Apply Stack Conventions

When writing or generating code for this project, follow these conventions. Stack: Ruby on Rails, PostgreSQL, Hotwire (Turbo + Stimulus), Tailwind CSS.

Style: If the project uses a linter, treat it as the source of truth for formatting. For cross-cutting design principles (DRY, YAGNI, structured logging, rules by directory), use apply-code-conventions.

HARD-GATE: Tests Gate Implementation

ALL new code MUST have its test written and validated BEFORE implementation.
  1. Write the spec: bundle exec rspec spec/[path]_spec.rb
  2. Verify it FAILS — output must show the feature does not exist yet
  3. Write the implementation code
  4. Verify it PASSES — run the same spec and confirm green
  5. Refactor if needed, keeping tests green
See write-tests for the full gate cycle.

Feature Development Workflow

For a typical feature, compose stack patterns in this order:

1. Model — add validations, associations, scopes; eager-load with includes for any association used in loops
2. Service object — extract non-trivial business logic from the controller (see create-service-object)
3. Controller — keep actions thin; delegate to services; respond with turbo_stream and html formats
4. View / Turbo wiring — wrap dynamic sections in <turbo-frame> tags; broadcast turbo_stream responses from the controller
5. Stimulus — add a controller only when client-side interactivity cannot be handled by Turbo alone
6. Tailwind — apply utility classes to the view; extract repeated patterns into partials or Stimulus targets

Each step should remain testable in isolation before wiring to the next layer.

Key Code Patterns

Hotwire: Turbo Frames

<%# Wrap a section to be replaced without a full page reload %>
<turbo-frame id="order-<%= @order.id %>">
  <%= render "orders/details", order: @order %>
</turbo-frame>

<%# Link that targets only this frame %>
<%= link_to "Edit", edit_order_path(@order), data: { turbo_frame: "order-#{@order.id}" } %>

Hotwire: Turbo Streams (broadcast from controller)

respond_to do |format|
  format.turbo_stream do
    render turbo_stream: turbo_stream.replace(
      "order_#{@order.id}",
      partial: "orders/order",
      locals: { order: @order }
    )
  end
  format.html { redirect_to @order }
end

Avoiding N+1 — Eager Loading

# BAD — triggers one query per order
@orders = Order.where(user: current_user)
@orders.each { |o| o.line_items.count }

# GOOD — single JOIN via includes
@orders = Order.includes(:line_items).where(user: current_user)

Service Object (complex business logic out of the controller)

# Controller stays thin — delegate to service
result = Orders::CreateOrder.call(user: current_user, params: order_params)
if result[:success]
  redirect_to result[:order], notice: "Order created"
else
  @order = Order.new(order_params)
  render :new, status: :unprocessable_entity
end

See create-service-object for the full .call pattern and response format.

Security

This project uses Devise for authentication and Pundit for authorization. Apply these on every feature that introduces access-controlled resources.

Pitfalls to Avoid

Integration