Spree Promotions

Before writing code

Fetch live docs:

1. Fetch https://spreecommerce.org/docs/developer/core-concepts/promotions for the canonical model.
2. Inspect the live Spree::PromotionRule / Spree::PromotionAction source — bundled rule/action classes change between minors.
3. Check the v5.1 announcement for the advanced rule-based engine introduced there.
4. For custom calculators, review live examples in the app/models/spree/calculator/ directory of the spree gem.
5. Check the latest release notes for any promotions changes (v5.0 added coupon batch CSV export).

Conceptual Architecture

The Four Building Blocks