Pull Request Size Best Practices

// Large feature: Add order discount system (would be ~1200 lines)

// PR 1: Add database schema and entity (150 lines)
@Entity
public class Discount {
    @Id
    private Long id;
    private String code;
    private BigDecimal percentage;
    private LocalDateTime expiresAt;
}

// PR 2: Add repository and basic service layer (200 lines)
@Service
public class DiscountService {
    private final DiscountRepository repository;

    public DiscountService(DiscountRepository repository) {
        this.repository = repository;
    }

    public Optional<Discount> findByCode(String code) {
        return repository.findByCode(code)
            .filter(d -> d.getExpiresAt().isAfter(LocalDateTime.now()));
    }
}

// PR 3: Integrate discount calculation into order flow (180 lines)
public BigDecimal calculateTotal(Order order, String discountCode) {
    var subtotal = order.getItems().stream()
        .map(Item::getPrice)
        .reduce(BigDecimal.ZERO, BigDecimal::add);

    return discountService.findByCode(discountCode)
        .map(d -> subtotal.multiply(BigDecimal.ONE.subtract(d.getPercentage())))
        .orElse(subtotal);
}

// PR 4: Add REST endpoint behind a feature flag (120 lines)