern Python Syntax

Use modern Python 3.10+ syntax:

Generics (Python 3.12+):

# Redundant in most cases that accept type aliases - using TypeVar
from typing import TypeVar, Generic

T = TypeVar("T")

class Repository(Generic[T]):
    def get(self, id: int) -> T: ...

# Modern - using type parameter syntax
class Repository[T]:
    def get(self, id: int) -> T: ...

# Function generics
def first[T](items: list[T]) -> T | None:
    return items[0] if items else None

Type hints are required - all functions must have type annotations:

# Correct
def process_user(db: DbSession, user_id: UUID, active: bool = True) -> User | None:

# Incorrect
def process_user(db, user_id, active=True):

Imports

• All imports MUST be at the top of the file (module level), never inside functions or methods
• Lazy imports inside functions are NOT allowed — they hurt readability and hide dependencies

Error Handling

• Use raise_404=True in service methods instead of manual checks
• Let exceptions propagate to global handlers
• Use log_and_capture_error for caught exceptions in background tasks

Review Output Format

For each violation found, report:

### [VIOLATION] {Category}

**File:** `path/to/file.py:{line_number}`
**Issue:** {Brief description}

**Current code:**
```python
{offending code}

Should be:

{corrected code}

At the end, provide a summary:
- Total violations found
- Breakdown by category (Pydantic v2, Layer Separation, Type Hints, etc.)
- Overall assessment (PASS / NEEDS FIXES)